Endocrine adjuvant therapy in male breast cancer (MBC): tamoxifen (TAM), aromatase inhibitors (AI) or both?.

Abstract

Abstract Abstract #4133 Background:
 MBC represents less than 1% of male cancers and occurs 10 years later than in women. Hormone receptors (HR) are very often positive, thus TAM is considered the standard endocrine adjuvant treatment (ET); AI has not been evaluated yet in this setting. To our knowledge, this is the first report focused on this option.
 Material and methods:
 From 1990 to 2005, 489 non metastatic patients were collected in 15 cancer centers. Median age was 66 years (34% over 70) and median follow-up was 60 months.
 204 (42%) patients had at least one “chronic disease” (mainly cardiovascular: 20%, metabolic: 10%, respiratory: 6% and neurological: 3%).
 Results:
 There were 39% T1, 41% T2, 9% T3T4, 11% Tx, and 27% N1N2. Lumpectomy and mastectomy were performed in 10% and 90% of the cases. Axillary dissection , sentinel node biopsy or both were performed in 90%, 2% and 5% of the cases, respectively.
 95% of the tumors were ductal carcinomas; 47% were pT1, 20% pT2 and 33% pT3T4. Axillary nodal involvement (ANI) was present in 52.8% of the cases. ER were evaluable in 419 (86%) tumors, including 92% positive. PgR were evaluable in 399 (82%) tumors, including 89% positive. The distribution of HR was: ER+PgR+: 86%; ER+PgR-: 6%; ER-PgR+: 3.3%; ER-PgR-: 4.7%. 417 patients (85%) underwent locoregional radiotherapy. 106 patients (21%) had no adjuvant treatment at all, 30 (6%) had chemotherapy alone, 218 (45.3%) had endocrine therapy alone (ET) and 134 (27.6%) had CT+ET. Adjuvant treatment significantly changes according to pT, pN, SBR grading, presence of vascular emboli and age. Among 344 patients who received ET, 301 (87%) underwent TAM, 34 (10%) AI and 9 (3%) TAM followed by AI. The use of AI was not influenced by pT or pN, but was slightly more frequent in older patients as well as in case on associated comorbidities. For the entire cohort, local recurrence (LR), nodal recurrences (NR) and metastases occurred in 2%, 5% and 22% of the cases; 2% and 10% developed contralateral BC and second cancer. The 5 and 10-year overall survival (OS) rates were 81% and 59%; disease-specific survivals (DSS) were 89% and 72%. Death causes were BC 56%, second cancer 8%, complications 3%, intercurrent disease 15% and unknown 18%. Metastatic risk factors were T stage (T1: 19%, T2: 26%, T3T4: 40%; p= 0.013), pN status (pN0: 12, pN1-3: 26, pN>3: 44%; p<0.0001) and presence of locoregional recurrence (62% versus 18% p<0.0001).Among patients under ET, event rates were very similar in TAM and AI (+/- TAM) groups : LR + NR : 7% vs 5% ; metastases : 21% vs 28% and deaths : 22% vs 24%.
 Conclusion:
 Due to high median age and comorbidity frequency, ET remains the best option in MBC patients. Tamoxifen and AI seem to have a very similar efficiency and tolerance. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4133.