Carlos Arteaga, MD
Carlos Arteaga, MD, of Vanderbilt-Ingram Cancer Center, Nashville, Tennessee, said, “Breast-conserving therapy is the right thing to do. This study will not change current practice guidelines. Mastectomy is generally reserved for larger tumors and those with multifocal disease. The study just emphasizes the value of breast-conserving therapy.” Dr. Arteaga moderated a press conference at the 2015 San Antonio Breast Cancer Conference where these data were discussed.
Words of Caution
The fact that these findings fly in the face of randomized controlled trials makes me wonder about the unmeasured confounding factors. Questions remain about selection bias, and I hope the [final] manuscript will address those.— Anees B. Chagpar, MD
Anees B. Chagpar, MD, Director at Yale-New Haven Breast Center, Smilow Cancer Hospital, New Haven, Connecticut, also offered her perspective on this Dutch study. “The fact that these findings fly in the face of randomized controlled trials makes me wonder about the unmeasured confounding factors.” She continued: “For example, the breast-conserving therapy group comprised younger women with more favorable tumor characteristics. The Dutch investigators did not control for comorbidities. I wonder how these factors would affect overall survivors. They may make mastectomy look worse. Also, it is very possible that patients who chose mastectomy had multifocal or multicentric disease. And there are other factors that are not measured that could predispose patients to choose one type of surgery over another.”
Dr. Chagpar noted that she would like to see the final manuscript of this study, where presumably the authors would discuss factors such as additional therapy, HER2 status, and other predictors of poor biology. “Questions remain about selection bias, and I hope the manuscript will address those,” she added.
Another question raised by Dr. Chagpar was whether the omission of radiation therapy for women in the mastectomy group might make survival in mastectomy look worse? “Patients who had mastectomy had no radiation therapy, yet we know that mastectomy plus whole-breast irradiation improves survival in node-positive disease,” she explained.
“We need to be cautious about interpreting these results. Physicians and patients should look at these data in the context of evidence from other randomized trials to make the right decision for them. There is no question that breast-conserving therapy is a good option for them. Whether it is a better option [than mastectomy] remains unanswered by this study,” Dr. Chagpar concluded. ■
Disclosure: Dr. Arteaga received consulting fees from Roche, Monogram (LabCorp), AstraZeneca, Novartis, Genentech, and Susan G. Komen. Dr. Chagpar reported no potential conflicts of interest.
Breast-conserving therapy (lumpectomy plus radiation therapy) appears to improve 10-year overall survival for women with early breast cancer compared with mastectomy, according to a very large population-based study from the Netherlands.1 However, the study raises more questions than it answers,...