For most elderly women with early stage breast cancer, radiation after lumpectomy helps prevent need for subsequent mastectomy
Findings contrary to current treatment guidelines
- Date : 16 Aug 2012
- Topic : Breast cancer
For the majority of older, early-stage breast cancer patients, radiation therapy following breast conserving surgery may help prevent the need for a later mastectomy, according to research from The University of Texas MD Anderson Cancer Centre. The findings, published in the journal Cancer, are contrary to current treatment guidelines, which recommend that older women with early stage, estrogen-positive disease should be treated with lumpectomy followed by oestrogen blocker therapy alone.
The potential benefit of radiation in this patient population has been the focus of much research over the past decade, according to Dr Benjamin Smith, assistant professor in the Department of Radiation Therapy at MD Anderson and the study's corresponding author. In 2004, a major study found that women who received tamoxifen alone, compared to tamoxifen and six weeks of radiation, had a slightly higher incidence of breast cancer recurrence. Yet, there was no difference in mastectomy rates or survival among the two cohorts. Based on these findings, the NCCN adjusted its treatment guidelines, and radiation therapy following lumpectomy was no longer recommended. Smith then followed up this guideline-changing research with a population-based study, confirming the earlier findings with respect to breast cancer recurrence.
New findings indicate that current evaluation of the risks and benefits of radiation for early stage breast cancer in older women may be inaccurate
The motivation for this new research was to do a similarly designed study with longer term follow-up. The researchers wanted to do a 10-year update, focusing specifically on the mastectomy question. The fundamental reason was determined that women didn't need radiation because the additional therapy did not change mastectomy rates.
For the population-based study, Smith and colleagues derived a cohort of Medicare patients from the USA 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 oestrogen-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, compared to 3.2% who had the additional treatment. The researchers were also able to identify which women were more and less likely to benefit from radiation. Specifically, radiation did not seem to benefit women ages 75 to 79 years with non-high grade tumours, suggesting that this group can probably skip radiation. Patients with high grade tumours, regardless of age, seemed to derive the most benefit from radiation.
These data are important because they suggest that radiation is of some benefit to certain women where guidelines do not recommend the radiation. This study may shed additional light on some of nuances needed for making clinical decisions and provides data that physicians can use when talking to their patients about whether to go forward with radiation. Together with the previous findings, it gives more confidence to not routinely recommend radiation in women age 75 and over with non-high grade tumours.
In addition to other MD Anderson authors, the study included also researchers of The University of Chicago. The study was funded, in part, by research grants from Varian Medical Systems, USA Department of Health and Human Services and the National Cancer Institute. Drs Giordano and Smith are supported by a grant from the Cancer Prevention and Research Institute of Texas. None of the authors declare any conflicts.
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