Women with stage I to stage III breast cancer who underwent breast-conserving surgery plus radiotherapy demonstrated significantly improved all-cause and breast cancer-specific survival compared with those who underwent mastectomy, according to a retrospective analysis of outcomes of patients treated in a public health care setting in Canada.
Previous randomized trials suggested patients with early-stage breast cancer who undergo mastectomy demonstrated outcomes comparable to those who underwent mastectomy plus breast conserving surgery. However, recent studies conducted in the United States and Canada have started to reveal a survival benefit for breast conserving surgery plus radiotherapy, according to study background.
Marcy Winget, MD, clinical associate professor in the school of medicine at Stanford University, and colleagues used the Alberta Cancer Registry to identify 14,633 patients with stage I to stage III breast cancer diagnosed between 2002 and 2010 who underwent mastectomy or breast conservation surgery.
Patients who underwent breast conservation surgery followed by radiotherapy demonstrated a higher unadjusted rate of 5-year all-cause survival (94%) than those who underwent mastectomy (83%) and breast conserving therapy alone (74%).
“This difference was seen even after taking into account and controlling for the effects of demographic, clinical and other treatment factors, including age,” Winget told HemOnc Today. “The consistency of our findings with some other similar large population-based studies published in the past year are in contrast to clinical trials conducted 15 or more years ago. There have been many advancements in surgical techniques and other treatment modes for breast cancer since the original trials, which may explain the discrepant results.”
Results showed receipt of mastectomy was associated with worse outcomes among women with stage II and stage III disease, including a higher risk for all-cause mortality (stage II, HR = 1.36; 95% CI, 1.13-1.48; stage III, HR = 1.74; 95% CI, 1.24-2.45) and breast cancer-specific mortality (stage II, HR = 1.39; 95% CI, 1.09-1.75; stage III, HR = 1.79; 95% CI, 1.21-2.65).
The findings suggest greater effort is needed to educate and encourage patients to receive breast conserving surgery plus radiotherapy instead of mastectomy “when medically feasible and appropriate,” the researchers concluded.
“Observational studies such as those recently conducted, however, do not prove causality, so it is unclear whether there is a true survival benefit for stage II and III breast cancer patients to receive breast conservation surgery plus radiation therapy over mastectomy,” Winget said. “Alternatively, it may be that women who are more likely to survive are selected preferentially to receive breast conservation surgery plus radiotherapy rather than mastectomy. Further studies are needed to better understand the relationship between breast cancer treatment options and survival, including specific investigations of various subgroups such as the elderly.” – by Anthony SanFilippo
For more information:
Marcy Winget, MD, can be reached at Stanford University, 450 Via Palou, Stanford, CA, 94305; email: email@example.com
Disclosure: The researchers report no relevant financial disclosures.