(CBS News) A new study out of Duke University suggests less invasive treatment for early stage breast cancer may increase survival. The Duke research team analyzed data from 112,154 women diagnosed with Stage 1 or Stage 2 breast cancer between 1990 and 2004. 61,771 of the women received lumpectomy and radiation and 50,383 had mastectomy without radiation.
The researchers found that within three years of diagnosis, breast cancer patients who underwent lumpectomy and radiation had higher survival rates than those who chose mastectomy. The study was based on observational data, so it hints at an association but does not necessarily prove that less invasive treatment is more effective than a mastectomy in the early stage of breast cancer.
Dr. Rache Simmons, the Chief of Breast surgery at Weill Cornell Medical College, said she "reserves skepticism" on the study, which suggests that "lumpectomy plus radiation actually has survival advantage over mastectomy." She explained Monday on "CBS This Morning," that the study was retrospective, and that retrospective studies "always have an element of bias."
Simmons discussed the results of the study, which indicated that "The main advantages were in patients were actually estrogen-receptor positive and an older age group, over 50."
"Well those are the best breast cancers anyway, the best prognostic indicators. So it may be there's a bias in the study to suggest a better outcome in those patients," Simmons said, describing the generally more favorable prognosis for patients with estrogen receptor-positive tumors.
Turning to the two treatment paths used in the study, she said, "We've know for a long time they are equal. It's counter-intuitive to suggest there's actually an advantage of survival unless there's a bias in the study."
Simmons suggested that despite the results of the study, patients should still "talk to your surgeon about what's appropriate for you. Certainly some patients where mastectomy still is a better choice."