Impact on Survival of Primary Tumor Resection in Women with Metastatic Breast Cancer at Initial Diagnosis. The Alamo Project.

Abstract Background: Recent medical and scientific reports suggest that surgery of the primary tumor (PT) could be taken into account, although far from the current standard of care, in metastatic breast cancer (MBC) patients. The mechanistic basis for these findings stem from crosstalk between the PT and metastatic foci, immunosuppressive effects, and/or the avoidance of metastatic re-seeding from the primary source. We have focused on implementing surgical excision of the PT in certain settings and tumor types in order to ascertain whether this aggressive treatment modality can be justified in a classic palliative setting. Methods: The ALAMO Project (A) is a retrospective analysis of patients (pts) diagnosed with BC between 1990 and 1997 across 43 GEICAM hospitals. Patterns of BC presentation (tumor and host characteristics), treatment and survival were recorded in 2 cohorts, AI (1990-93, 4532 pts, closed by 2000) and AII (1994-97, 10849 pts, closed by 2003). Only MBC pts at first diagnosis were included, excluding those with secondary tumors, without a minimum of 2 months follow-up at the same institution, and without complete information regarding their PT surgery. Descriptive, Kaplan-Meier and Cox regression analyses were carried out. Results: 6.12% of the ALAMO database pts were initially diagnosed with MBC (605 fulfilled the present analysis criteria), with a medium age of 61.6 years (yrs). 54.2% had single-organ metastasis, anatomically distributed in skin/soft tissue (18.8%), bone (35.9%), lung (9.8%), and other viscera (35.5%). 26.3% of pts had surgery of the PT (83.7% of them radical procedures, 73.3% of them axillary dissected and 5.6% received radiotherapy). Chemotherapy (30.7%), endocrine therapy (23.1%) or both (41.7%) were the systemic approaches, and 4.5% received supportive care. Women in the surgery (S) group (159 pts) were younger, with skin/soft tissue or bone metastasis and oligometastatic disease. 5-yr overall survival (OS) was 18.84%, 2.94 yrs median OS in the S-group versus 1.83 yrs in the nS-group (p<0.001). A stratified analysis by organ showed relevant effects of surgery for pts with skin/soft tissue metastasis, 4.52 yrs versus 1.77 yrs median OS in the S and nS arms respectively. The multi-adjusted HR for surgery in this subgroup was 0.30 (p<0.001), which was not significantly modified considering a propensity score (PS) factor (HR 0.29, p<0.001). Surgery (p<0.001), systemic treatment (p<0.001), and the interaction between surgery and metastatic location (p<0.004) were included in the multivariate predictive model of survival for the whole series. Discussion: Local surgery of the PT is associated with an increase in OS for pts with skin/soft tissue metastasis and is maintained in multi-adjusted models. These analyses suggest that loco-regional control of the PT should be considered for the treatment of advanced disease in selected patients, but must be further investigated in randomized controlled trials in MBC at first diagnosis. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3104.