Temporal and regional variation in the use of breast-conserving surgery and radiotherapy for older women with early-stage breast cancer from 1983 to 1995

Background. Authorities recommend radiation therapy after breast- conserving surgery for breast cancer. Numerous studies have reported that older women diagnosed with breast cancer are less likely to receive radiation after breast-conserving surgery. It is unclear how care of older women with breast cancer has changed over time. Methods. Women with local or regional stage breast cancer diagnosed between 1983-1995 were identified from the Surveillance, Epidemiology, and End Results (SEER) Cancer Registries. The treatment information in SEER includes type of surgical procedures and receipt of radiation therapy. Results. There were small increases in the percentage of women receiving breast-conserving surgery during the 1980s followed by substantial increases in the 1990s. Age was a major factor in determining receipt of radiation therapy after breast-conserving surgery. A large increase in use of radiotherapy after surgery was observed in women aged ≥75, from below 30% in 1983 to over 50% in 1995. Women aged ≥75 diagnosed in 1992-1995 were 1.76 and 2.34 times more likely to receive radiation for local and regional stage respectively, as compared to those in 1983-1987. There was no increase in use of radiation for women aged <65. Conclusions. There has been a substantial increase in use of breast- conserving surgery and in receipt of radiation therapy after breast- conserving surgery in older women. However, there was a net increase in the percentage of all women with breast cancer who received this surgery without radiotherapy, due to the large increase in the overall percentage of women receiving this surgery.