SAN FRANCISCOTime to failure, time to distant metastasis, and time to death in patients with early-stage breast cancer are not influenced by the order in which chemotherapy and radiotherapy are initiated, according to updated results of a study presented at the 43rd Annual Meeting of the American Society for Therapeutic Radiology and Oncology (ASTRO plenary 4). These latest long-term results are in contrast to earlier findings from the study.
"The initial results of the study were published in 1996 with 58 months of follow-up," said Jennifer Bellon, MD, an instructor at Brigham and Women’s Hospital, Boston. At that time, she said, patients randomized to the radiotherapy-first arm had a lower 5-year crude rate of local recurrence, whereas the patients randomized to the chemotherapy-first arm had a lower rate of distant and/or regional metastasis."Adjuvant chemotherapy preceding radiation has become common practice in women with early-stage breast cancer who undergo breast-conserving surgery," she said.
The new 10-year findings show no significant difference in freedom from any recurrence, freedom from distant metastasis, or overall survival between the two arms, Dr. Bellon said, based on a median follow-up of 135 months. She added that the power to detect differences, which is based on number of failures, is still low, and that additional results from this and other trials are necessary to determine the optimal therapy sequence.
The Boston-based study followed 244 women with stage I/II carcinoma of the breast treated with breast-conserving surgery. They were randomized to receive, after surgery, 12 weeks of chemotherapy either before radiotherapy (CT-first arm) or following radiotherapy (RT-first arm).
The two arms were matched for tumor and patient characteristics, including age, T stage, margins, and nodal status (for details, see N Engl J Med 334:1356-1361, 1996).
Chemotherapy consisted of a six-drug regimen repeated every 3 weeks for four cycles. Tamoxifen(Drug information on tamoxifen) (Nolvadex) was given following completion of all chemotherapy and radiotherapy to 11 patients in the CT-first arm and 7 patients in the RT-first arm.