Radiation After Lumpectomy Better for Most Older, Early-Stage Breast Cancer Patients

The potential benefit of radiation in this patient population has been the focus of much research over the past 10 years, according to Benjamin Smith, MD, assistant professor in the department of radiation therapy at the University of Texas MD Anderson Cancer Center (Houston, TX, USA), and the study’s corresponding author.

In 2004, a major study revealed that women who received tamoxifen alone, compared to tamoxifen and six weeks of radiation, had a slightly higher incidence of breast cancer recurrence. Nevertheless, there was no difference in mastectomy rates or survival between the two cohorts, according to Dr. Smith. Based on these findings, the US National Comprehensive Cancer Network (NCCN; Fort Washington, PA, USA), adjusted its treatment guidelines, and radiation therapy following lumpectomy was no longer recommended. Dr. Smith then followed up this guideline-changing research with a population-based study, confirming the earlier findings with respect to breast cancer recurrence.

“The motivation for this new research was to do a similarly designed study with longer term follow up,” stated Dr. Smith. “We wanted to do a 10-year update, focusing specifically on the mastectomy question. The fundamental reason it was determined that women didn’t need radiation was because the additional therapy did not change mastectomy rates.”

For the population-based study, Dr. Smith and his colleagues derived a cohort of US Medicare patients from the National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) registry who would have been eligible for the 2004 study. The researchers identified 7,403 patients ages 70-79 treated with a lumpectomy for early-stage estrogen-positive breast cancer. All were diagnosed between 1992 and 2002, with follow-up through 2007. Of the 7,403 women, 88% received radiation after their lumpectomy.

Within 10 years of their treatment, 6.3% of the women who did not receive radiation therapy had a mastectomy, likely because of a breast cancer recurrence, according to Dr. Smith, compared to 3.2% who had the further treatment. In patients with high-grade tumors, irrespective of other factors such as age and/or tumor characteristics, radiation appeared to be very beneficial. The researchers also discovered a subset of women for whom radiation did not benefit, and therefore could be omitted from care regimen: those 75-79 years of age who had their lymph nodes assessed and did not have high-grade tumors.

“I think the national guidelines, while well intended and important, may gloss over the certain nuances needed for making critical decisions with patients,” concluded Dr. Smith. “Our study may shed additional light on some of those nuances and provides data that physicians can use when talking to their patients about whether to go forward with radiation. Personally, having this data point, together with the previous findings, gives me the confidence to not routinely recommend radiation in women age 75 and over with non-high grade tumors.”

Related Links:
University of Texas MD Anderson Cancer Center
US National Comprehensive Cancer Network