A National Survey of Breast Surgeons and Radiation Oncologists on Contemporary Axillary Management in Mastectomy Patients

Radiotherapy Trends and Variations in Invasive Non-metastatic Breast Cancer Treatment in the Netherlands: A Nationwide Overview From 2008 to 2019

AIMS

This nationwide study provides an overview of trends and variations in radiotherapy use as part of multimodal treatment of invasive non-metastatic breast cancer in the Netherlands in 2008-2019.

MATERIALS AND METHODS

Women with invasive non-metastatic breast cancer were selected from the population-based Netherlands Cancer Registry. Treatments trends were presented over time. Factors associated with (1) boost irradiation in breast-conserving therapy and (2) regional radiotherapy instead of axillary lymph node dissection (ALND) in N+ disease were identified using multilevel logistic regression analyses.

RESULTS

Radiotherapy use increased from 61% (2008) to 70% (2016), caused by breast-conserving therapy instead of mastectomy, increased post-mastectomy radiotherapy, and increased regional radiotherapy (32% in 2011 to 61% in 2019) instead of ALND in N+ disease. Omission of radiotherapy after breast-conserving surgery (BCS) in 2016-2019 (4-9%, respectively), mainly in elderly, decreased overall radiotherapy use to 67%. Radiotherapy treatment was further de-escalated by decreased boost irradiation in breast-conserving therapy (66% in 2011 to 37% in 2019) and partial (1% in 2011 to 6% in 2019) instead of whole breast irradiation following BCS. Boost irradiation was associated with high-risk features: younger age (OR>75 vs <50:0.04, 95%CI:0.03-0.05), higher grade (OR grade III vs I:11.46, 95%CI:9.90-13.26) and residual disease (OR focal residual vs R0-resection:28.08, 95%CI:23.07-34.17). Variation across the country was found for both boost irradiation use (OR South vs North:0.58, 95%CI:0.49-0.68), and regional radiotherapy instead of ALND (OR Southwest vs North:0.55, 95%CI:0.37-0.80).

CONCLUSION

Overall radiotherapy use increased in 2008-2016, while a decreasing trend was observed after 2016, caused by post-BCS radiotherapy omission. Boost irradiation in breast-conserving therapy became omitted in low-risk patients, and regional radiotherapy use increased as an alternative for ALND in N+ disease.

Does Neoadjuvant Chemotherapy in Clinical T1-T2 N0 Triple-Negative Breast Cancer Increase the Extent of Axillary Surgery?

BACKGROUND

Current management strategies for early-stage triple-negative breast cancer (TNBC) include upfront surgery to determine pathologic stage to guide chemotherapy recommendations, or neoadjuvant chemotherapy (NAC) to de-escalate surgery, elucidate tumor response, and determine the role of adjuvant chemotherapy. However, patients who receive NAC with residual pathological nodal (pN) involvement require axillary lymph node dissection (ALND) as they are Z11/AMAROS ineligible. We aimed to evaluate the impact of NAC compared with upfront surgery on pN status and ALND rates in cT1-2N0 TNBC.

METHODS

The National Cancer Database (NCDB) was queried for women with operable cT1-2N0 TNBC from 2014 to 2019. Demographic, clinicopathologic, and treatment data were collected. Multivariable linear regression analysis was performed to assess the odds of pN+ disease and undergoing ALND.

RESULTS

Overall, 55,624 women were included: 26.9% (n = 14,942) underwent NAC and 73.1% (n = 40,682) underwent upfront surgery. The NAC cohort was younger (mean age 52.9 vs. 61.3 years; p < 0.001) with more cT2 tumors (71.6% vs. 31.0%; p < 0.001), and had lower ALND rates (4.3% vs. 5.5%; p < 0.001). The upfront surgery cohort was more likely to have one to three pathologically positive nodes (12.1% vs. 6.5%; odds ratio [OR] 2.37, 95% confidence interval (CI) 2.17-2.58; p < 0.001) but there was no difference in the likelihood of ALND (OR 1.1, 95% CI 0.99-1.24; p = 0.08).

CONCLUSION

Patients who underwent upfront surgery were more likely to be pN+; however, ALND rates were similar between the two cohorts. Thus, the use of NAC does not result in a higher odds of ALND and the decision for NAC should be individualized and based on modern guidelines and systemic therapy benefits.

Intraoperative Pathology Assessment May Lead to Overtreatment of the Axilla in Clinically Node-Negative Breast Cancer Patients Undergoing Upfront Mastectomy

BACKGROUND

Randomized trials have established the safety of observation or axillary radiation (AxRT) as an alternative to axillary lymph node dissection (ALND) in patients with limited nodal disease who undergo upfront surgery. Variability remains in axillary management strategies in cN0 patients undergoing mastectomy found to have one to two positive sentinel lymph nodes (SLNs). We examined the impact of intraoperative pathology assessment in axillary management in a national cohort of AMAROS-eligible mastectomy patients.

METHODS

The National Cancer Database was used to identify AMAROS-eligible cT1-2N0 breast cancer patients undergoing upfront mastectomy and SLN biopsy (SLNB) and found to have one to two positive SLNs, from 2018 to 2019. We constructed a variable defining intraoperative pathology as 'not performed/not acted on' if ALND was either not performed or performed at a later date than SLNB, or 'performed/acted on' if SLNB and ALND were completed on the same day. Adjusted multivariable analysis examined predictors of treatment with both ALND and AxRT.

RESULTS

Overall, 8222 patients with cT1-2N0 disease underwent upfront mastectomy and had one to two positive SLNs. Intraoperative pathology was performed/acted on in 3057 (37.2%) patients. These patients were significantly more likely to have both ALND and AxRT than those without intraoperative pathology (41.0% vs. 4.9%; p < 0.001). On multivariate analysis, the strongest predictor of receiving both ALND and AxRT was use of intraoperative pathology (odds ratio 8.99, 95% confidence interval 7.70-10.5; p < 0.001).

CONCLUSIONS

We advocate that consideration should be made for omission of routine intraoperative pathology in mastectomy patients likely to be recommended postmastectomy radiation to minimize axillary overtreatment with both ALND and AxRT in appropriate patients.

Contemporary approaches to the axilla in breast cancer

Over the past decade, axillary management in breast cancer has fundamentally shifted. The former notion that any degree of axillary nodal involvement warrants axillary lymph node dissection (ALND) has been challenged. Following publication of the ACOSOG Z0011 trial, national trends demonstrated significant reductions in ALND performance. Axillary radiotherapy in lieu of ALND is a consideration for select patients with a positive sentinel lymph node, while ongoing studies are investigating the role of adjuvant regional radiotherapy in women with positive nodes prior to neoadjuvant chemotherapy. Efforts toward de-escalation of axillary surgery continue to evolve, as do the indications for sentinel node biopsy omission in select subsets of patients. This review highlights the recent advances and neoteric approaches to local therapy of the axilla in breast cancer.

Surgical Management of the Axilla for Breast Cancer

This review discusses the contemporary surgical management of the axilla in patients with breast cancer. Surgical paradigms are highlighted by clinical nodal status at presentation and treatment approach, including upfront surgery and neoadjuvant systemic therapy settings. This review focuses on the increasing opportunities for de-escalating the extent of axillary surgery in the era of sentinel lymph node biopsy, while also reviewing the remaining indications for axillary clearance with axillary lymph node dissection.

Escalating de-escalation in breast cancer treatment

Efforts have continually been made to de-escalate treatment for breast cancer, with the goal of balancing oncologic outcomes with complications and patient quality of life. In the early 2000s, two landmark studies firmly established that conservative treatment approaches for breast cancer can be safe and effective. More recently, neoadjuvant chemotherapy has gained momentum as a potential standard of care for breast cancer. An important question has thus arisen: Can neoadjuvant approaches themselves be de-escalated to further minimize adverse treatment effects while maintaining oncological outcomes? In this editorial, we look at the available evidence and assess current trends in treatment de-escalation for women with breast cancer.

Postmastectomy Radiation Therapy in Patients With Minimally Involved Lymph Nodes: A Review of the Current Data and Future Directions

Radiation therapy for patients with pN1mi or pN1 disease breast cancer undergoing mastectomy has been debated for a long time. Even in low metastatic burden in sentinel node biopsy, occult non-sentinel axillary nodal involvement can exist. Radiotherapy can sterilize axillary metastatic burden and seems to contribute a very low local recurrence rate in mastectomy patients with minimally involved lymph nodes. However, it should be considered that systemic therapy is evolving and the local recurrence difference between radiotherapy and no radiotherapy is relatively small. Regarding postmastectomy radiotherapy in patients pN1mi or pN1 cancer, published prospective clinical trial results should be considered; however, there are no such relevant results of clinical trials yet. Consideration of postmastectomy radiation therapy in pN1mi or pN1 patients should be based on identifying the high-risk group in terms of recurrence, stage, or tumor biology. When radiotherapy is determined, radiation oncologists should attempt individualized treatment approaches, such as irradiation field, and consider specific settings, such as neoadjuvant therapy. In this review, the role of radiotherapy in mastectomy patients with minimally involved lymph nodes and the relevant considerations are discussed.

Breast cancer-related lymphedema rates after modern axillary treatments: How accurate are our estimates?

BACKGROUND

Clinical trials have demonstrated methods to minimize the risk of breast cancer-related lymphedema while preserving regional control. We sought to determine the percent lifetime-risk of breast cancer-related lymphedema that surgeons and radiation oncologists discuss with patients before axillary interventions.

METHODS

A nationwide survey of surgeons and radiation oncologists was performed from July to August 2020. Participants were asked to identify what number they discuss with patients when estimating the percent lifetime-risk of breast cancer-related lymphedema after different axillary interventions.

RESULTS

Six hundred and eighty surgeons and 324 radiation oncologists responded (14% response rate). While the estimated rate after sentinel lymph node biopsy was clinically similar between surgeons and radiation oncologists, statistically surgeons quoted a higher percent lifetime-risk (5.7% vs 5.0%, P = .03). Surgeons estimated significantly higher rates of breast cancer-related lymphedema compared with radiation oncologists (P < .001) for axillary lymph node dissection (21.8% vs 17.5%), sentinel lymph node biopsy with regional nodal irradiation (14.1% vs 11.2%), and axillary lymph node dissection with regional nodal irradiation (34.8% vs 26.2%).

CONCLUSION

There is variability in the estimated rates of breast cancer-related lymphedema providers discuss with patients. These findings highlight the need for physician education on the current evidence of percent lifetime-risk of breast cancer-related lymphedema to provide patients with accurate estimates before axillary interventions.