Selective sentinel lymph node biopsy in male breast cancer

Surgery for Men with Breast Cancer: Do the Same Data Still Apply?

BACKGROUND

Men represent a small proportion of breast cancer diagnoses, and they are often excluded from clinical trials. Current treatments are largely extrapolated from evidence in women. We compare practice patterns between men and women with breast cancer following the publication of several landmark clinical trials in surgery.

PATIENTS AND METHODS

Patients with invasive breast cancer (2004-2015) from the National Cancer Data Base were identified; subcohorts were created based on eligibility for NSABP-B06, CALGB 9343, and ACOSOG Z0011. Practice patterns were stratified by gender and compared. Cox proportional hazards regression analyses were utilized to estimate the association between OS and gender.

RESULTS

Of the 1,664,746 patients identified, 99% were women and 1% were men. Among NSABP-B06 eligible men, mastectomy rates did not change (consistently ~ 80%), and their adjusted OS was minimally worse compared with women (HR 1.19, 95% CI 1.11-1.28). Following publication of CALGB 9343, omission of radiation after lumpectomy was less likely in men and lagged behind that of women, despite similar OS (male HR 0.92, 95% CI 0.59-1.44). Application of ACOSOG Z0011 findings resulted in deescalation of axillary surgery for men and women with comparable OS (male HR 0.69, 95% CI 0.33-1.45).

CONCLUSIONS

Uptake of clinical trial results for men with breast cancer often mirrors that for women, despite exclusion from these studies. Furthermore, when study findings were applied to eligible patients, men and women demonstrated similar survival. Observational studies can help inform the potential application of study findings to this unique population and improve patient enrollment in clinical trials.

Current state of surgical management for male breast cancer

Management guidelines for male breast cancer have long been extrapolated from those for female breast cancer, which are based on large, randomised-controlled trials. While there are no randomised-controlled trials for male breast cancer management mainly due to the rarity of the disease, the only type of evidence available comes from retrospective studies, subject to selection biases and small sample sizes. Male breast cancer, while similar to female breast cancer in many respects, has some important differences that can affect management choices. Most cancers are oestrogen and progesterone receptor positive, and usually more advanced at presentation than female breast cancer. This is likely due to less breast parenchyma in male patients and delay to diagnosis. The classical management option for male patients with breast cancer is mastectomy, due to small tumour-to-breast ratio and often central position of the tumour. Breast conserving surgery is still useful in selected cases and has similar outcomes when compared to mastectomies in these patients. For patients with clinically negative lymph nodes, sentinel lymph node biopsy offers the same prognosis as axillary lymph node dissection, but with less associated morbidity. Endocrine therapy is of particular use, due to high levels of receptor positivity. Adjuvant endocrine therapy seems to significantly improve overall survival of male patients with breast cancer and while no prospective evidence exists for neoadjuvant hormonal therapy, there is hope that this is a useful management option as well. Radiotherapy is also useful in an adjuvant setting, particularly when combined with endocrine therapy. Better identification of patients, less delay from presentation to diagnosis and more collaborative efforts are key in improving the management, prognosis and outcomes of patients with male breast cancer.