A new study recently presented at the annual American Association for Cancer Research (AACR) Meeting in Washington, D.C. has reported some differences between patterns of progression of triple negative (ER-/PR-, not HER2 overexpressing) breast cancer and other types. The study included 585 patients diagnosed with Stage 0 to III breast cancer and treated between January 1999 and December 2006. The median age of the women was 53 years (range: 27 to 84 years) and they were staged as follows: 55 Stage 0; 272 Stage I; 206 Stage II; and 49 Stage III. Fifty nine (13.5%) of the 440 patients who were assessable were found to have triple negative breast cancer. All of the patients were treated with surgery, either lumpectomy (552) or mastectomy (33). After surgery, the women were treated with radiation. Chemotherapy was given to 170 patients, hormonal therapy was given to 168, and 161 patients received both.
After a median follow-up period of 61 months (range: 3 to 137 months), 18 (3.1%) local recurrences and 41 (7.0%) distant relapses had occurred among the 585 patients. Thirty-one patients had died, of whom 23 died from breast cancer. In the study group overall, the first distant metastasis was most often detected in bone (25%), liver (17%), lung (15%), and brain (8%). In 34% of cases, metastatic disease was found in multiple organs when first detected. The median time to distant metastasis was 34 months, and 88% of the relapses took place before 60 months. However among women with triple negative breast cancer, the rate of distant relapse was 13.5% and local relapse was 5.1%. Median time to distant metastasis was 25 months (range: 8 to 48 months). Locoregional relapses were found mostly in the breast or chest wall (16 or 89% of locoregional relapses), with fewer lymph node relapses (2, 11%). The median time to locoregional recurrence was 32 months (range: 8 to 78 months), with 78% of relapses occurring before 60 months. However, no differences were found in the patterns of relapse between the groups. The authors comment that distant recurrences mostly involved bone, liver, and lung, with about one third of patients being found to have multiple organ metastasis when relapse was detected. In the triple negative subgroup there was an increased risk of distant relapse with a shorter time to relapse. No differences in time and site patterns were found relative to locoregional recurrences.