Radiation Delays Associated with Worse Outcomes in Localized Breast Cancer
Women who delay radiation treatment after surgery for early-stage breast cancer have worse outcomes than women who undergo radiation sooner, according to two recent studies, one published in the Journal of Clinical Oncology and the other in Cancer.
Early-stage breast cancer refers to cancer that has not spread outside the breast or axillary (under the arm) lymph nodes to distant sites in the body. Treatment for early-stage breast cancer involves either mastectomy (removal of the entire breast) or lumpectomy (removal of the cancer and some surrounding tissue) followed by radiation therapy. The radiation therapy is used to kill any cancer cells that may remain in the body following surgery and significantly reduces the risk of a cancer recurrence.
Radiation therapy is associated with side effects as well as significant time commitments for patients and caregivers. Radiation is delivered on a daily schedule, and patients must often travel great distances to the radiation treatment facility. Although radiation therapy following lumpectomy has been shown to reduce the risk of recurrence, research indicates that many women either forego or delay their radiation treatment, possibly because of the difficulties associated with receiving the treatment.
The delivery of prescribed cancer treatment at a specific time and schedule is critical for producing the best outcomes from treatment. Research is ongoing to determine the effects of delaying radiation therapy after surgery.
Researchers from Cornell used data from the Surveillance, Epidemiology, and End Results (SEER) database to evaluate the outcomes of 7,791 women with ductal carcinoma in situ (DCIS) or early-stage breast cancer who were treated between 1991 and 1999. They defined delay of radiation therapy (RT) as therapy that was delivered more than eight weeks after surgery without chemotherapy or more than four weeks after chemotherapy. Their analysis revealed that 16% of women delayed RT and 3% did not complete treatment. (Several varying factors appeared to be associated with this lack of compliance, including poverty, distance from a radiation facility, and race.) Furthermore, the results of the analysis indicated that women with Stage I breast cancer who delayed RT were more likely to experience a recurrence of their cancer and those with incomplete RT had a lower survival rate. Delays of more than 12 weeks (or more than eight weeks after chemotherapy) had a strongly negative impact on disease-free survival.
In another study researchers from Canada evaluated the outcomes of 6,428 women with early-stage breast cancer who were treated with lumpectomy and RT. These researchers studied the differences in outcomes among women who received RT at different intervals (within four weeks of surgery; four to eight weeks after surgery; eight to12 weeks; 12-16 weeks; 16-20 weeks; or more than 20 weeks). The median follow-up time was 7.5 years, and the majority of women received radiation between four and 12 weeks after surgery. The results indicated that the group of women receiving RT 20 or more weeks after surgery had a twofold worse outcome compared with women who were treated between four and eight weeks. These researchers concluded that although it is reasonable to allow the breast to heal after surgery, it is important to begin RT within 20 weeks of surgery.
Research is ongoing in this arena, but both of these studies add to the growing body of evidence that time is of the essence in order to produce the best possible outcomes for women with early-stage breast cancer.
 Olivotto IA, Lesperance ML, Truong PT, et al. Intervals longer than 20 weeks from breast-conserving surgery to radiation therapy are associated with inferior outcome for women with early-stage breast cancer who are not receiving chemotherapy. Journal of Clinical Oncology. 2008;early release on November 17.
 Gold HT, Do HT, Dick AW. Correlates and effect of suboptimal radiotherapy in women with ductal carcinoma in situ or early invasive breast cancer. Cancer. 2008;113:3108-3115.
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