According to an article recently published in the International Journal of Radiation Oncology, Biology and Physics, radiation therapy delayed for up to 16 weeks following surgery may not affect outcomes in patients with node-negative breast cancer.
Breast cancer is diagnosed in approximately 250,000 individuals annually in the U.S. alone. Node-negative breast cancer refers to the earliest stage of breast cancer. At this stage, cancer has not spread to the lymph nodes under the arm. Standard treatment for node-negative breast cancer includes the surgical removal of the cancer and surrounding tissue followed by radiation therapy.
The addition of radiation therapy to surgery has demonstrated a reduction in the risk of a cancer recurrence for women with early breast cancer. There are, however, certain drawbacks to radiation therapy. Traveling to and from radiation treatments, for instance, is sometimes inconvenient for women and their families. In addition, some women may experience complications following surgery (although this is rare), and radiation therapy may have to be delayed to allow healing.
Researchers from Canada recently conducted a study to determine whether delayed radiation therapy affects outcomes of women with node-negative breast cancer. This study included 568 patients who underwent surgery and radiation therapy without systemic (full-body) therapy between 1985 and 1992.
The following time intervals of delayed radiation therapy were analyzed: 0-8 weeks following surgery; greater than 8 to 12 weeks following surgery; greater than 12 to 16 weeks following surgery; and greater than 16 weeks following surgery. The median follow-up was over 11 years.
- There were no significant differences in terms of local cancer recurrences (recurrences near the site of the original cancer) between the groups of patients treated with radiation at different time intervals following surgery.
- There were no significant differences in terms of cancer-free survival between the groups of patients.
- At 5 years, local recurrences occurred in 4.6% of patients.
- At 10 years, local recurrences occurred in 11.3% of patients.
- At 5 years, cancer-free survival was nearly 80% among all patients.
- At 10 years, cancer-free survival was 67% among all patients.
The researchers concluded that radiation therapy delivered up to 16 weeks following surgery appears to provide similar outcomes to radiation therapy delivered immediately following surgery among patients with node-negative breast cancer. However, all patients with breast cancer should speak with their physician regarding their individual risks and benefits of timing of radiation therapy for their disease.
Reference: Vujovic O, Yu E, Cherian A, et al. Eleven-Year Follow-Up Results in the Delay of Breast Irradiation After Conservative Breast Surgery in Node-Negative Breast Cancer Patients. International Journal of Radiation Oncology, Biology and Physics. 2006;64: 760-764.