Global survival and Lung cancer–Specific survival was consistently better for women with early breast cancer who were treated with breast preservation surgery (BCS) followed by radiation therapy (RT) compared to women who were treated with mastectomy (Mx) with or without RT, indicates a large Swedish cohort study.
“Women should not be strongly advised not to undergo more extensive surgery than necessary to remove the tumor; we should excise the tumor with clear margins, but [patients] do not benefit from additional removal of non-cancerous tissues, ”commented lead author Jana de Boniface, PhD, Capio St. Göran’s Hospital, Stockholm, Sweden.
“Women may experience a sense of security from having their entire breast removed, but they should be advised that a mastectomy does not result in a better prognosis, probably the opposite,” she said. Medscape Medical News in an email.
There are also “benefits for quality of life, body image and social functioning that many women report if they keep most of their own body intact,” she added.
The study was published online on May 5 a Surgery JAMA
“The most important message of this study is that BCS is safe for our cancer patients and this confirms data from many prospective randomized trials that produce results that are at least as good as mastectomy,” commented Lisa Newman, MD , MPH, Weill. Cornell Medicine, New York City, who was the author of accompanying comment.
Breast cancer registry
For this study, de Boniface and colleagues collected data prospectively from the Swedish National Breast Cancer Registry on a total of 48,986 patients.
“We included all patients diagnosed with primary invasive breast cancer from January 1, 2008 to December 31, 2017 who underwent breast surgery,” the researchers explain.
The team took into account comorbidities and the education, income, and country of birth of the patients, as identified from various databases during the study interval.
The women were operated as follows:
59.9% underwent locoregional treatment with BCS with RT (BCS + RT);
25.3% underwent a mastectomy followed by RT (Mx + RT);
4.7% underwent mastectomy without RT (Mx-RT).
The mean follow-up was 6.28 years.
The authors note that just over a third (35.2%) of the deaths that occurred during follow-up were due to breast cancer. At 5 years, 91.1% of patients were still alive; the specific survival rate for breast cancer was 96.3%.
However, the specific survival rate of breast cancer was 66% worse among women who had MX + RT compared to those who had BCS + RT (risk ratio). [HR], 1.66).
Overall survival was 79% worse after MX-RT compared with BCS + RT (HR, 1.79), after adjustment for tumor characteristics, treatment, demographics, comorbidity, and socioeconomic background. (It is well established that mastectomy is performed more frequently in women with lower socioeconomic status and in women with comorbidities, De Boniface commented.)
“Honestly, we would have hoped that comorbidity and socioeconomic status, which are factors affecting treatment choice, would have abrogated any difference in survival between surgical groups, but to see that this is not really the case is disconcerting and highly interesting, although I have not yet found any clear causal relationship, “de Boniface noted.
Seeing that really isn’t the case is puzzling and very interesting.
He also noted that most women have the option of undergoing BCS, even women with large tumors; it has been shown that they can also be treated with BCS safely.
“It is surprising that extensive breast surgery is more common in positive lymph node diseases despite its suitability for breast preservation, indicating a safety error, probably from both the patient’s and the doctor’s point of view,” the authors note.
“This report further questions the practice of offering mastectomy to patients who are suitable candidates for breast preservation,” they conclude.
Role of RT
In his commentary, Newman writes that these “fascinating results … challenge the wisdom of prematurely abandoning radiation after BCS for clinically early-stage disease.”
Commenting more on Medscape Medical News, noted that postmastectomy RT was routinely administered to patients with higher-risk mastectomy (i.e., patients with positive lymph node disease), so the outcomes of these high-risk patients cannot be compared based on whether RT was administered or not.
Similarly, radiation was not given to mastectomy patients with favorable biology (only 3.5% of T1N0 mastectomy patients received RT), so we cannot compare the results in these patients with early-stage mastectomy. depending on whether or not radiation was administered, “he added. .
In addition, patients who underwent BCS were excluded from the analysis if they did not receive RT, suggesting that physicians may speculate that RT contributed to the survival advantage of the BCS group.
However, that doesn’t mean RT would definitely explain the survival advantage in this cohort, he said.
“Ongoing studies evaluating the omission of RT as another strategy to de-escalate breast cancer treatment will need to be evaluated in the context of these data. [that] suggest a possible radiation survival benefit, “Newman acknowledged.
De Boniface and his co-authors and Newman have not revealed any relevant financial relationship.