Radiation therapy extends life in older women with early breast cancer, according to 2 different studies presented at the ASTRO 54th Annual Meeting.
The first study showed that the addition of radiation to lumpectomy improved overall survival (OS) as well as breast cancer–specific survival (CSS) in women aged 70 or older.1
“Age alone should not impact whether or not radiation treatment is presented as a viable treatment option for elderly women with early breast cancer,” stated Randi Cohen, MD, from the University of Maryland School of Medicine, Baltimore.
The study population included 29,949 women identified in a SEER [Surveillance, Epidemiology and End Results] Medicare database who were diagnosed with stage I, estrogen receptor–positive (ER+) breast cancer. All women underwent lumpectomy with or without adjuvant radiation and survived at least 1 year after initial diagnosis. Seventy-six percent (22,781) received adjuvant radiation therapy.
Median survival was 13.1 years for women treated with surgery plus radiation and 11.1 years for those treated with surgery alone. Five-year CSS was 98.3% for the adjuvant radiation group versus 97.6% for the surgery-alone group, a statistically significant difference (P <.0001). Ten-year CSS was 95.4% versus 93.3%, respectively (P <.0001); 15-year CSS was 91.4% versus 89.5%, respectively.
At all time points, the use of adjuvant radiation improved OS. At 5 years, OS was 88.6% for those who received radiation versus 73.1% for the surgery-alone arm (P <.0001); at 10 years, OS was 65% versus 41.7%, respectively (P <.0001); at 15 years, OS was 39.6% versus 20%, respectively.
A related study based on 27,559 patients from a SEER Medicare database found that older women with early-stage, low-risk breast cancer treated with radiation after breast-conserving surgery (BCS) had superior CSS and OS rates, compared with women who did not undergo radiation after BCS.2 The study showed a 6% decline in the use of radiation after 2004, coinciding with revised National Comprehensive Cancer Network guidelines allowing omission of radiation therapy as a reasonable option for women over age 70 with small ER+ tumors treated with adjuvant tamoxifen.
The study was presented by Mariam P. Korah, MD, a radiation oncologist at the University of Southern California Keck School of Medicine in Los Angeles.
Breast cancer–specific survival favored radiotherapy. At 5 years, CSS was 97% for radiotherapy versus 95%, an absolute difference of 2%; by 8 years, the absolute difference was doubled to 4%, favoring radiation: 95% and 91%, respectively.
OS also favored the addition of radiotherapy to surgery. Five-year OS was 87% versus 69%, respectively, with an absolute difference of 18% favoring radiation, and 8-year OS was 73% versus 49%, respectively, for an absolute difference of 24% favoring radiation.
- Cohen RJ, Li L, Citron W, et al. Improved survival with adjuvant radiation in elderly women with early-stage breast cancer. Presented at: American Society for Radiation Oncology 54th Annual Meeting; October 29, 2012; Boston, MA. Abstract 82.
- Korah MP, Sener SF, Tripathy D. Implications of omitting radiation after breast conserving surgery in elderly women with low risk invasive breast cancer. Presented at: American Society for Radiation Oncology 54th Annual Meeting; October 29, 2012; Boston, MA. Abstract 84.