Higher risk of subsequent mastectomy, acute complication, long-term toxicity with APBI-brachy
WEDNESDAY, Dec. 7 (HealthDay News) -- Accelerated partial breast brachytherapy (APBI-brachy), in older women with invasive breast cancer treated with conservative surgery, is less effective and more toxic than whole breast irradiation (WBI), according to a study presented at the annual San Antonio Breast Cancer Symposium, held from Dec. 6 to 10.
Grace L. Smith, M.D., Ph.D., from the University of Texas M.D. Anderson Cancer Center in Houston, and colleagues compared the effectiveness and toxicity outcomes of APBI-brachy versus WBI after conservative surgery in 130,535 older women (>66 years), diagnosed with invasive breast cancer between 2000 and 2007. The two groups were compared for cumulative incidence and multivariate adjusted risk of subsequent mastectomy, as well as risks of acute complications (hospitalization or infection within 120 days of radiation) and their adjusted odds. The two groups were also compared for cumulative incidences of long-term toxicities.
The investigators found that patients treated with APBI-brachy showed significantly higher cumulative incidence of subsequent mastectomy at five-years than WBI (4 versus 2.2 percent). On multivariate analysis, there was a two-fold increased risk of subsequent mastectomy in the APBI-brachy versus WBI group (hazard ratio, 2.14). Compared to WBI, APBI-brachy correlated with more acute complications, including a significantly higher risk of hospitalization and infection (adjusted odds ratio, 1.71 and 1.85, respectively). The five-year cumulative incidence of rib fracture, fat necrosis, and breast pain were significantly higher with APBI-brachy than WBI, but pneumonitis had significantly lower incidence with APBI-brachy.
"APBI-brachy was associated with inferior effectiveness as well as increased acute and late toxicities compared with WBI," the authors write.