(March 4, 2010 - Insidermedicine)

Longer wait times for radiotherapy following breast conserving therapy for breast cancer are associated with an increased risk of recurrence, according to research published online ahead of print in the British Medial Journal.

Here are some management guidelines for postmastectomy radiotherapy from the American College of Radiology:

•    Postmastectomy radiotherapy (PMR) is indicated in patients with T3N1 and T4N1&2 primary tumors as well as T1-2 disease with 4 or more positive nodes.

•    Some controversy remains regarding the benefit of PMR for patients with T1-2N1 disease (i.e., one to three positive lymph nodes)
 
•    All postmastectomy patients with primary tumors larger than 5 cm with involved axillary nodes, or locally advanced (T4, N2) tumors should be irradiated.

Researchers out of Dana-Farber Cancer Institute in Boston retrospectively analyzed the relationship between wait times for radiotherapy and recurrence rates among 18,050 U.S. women with stage 0-II breast cancer aged 65 or older. All patients received breast conserving surgery and radiotherapy but not chemotherapy.

The median time from surgery to the start of radiotherapy was 34 days, with 29.9% of women starting after six weeks. Just over 4% of the participants experienced a local recurrence. After adjusting for clinical and sociodemographic factors, waiting six weeks or more for radiotherapy was associated with a 19% increased risk of recurrence. The relationship between time to radiotherapy and recurrence was continuous. Multivariate analysis revealed that waits of more than six weeks were significantly associated with positive nodes, comorbidity, history of low income, Hispanic ethnicity, non-white race, later year of diagnosis, and residence outside the southern U.S.

Today's research highlights the need to deliver radiotherapy as soon as possible after breast conserving surgery among women with breast cancer.