Men with breast cancer died more than 2 years sooner than did women with the condition, in the largest-ever study of male breast cancer, investigators reported.
Male breast cancer patients presented with more advanced disease and had lower 5-year survival rates as well as shorter median overall survival than did women, Dr. Jon M. Greif said at the annual meeting of the American Society of Breast Surgeons.
They were less likely to have radiation therapy or partial mastectomy, but chemotherapy rates were not significantly different, said Dr. Greif, a breast surgeon who practices in Oakland, Calif.
The data come from an analysis of 13,457 men – representing 0.9% of all breast cancers – and 1,439,866 women with breast cancer in the National Cancer Data Base spanning the years 1998 through 2007. The explanation for the differences in overall survival is most likely multifactorial, according to Dr. Greif.
"Certainly, one reason is that with well accepted screening for female breast cancer, and heightened awareness amongst women, female breast cancer is detected earlier. Evidence from our study is that male breast cancer is larger and more likely to have spread to lymph nodes and beyond when first discovered," he said in an interview.
"However, male breast cancer was less likely to be low grade, and this would be a biological difference. And, finally, men were older, and more likely to die of other causes."
Men at particularly high risk should have careful clinical examinations annually, and consider annual screening mammography, advised Dr. Greif. Among those at high risk, he included men with known gene mutations that increase their risk (BRCA and Klinefelter’s syndrome, for example), men who have been treated or otherwise exposed to high levels of radiation to the chest, men with previous breast cancer, and men with strong family histories of male or female breast cancer.
"Currently, breast cancer in men is found as a palpable retro- or periareolar mass, a nipple discharge or crusting, skin erosion, or palpable lymph nodes. Examination of the retroareolar and periareolar tissues for lumps and/or skin changes should be a part of every man’s annual physical exam, and men should check occasionally themselves," Dr. Greif said.
Five-year overall survival was 83% for women with breast cancer (median survival 129 months) and 74% for men (median 101 months), a highly statistically significant difference (P less than. 0001), he reported.
A comparison of overall survival by stages showed significantly better outcomes for women with early disease, but similar outcomes in more advanced disease. Females had significantly better 5-year survival rates (P less than .0001) for stage 0 (94% vs. 90%), stage I (90% vs. 87%) and stage II (82% vs. 74%) breast cancer. No significant differences were seen in 5-year survival for stage III (56.9% vs. 56.5%, P = .99) or stage IV (19% vs. 16%, P = .20).
The following findings also were reported:
– Men with breast cancer were more often African American (11.7% vs. 9.9%, odds ratio 1.19), less often Hispanic (3.6% vs. 4.5%, OR 0.74), and older (63 vs. 59 years old).
– Men had larger tumors (median 20.0 vs. 15.0 mm), were less likely to have grade 1 tumors (16.0% vs. 20.7%), were more likely to have lymph node metastasis (41.9% vs. 33.2%, OR 1.45), and were more likely to have distant metastasis (4% vs. 3%, OR 1.39).
– Men were less likely to have lobular carcinoma (10% vs. 18%, OR 0.51) and more likely to be estrogen receptor positive (88.3% vs. 78.2%, OR 2.10) and progesterone receptor positive (76.8% vs. 67.0%, OR 1.63).
– Men were less likely to have been treated with a partial mastectomy (33% vs. 62%, OR 0.31) and less likely to have received radiation (35.9% vs. 50.4%, OR 0.55).
All of these differences were highly statistically significant, with P values less than .0001. However, the differences may not have been of clinical significance, the investigators said, citing the large numbers of cases.
The proportions of men and women receiving chemotherapy were similar (40.1% vs. 39.8%, OR 1.01, P = .40) and only small differences were seen in hormonal therapy rates (41.2% vs. 42.4%, OR 0.95, P = .006).
Treatment of male breast cancer is similar to that of female breast cancer, according to Dr. Greif. Nearly all male breast cancers are hormone receptor positive, so treatment with antiestrogenic endocrine therapy should be a part of the adjuvant treatment of nearly all male breast cancer.
Chemotherapy should be considered for tumors with higher risk of systemic return, he said. For tumors with risk of locoregional return, including those that are large and/or have lymph node involvement, adjuvant radiation should be part of the treatment.