Can Women Safely Skip Additional Lymph Node Surgery After Sentinel Node-Positive Breast Cancer? The SENOMAC Trial Explained

Table of Contents

• Key Points
• Background: Why This Research Matters
• What Previous Studies Have Shown
• Study Methods: How the SENOMAC Trial Is Designed
• Who Can Participate in This Study
• Patients Receiving Chemotherapy Before Surgery
• How Patients Are Randomized
• Quality of Life Questionnaires
• Adjuvant Therapy (Treatments After Surgery)
• Data Management and Follow-Up
• Sample Size and Statistical Power
• Data Monitoring Committee
• Statistical Methods Used
• Clinical Implications for Patients
• Study Limitations
• Recommendations for Patients
• Frequently Asked Questions
• Source Information

Key Points

• Skipping completion ALND after a positive sentinel node can reduce arm problems like swelling, pain, and limited mobility.
• Two earlier trials found no significant survival advantage with completion ALND, but both enrolled too few patients to detect small differences.
• The SENOMAC trial includes patients with larger tumors (T3), mastectomy, and neoadjuvant chemotherapy, which prior trials largely excluded.
• If a sentinel node contains macrometastasis, about 50–65% of patients have no additional cancer found in further lymph nodes removed.
• SENOMAC is a non-inferiority trial aiming to prove that skipping ALND is not meaningfully worse than standard surgery, not that it is better.

Background: Why This Research Matters

Lymph node metastasis — the spread of cancer to lymph nodes — is one of the most important factors in determining a breast cancer patient's prognosis (likely outcome). Lymph node metastases are classified into three categories based on the size of the cancer deposits found:

• Isolated tumor cells: clusters of cancer cells measuring no more than 0.2 mm and/or containing fewer than 200 cells
• Micrometastasis: cancer deposits larger than 0.2 mm but no larger than 2 mm, and/or containing more than 200 cells
• Macrometastasis: cancer deposits larger than 2 mm

The sentinel node (SN) is the first lymph node that cancer would likely spread to from the breast. Sentinel node biopsy — a procedure that removes and examines only this first node — has proven to be a reliable method for determining whether breast cancer has begun to spread. Several follow-up studies have shown that it is safe to refrain from completion axillary lymph node dissection (ALND), a more extensive surgery that removes many lymph nodes from the armpit, in patients whose sentinel node is cancer-free.

The greatest advantage of the sentinel node biopsy approach is a significant decrease in the frequency and severity of arm problems, such as lymphedema (arm swelling), pain, and limited mobility, since fewer lymph nodes are removed from the axilla (the armpit area).

However, in patients whose sentinel node does contain cancer (SN-positive patients), the question of whether to proceed with completion ALND remains controversial. In about 50–65% of SN-positive patients, no additional cancer is actually found in the remaining lymph nodes removed during ALND — meaning that for over half of these women, the extra surgery finds nothing and only adds risk of arm complications.

What Previous Studies Have Shown

After the publication of the landmark ACOSOG Z0011 trial in 2011, avoiding completion ALND in sentinel node-positive cases became widely accepted, especially in the United States. This trial randomly assigned SN-positive patients to either undergo ALND or skip additional axillary surgery. After a median follow-up period of over 6 years, no difference in the rate of axillary recurrence (cancer returning in the armpit area) was found. In fact, survival was even slightly better among patients who only underwent sentinel node biopsy: disease-free survival was 83.9%, compared with 82.2% for patients who underwent ALND. However, this difference was not statistically significant, meaning it could have been due to chance.

The ACOSOG Z0011 study has received some criticism. Notably, it only included patients with tumors up to 5 cm in size who underwent breast-conserving surgery (lumpectomy) and received whole-breast postoperative radiotherapy. This leaves important unanswered questions for other patient groups.

Another study, the IBCSG 23-01 trial, published in 2013, randomly assigned SN-positive patients to either undergo completion ALND or not. This study included only patients with SN micrometastases, but also showed slightly better disease-free survival in the group who had only sentinel node biopsy: 87.8%, compared with 84.4% for those who underwent ALND. Once again, this difference was not statistically significant.

Neither the ACOSOG Z0011 study nor the IBCSG 23-01 study succeeded in enrolling the planned number of patients, which means neither had sufficient statistical power to detect small survival differences reliably.

However, some research suggests that ALND may still have a therapeutic benefit in certain situations:

• A report by Park et al. found that the rate of axillary recurrence among SN-positive patients who did not undergo ALND was a striking 2.0% after just 30 months, despite otherwise favorable prognostic factors — compared with 0.4% among those who underwent completion ALND.
• The Dutch MIRROR study found that the rate of axillary recurrence was more than twice as high among patients with micrometastases who did not undergo ALND compared with sentinel node-negative patients.
• A large European study called AMAROS randomized over 1,400 SN-positive patients — including 861 with SN macrometastases — to either undergo completion ALND or receive axillary radiotherapy. It showed no difference in disease-free or overall survival between the two approaches, leading several countries to now approve axillary radiotherapy as an alternative to surgery.

Despite this growing evidence, none of the described trials included a sufficient number of patients treated by mastectomy (complete breast removal) to draw reliable conclusions about the need for ALND in that group. It is also unclear whether the tumor size limit of 5 cm used in earlier trials is appropriate, or whether larger (though not locally advanced) tumors could be managed the same way. Finally, with the increasing international use of neoadjuvant systemic therapy (NAST — chemotherapy given before surgery), the question of how to surgically treat the armpit after NAST in patients who had a positive sentinel node biopsy before treatment remains unanswered. The SENOMAC trial was designed to address these highly important questions through an international collaborative effort.

Study Methods: How the SENOMAC Trial Is Designed

The SENOMAC trial is a prospective (forward-looking), randomized, multicenter, non-inferiority study. In plain language, a "non-inferiority" study is designed to prove that a less invasive treatment is not meaningfully worse than the standard treatment — rather than trying to prove it is better. This is an important distinction because the goal is to confirm that skipping ALND is safe, not necessarily superior.

Patients are randomly assigned 1:1 (like flipping a coin) to one of two groups:

• Arm A: Undergo completion ALND (removal of additional lymph nodes from levels I and II of the armpit)
• Arm B: Receive no further axillary surgery

The trial is conducted according to Good Clinical Practice (GCP) guidelines, which are international ethical and scientific quality standards for designing, conducting, and recording clinical trials.

The main aim is to evaluate whether it is safe to refrain from completion ALND in individuals with breast cancer and sentinel node macrometastasis (cancer deposits larger than 2 mm).

Primary endpoint: Breast cancer-specific survival at 5 years — meaning the percentage of patients who have not died from breast cancer five years after entering the study.

Secondary endpoints: These include locoregional recurrence (cancer returning in the breast or nearby lymph nodes), disease-free survival, overall survival, arm morbidity (arm problems such as swelling, pain, or limited movement), health economic outcomes, and health-related quality of life.

Before surgery, all patients undergo what is called "triple diagnostics" — the standard approach including clinical assessment (physical examination), imaging evaluation (such as mammogram or ultrasound), and cytological or histopathological confirmation of the diagnosis (examination of cells or tissue under a microscope). Ultrasound of the axillary region is required, and any suspicious lymph nodes must be biopsied. Interestingly, patients with up to two non-palpable (not able to be felt) preoperatively diagnosed axillary metastases may still undergo sentinel node biopsy and be included in the trial.

All types of breast surgery are eligible — both breast-conserving surgery (lumpectomy) and mastectomy, with or without breast reconstruction. The use of frozen section analysis (rapid microscopic examination of tissue during surgery) may be performed or omitted depending on local hospital practice.

Who Can Participate in This Study

The trial has specific inclusion (who can join) and exclusion (who cannot join) criteria.

Inclusion criteria — patients must have all of the following:

1. Primary invasive breast cancer classified as T1-T3 (tumors up to 5 cm or slightly larger but not locally advanced, according to the TNM classification system)
2. A preoperative ultrasound of the axilla performed
3. Macrometastasis (cancer deposit larger than 2 mm) in no more than two lymph nodes at sentinel node biopsy
4. Written informed consent
5. Age 18 years or older

Exclusion criteria — patients with any of the following cannot join:

• Palpable (able to be felt) regional lymph node metastasis prior to surgery
• Regional or distant metastases outside of the ipsilateral axilla (the armpit on the same side as the breast cancer)
• Pregnancy
• Bilateral invasive breast cancer, if one side meets any of the exclusion criteria
• Medical contraindication (a reason they cannot safely receive) for radiotherapy or systemic treatment
• Inability to absorb or understand the meaning of the study information — for example, through disability, inadequate language skills, or dementia
• Prior history of invasive breast cancer

Patients Receiving Chemotherapy Before Surgery

The SENOMAC trial has a unique feature: it includes patients planned for neoadjuvant systemic therapy (NAST), meaning chemotherapy or other systemic treatment given before the main surgery. This is an important group because their numbers are rising internationally, and there is currently little evidence guiding how to manage their armpit lymph nodes.

Patients without palpable lymph node metastases may undergo sentinel node biopsy prior to starting their neoadjuvant treatment, then be randomized and included in the trial. Randomization is recommended to be performed before the start of neoadjuvant therapy, but must at the very latest take place before the first clinical or radiological response evaluation (the first check of whether the tumor is shrinking).

If the tumor progresses (grows) during NAST, or if palpable lymph node metastases appear, participation in the trial is discontinued. The reason for termination is recorded in the electronic Case Report Form (eCRF). The decision to discontinue participation must always be discussed at a multidisciplinary team conference, where multiple specialists review the patient's situation together.

How Patients Are Randomized

Randomization (the process of assigning patients to treatment groups by chance) is performed using a web-based tool. It can occur at one of two time points:

1. During surgery, after the frozen section results are received (allowing the ALND to be performed in the same session)
2. After surgery, once final histopathological results are available (requiring a second surgical session for Arm A patients)

Patients randomized to Arm A will undergo completion ALND of levels I and II — meaning removal of lymph nodes from two of the three levels of the armpit. Patients randomized to Arm B will have no further axillary surgery.

The randomization uses a permutated block technique with a 1:1 allocation ratio, and treatment arms are stratified per country (meaning the randomization is balanced within each participating country, not just overall). If the final histopathology results later show that a randomized patient does not actually meet all criteria — for example, an additional metastasis is identified during special sectioning of the sentinel node — that patient must be excluded from the study. Patients who meet all inclusion criteria and receive information about the trial but are not randomized are registered in screening logs at each site, which helps track the generalizability of the findings.

Quality of Life Questionnaires

An essential part of this study is measuring how treatment affects patients' daily lives. Questionnaires covering arm morbidity (arm problems), health-related quality of life, and health economics are provided at baseline (before treatment) and again after 1, 3, and 5 years.

The study uses several well-validated instruments (questionnaires that have been scientifically tested for accuracy and reliability):

• Lymph-ICF: The Lymphedema Functioning, Disability and Health Questionnaire, which specifically measures the impact of lymphedema (arm swelling) on daily functioning
• EQ-5D-5L: A standardized measure of health-related quality of life that generates utility scores for health economic analyses
• EORTC QLQ-30: A widely used cancer-specific quality of life questionnaire developed by the European Organisation for Research and Treatment of Cancer
• EORTC BR-23: A breast cancer-specific module that complements the QLQ-30

Both traditional paper and online versions of all instruments are available. Each patient's answers are coded with an individual study code (to protect privacy) and collected centrally at the Study Center in Stockholm, Sweden.

Adjuvant Therapy (Treatments After Surgery)

Adjuvant systemic therapy (treatments like chemotherapy, hormone therapy, or targeted drugs given after surgery) should be given in accordance with the national clinical guidelines of each participating country.

After breast-conserving surgery, radiation to the remaining breast tissue is mandatory. A "boost" dose to the tumor bed (the area where the tumor was removed) should be applied according to each country's national guidelines. Post-mastectomy radiotherapy (PMRT — radiation given after complete breast removal) and radiotherapy to regional lymph node basins are also based on each country's national guidelines.

A critical rule in this trial is that radiotherapy must not be extended or changed based on which arm the patient is randomized to. In other words, sentinel node biopsy only should be regarded as a substitute for axillary clearance — meaning the radiation plan is not adjusted to compensate for the surgical approach.

In Sweden, radiotherapy to regional lymph node basins follows the Swedish National Guidelines. The regional lymph node target (clinical target volume, or CTV) is composed of:

• Axilla level 2 (the middle group of lymph nodes)
• Axilla level 3 (the highest group, beneath the collarbone)
• Interpectoral lymph nodes (nodes between the chest muscles)
• Supraclavicular fossa (the area above the collarbone, also called axilla level 4)

Notably, level 1 (the lowest group of axillary lymph nodes) is omitted from the regional lymph node CTV in Swedish practice. Detailed volume descriptions follow the ESTRO consensus guideline on target volume delineation for elective radiation therapy of early stage breast cancer, version 1.1.

The exact regional lymph node target is reported in the eCRF prospectively throughout the trial. Irradiation of internal mammary nodes (lymph nodes inside the chest, near the breastbone) is handled according to each country's national guidelines, and this treatment must be recorded in the eCRF.

Radiation dosing follows local practice. Standard fractionation is 2 Gy per fraction × 25 treatments over 33–35 days to the breast and regional lymph nodes. A slightly lower total dose to the nodes (approximately 46 Gy) is accepted. Alternatively, hypofractionated radiotherapy (larger doses per session, fewer total sessions) can be used — specifically 2.67 Gy per fraction × 15–16 treatments over 19–22 days. Dose and fractionation schedules are reported prospectively.

Data Management and Follow-Up

All data are registered using an electronic Case Report Form (eCRF). Monitoring (the process of verifying that the trial is conducted correctly) is performed according to Good Clinical Practice guidelines. Information collected includes age, completed surgery, tumor and lymph node characteristics, neoadjuvant and adjuvant therapy details, and status at annual follow-up visits.

Data are managed by the Clinical Trial Unit at Karolinska University Hospital in Stockholm, Sweden.

Patients are followed with annual clinical examination and mammography for 5 years, with additional controls after 10 and 15 years. Each follow-up visit must take place within ±2 months of the randomization date, and data must be completed in the eCRF within 1 month of the follow-up visit.

Additional diagnostic measures — such as axillary ultrasound, biopsies, or other investigations — are carried out as clinically indicated. If axillary recurrence (cancer returning in the armpit) is suspected, a computed tomography (CT) scan of the thoracic region is required to determine the level of recurrence in the axilla and to rule out further metastatic spread.

Sample Size and Statistical Power

The goal of the study is to establish that the intervention (no further axillary surgery) is statistically non-inferior to the standard of care (completion ALND) for the primary endpoint of breast cancer-specific survival (BCSS) at 5 years.

Clinical non-inferiority is defined in this study as a 5-year BCSS not worsened by more than 2.5% when refraining from ALND. To demonstrate this — meaning a 5-year BCSS of 89.5% in the intervention group compared to 92% in the standard of care group, using a one-sided alpha (significance level) of 10% and with a statistical power of 80% — a total of 225 breast cancer deaths need to be observed during the study.

This corresponds to showing that the upper one-sided 90% confidence interval for the hazard ratio (HR, the ratio of risk of death between the two groups) falls below 1.33. In plain terms, researchers want to be 90% confident that skipping ALND does not increase the risk of breast cancer death by more than 33% at most, and ideally not at all.

Power calculations are based on Swedish data, which may differ from survival outcomes in other countries. Therefore, stratification according to the country of primary treatment is performed — meaning the randomization and analysis account for each patient's country.

The study is anticipated to recruit up to 700 patients per year during a 5-year period, giving a total sample size of 3,500 patients. With allowance for an extra year of follow-up, the necessary number of events (225 breast cancer deaths) is expected to be reached. The total study time will be approximately 7 years.

Data Monitoring Committee

An independent data monitoring committee (a group of experts not involved in the trial who review safety and progress) will review the data and carry out one closed interim analysis. This happens either 3 years after the first study patient was randomized, or when 2,000 patients have been included in the study — whichever comes first.

The purpose of this interim analysis is to:

• Assess recruitment to the study
• Evaluate the rate of overall breast-cancer-related events
• Ensure that patients in the intervention group do not appear to fare significantly worse than patients in the standard of care group

The committee may recommend terminating the study if a significant benefit in favor of standard of care (completion ALND) is shown for breast cancer deaths — specifically, if the hazard ratio for intervention versus standard of care significantly exceeds 1 (p = 0.001). This means the result would need to be extremely strong to stop the trial early. The committee may also recommend termination if recruitment is so low that the necessary number of events is unlikely to be reached. If the committee determines that it is safe to proceed with the study, the results of the interim analysis will remain unknown to everyone except committee members — this prevents bias during the rest of the trial.

Statistical Methods Used

The researchers are using rigorous statistical methods to analyze the results. For the primary endpoint, breast cancer-specific survival, time is calculated from the date of randomization to the date of breast cancer death (BCD). A breast cancer death is defined as a death with information of a preceding or concurrent regional or distant recurrence. Isolated ipsilateral in-breast recurrences (cancer returning only in the same breast) do not count toward breast cancer death, since the goal is to measure deaths truly caused by breast cancer's spread.

Disease-free survival time is calculated from the date of randomization to the date of locoregional recurrence (cancer returning in the breast or armpit area), distant recurrence (cancer spreading to other organs), second malignancy (a new, different cancer), or death — whichever comes first. For event-free patients (those who experience none of these events), time is calculated from the date of randomization to the date of the last visit.

Event-specific cumulative incidence rates — taking competing risks into account (meaning the risk of dying from other causes while being observed for breast cancer death) — are estimated using non-parametric methods. Differences in time to failure are tested using the log-rank test, a standard statistical test for comparing survival between two groups. The effect of the intervention on time to failure is estimated using proportional hazards regression, a method that calculates hazard ratios while adjusting for other factors.

Both unadjusted analyses and analyses adjusting for potential confounding factors are performed. Longitudinal health-related quality of life data are analyzed using generalized linear models. Tests for interactions between treatment and time — indicating a differential effect of treatment over time — are also performed. Both intent-to-treat analyses (analyzing everyone according to the group they were assigned, regardless of what actually happened) and treatment-received analyses (analyzing patients according to the treatment they actually received) are performed for the primary outcome. All analyses will use StataCorp 2015 statistical software.

Clinical Implications for Patients

This study matters for patients because it addresses real-world questions that doctors face every day. Despite the general decline in ALND use after the 2011 publication of the ACOSOG Z0011 results, there is still considerable variation in surgical management of the armpit across European centers. Even after the recent publication of long-term results from the same study — showing essentially no difference in recurrence rates between patients undergoing or omitting completion ALND — the base of evidence remains small.

A review by Schmidt-Hansen and colleagues identified only three prospective randomized trials comparing sentinel node biopsy with or without completion ALND in patients with sentinel node metastases, reporting on a total of only 2,020 patients. Of those three trials:

• Two exclusively included cases of sentinel node micrometastasis (AATRM 048/13/2000 and IBCSG-23-01)
• The third (ACOSOG Z0011) included only 430 patients with sentinel node macrometastases, while 301 patients had only sentinel node micrometastases, and the size of sentinel node metastasis was not reported for the 125 patients remaining in the intent-to-treat sample (total N = 856)

This means the evidence on the significance of completion ALND in patients with sentinel node macrometastasis is limited to a surprisingly small sample — mostly patients with T1-T2 tumors treated by breast-conserving surgery. Despite this, the use of ALND in sentinel node-positive disease appears to be decreasing even in patients treated by mastectomy, and in some places ALND is being replaced by regional radiotherapy based on the AMAROS trial results. This clearly leaves a need for further prospective trials, especially including patients treated by mastectomy — which is exactly what SENOMAC provides.

Study Limitations

As with any clinical trial, the SENOMAC trial has limitations that should be acknowledged. First, it is designed as a non-inferiority study, meaning it can show that skipping ALND is "not worse" by more than a small margin, but it cannot prove that skipping ALND is better than doing it. The non-inferiority margin of 2.5% in 5-year breast cancer-specific survival is a clinical judgment, and some might argue for a more strict or lenient margin.

Second, the power calculations are based on Swedish data, which may differ from survival outcomes in other countries. Although the researchers account for this by stratifying according to country, it remains a potential limitation. The trial also requires a total of 225 breast cancer deaths for adequate power — which depends on event rates matching expectations.

Third, the trial cannot answer what should be done for patients with more than two sentinel node macrometastases, those with palpable lymph node metastases, or those whose tumors progress during neoadjuvant therapy — these patients are excluded or discontinued from the study.

Fourth, the study results will take years to mature: the total study time is approximately 7 years, and the primary endpoint is 5-year survival, meaning final results for the primary analysis will not be available until well into the next decade. The 10- and 15-year follow-ups will take even longer to report.

Finally, while the study includes patients undergoing neoadjuvant therapy, the researchers note that sentinel node biopsy performed prior to NAST may necessitate a second axillary intervention (ALND) in the event of sentinel node macrometastases in clinically node-negative (cN0) patients. Some clinicians argue that a repeat sentinel node biopsy after NAST has a high false negative rate, though it is considered acceptable if at least three sentinel nodes can be identified — but this debate continues.

Recommendations for Patients

If you are a breast cancer patient facing decisions about lymph node surgery, there are several important takeaways from this study protocol:

1. Ask about your specific situation. Whether you are having breast-conserving surgery or a mastectomy, whether your tumor is small or large, and whether you will receive chemotherapy before surgery all affect whether current evidence supports skipping ALND. Older trials did not include many mastectomy patients or those with larger tumors, so the SENOMAC trial is designed to answer questions that have not been well studied before.
2. Understand the difference between a sentinel node biopsy and a completion ALND. A sentinel node biopsy removes only 1–3 nodes; a completion ALND removes many more lymph nodes from levels I and II of the armpit. The main benefit of skipping the bigger surgery is fewer arm problems like swelling (lymphedema), pain, and limited mobility — which can significantly affect daily life.
3. Know that the evidence is still evolving. The two key earlier trials (ACOSOG Z0011 and IBCSG 23-01) suggested no statistically significant survival advantage with ALND, but both had too few patients to detect small differences. The 2.0% axillary recurrence rate at 30 months in patients who skipped ALND in the Park et al. study is a reminder that the decision is not risk-free.
4. If you are considering neoadjuvant chemotherapy, ask when your sentinel node biopsy will be done. Some countries perform it before chemotherapy, others after. The SENOMAC trial will help answer whether ALND is necessary for patients who had sentinel node macrometastases before NAST, provided the tumor does not progress during treatment — but this evidence is not yet available.
5. Participate in clinical trials if you are eligible. The SENOMAC trial is enrolling patients across multiple European countries, including Sweden, Denmark, Germany, Greece, and Italy. Trial participation gives you access to careful monitoring, validated quality-of-life questionnaires, and the opportunity to contribute to better evidence for future patients.

The SENOMAC trial was registered at ClinicalTrials.gov with the identifier NCT 02240472, with retrospective registration on September 14, 2015, after trial initiation on January 31, 2015. The study is supported by grants from the Swedish Research Council, the Swedish Cancer Foundation, the Swedish Society of Medicine, the Swedish Breast Cancer Association (BRO), and the Swedish Society for Medical Research. None of the funding bodies had any part in the design of the study, data collection, or analysis.

Frequently Asked Questions

What is the difference between a sentinel node biopsy and a completion axillary lymph node dissection (ALND)?

A sentinel node biopsy removes only 1–3 lymph nodes, the first nodes cancer would likely spread to. A completion ALND removes many more lymph nodes from levels I and II of the armpit. Skipping the larger surgery reduces arm problems like swelling, pain, and limited mobility, which can affect daily life.

Am I eligible to participate in the SENOMAC trial?

You may be eligible if you are 18 or older, have primary invasive breast cancer classified as T1-T3, have a preoperative axillary ultrasound, and have macrometastasis (cancer deposits larger than 2 mm) in no more than two sentinel lymph nodes. You cannot join if you have palpable lymph node metastases or distant spread.

What happens if I am randomized to skip additional lymph node surgery?

You would receive no further axillary surgery beyond your sentinel node biopsy. Your doctors will follow national guidelines for radiotherapy and systemic therapy. The trial will monitor your survival, cancer recurrence, arm symptoms, and quality of life for up to 15 years with annual exams and mammograms.

Is it safe to skip completion ALND after a positive sentinel node biopsy?

Earlier trials, ACOSOG Z0011 and IBCSG 23-01, found no statistically significant survival advantage with ALND, but both lacked enough patients to detect small differences. The SENOMAC trial is designed to prove that skipping ALND is not meaningfully worse than standard surgery for certain patients, including those with larger tumors or mastectomy.

What are the risks of skipping completion ALND?

The main risk is cancer returning in the armpit area. One study of patients who skipped ALND reported a 2.0% axillary recurrence rate after 30 months, compared with 0.4% with ALND. However, the SENOMAC trial aims to confirm that for many patients, the risk is not meaningfully higher, and avoiding ALND reduces arm complications.

I am receiving chemotherapy before surgery. Can I still join the SENOMAC trial?

Yes, the trial includes patients planned for neoadjuvant systemic therapy. You may undergo sentinel node biopsy before starting treatment, then be randomized. Randomization should occur before starting neoadjuvant therapy or at the latest before the first response evaluation. If your tumor progresses during treatment, participation is discontinued.

What does the 5-year breast cancer-specific survival endpoint mean?

It is the percentage of patients who have not died from breast cancer five years after entering the study. The SENOMAC trial aims to show that skipping completion ALND does not worsen this survival by more than 2.5% compared with standard surgery. The primary analysis will be available after about 7 years of total study time.

When should I seek a second opinion about whether to have more lymph node surgery after a sentinel node biopsy shows cancer?

If you have sentinel node-positive breast cancer and your doctor recommends completion axillary lymph node dissection, a second opinion can clarify whether that extra surgery is necessary. Research shows that in 50–65% of such patients, no additional cancer is found in the remaining lymph nodes, while the surgery increases risks of arm swelling, pain, and limited mobility. However, previous key trials included few mastectomy or larger-tumor patients, and evidence is still evolving. A second opinion can weigh your specific tumor size, surgery type, chemotherapy timing, and personal risk. Diagnostic Detectives Network provides independent expert second opinions.

Source Information

Original article title: S T U D Y P R O T O C O L Open Access Survival and axillary recurrence following sentinel node-positive breast cancer

Authors: Jana de Boniface, Jan Frisell, Yvette Andersson, Leif Bergkvist, Johan Ahlgren, Lisa Rydén, Roger Olofsson Bagge, Malin Sund, Hemming Johansson, Dan Lundstedt, on behalf of the SENOMAC Trialists' Group

Journal: BMC Cancer (2017) 17:379

DOI: 10.1186/s12885-017-3361-y

Trial registration: NCT 02240472

This patient-friendly article is based on peer-reviewed research. The original article is an open-access study protocol published under the Creative Commons Attribution 4.0 International License, which permits unrestricted use, distribution, and reproduction.