Breast cancer patients eligible for breast conservation surgery (BCS) are opting for mastectomy, breast reconstruction, and bilateral mastectomy in increasing numbers, US researchers have shown in one of the largest studies on the topic to date.
Confirming the results of several recent investigations, they found that the greatest increases in mastectomy rates during the past 2 decades were seen in women with node-negative and in situ tumors.
The study was published online on November 19 in JAMA Surgery.
"I do think it's important for patients and providers to be aware of this," lead researcher Kristy L. Kummerow, MD, of Vanderbilt University Medical Center, Nashville, Tennessee, told Medscape Medical News.
"We know that there is significant variation within our own country, and there's also variation in the United States compared to other countries. And anytime there's variation, it suggests that there may be opportunities to improve."
Dr Kummerow explained that several decades ago, patients with early-stage breast cancer underwent a radical operation involving removal of the entire breast, the underlying muscle, and the overlying skin. However, trials published in the 1980s demonstrated that BCS, involving lumpectomy and radiation, achieved equivalent oncologic outcomes.
"Our National Institutes of Health issued a consensus statement supporting breast conservation surgery for early breast cancer in 1990, and we saw a significant decline in performance of mastectomy for early breast cancer after that occurred," she said.
"However, it appears that the rates were starting to increase in the mid-2000s, and this has been demonstrated in several prior regional studies and some smaller national studies."
Dr Kumerrow continued: "We noted that it also appeared to be occurring in our own facility, and wanted to look at whether this trend was borne out on a national level using the largest dataset we have of patients treated in the United States for early-stage breast cancer."
The team examined data from the National Cancer Data Base on 1,216,820 women with primary breast cancer who underwent resection of the primary tumor between 1998 and 2011. Of those, 64.2% underwent BCS, and 35.5% had mastectomy.
During the study period, the proportion of women eligible for BCS who underwent mastectomy increased from 34.3% to 37.8% (P < .001 for trend). Multivariate analysis indicated that the odds of undergoing mastectomy increased by 34% in 2011 relative to 2003, at an odds ratio (OR) of 1.34.
Mastectomy was more likely to be performed in younger women, regardless of tumor size, and there was a strong association between mastectomy and tumor size >2 cm in older women.
Looking further into the data, the researchers found that women with clinically negative nodes had an OR of mastectomy in 2011 of 1.38 vs 2003; the OR of mastectomy for women with in situ tumors was 2.05.
The proportion of mastectomy patients who had breast reconstruction increased from 11.6% in 1998 to 36.4% in 2011.
Rates of bilateral mastectomy for unilateral disease also increased during the same period, from 1.9% to 11.2% among women eligible for BCS and from 5.4% to 29.7% among women undergoing mastectomy for unilateral disease.
Dr Kumerrow pointed out that the results are robust, inasmuch as their multivariate model took into account factors such as patient age, comorbid conditions, the type of facility, and the region of the country in which the patient was treated.
However, the question as to the reasons underpinning the increase in mastectomy rates remains. "I don't think we have a good answer to that at this point," Dr Kummerow stated.
"Our study was not able to address that specific question because we used retrospective data, and we don't have individual-level data to inform how individual decisions are made between patients and providers about their personal cases."
"There has been some work at other institutions suggesting both patient and provider factors, but, to be honest, I don't think we really have a good sense from the studies that have been done so far of what is driving this or how these factors vary in their degree of influence in different populations of women," she said.
Showing a Trend
There may be identifiable reasons for the trend, suggested Michael E. Zenilman, MD, from Johns Hopkins Medicine, Baltimore, who wrote an accompanying commentary.
Speaking to Medscape Medical News, he said: "With the increase in quality and expertise in breast reconstruction, reconstructions after mastectomy have gotten to the point where they are really wonderful, and the cosmetic results are pretty good. Now breast reconstructions are increasing, and in order to do a breast reconstruction adequately, sometimes you have to do a mastectomy."
"So I think what's going on is the mastectomy rate is going up because the breast reconstruction rate is going up."
He continued: "The issue then is, Okay, is this a good thing or not? I'm not so sure it's necessarily something that's good or not good."
"I think it's just a fact of what a trend is, and the fact that the mastectomies are going up is not a bad thing. It means that plastic surgery rates are getting better, and it's actually the function of women having more choices."
Dr Zenilman explained: "If you think about it, women now have three choices: They can have a mastectomy with no reconstruction; a lumpectomy, and depending on the extent of the lumpectomy, they can do plastic surgery on that; or do formal mastectomy with reconstruction."
"I think the balance is going to be then between how much surgery the patients really want, because ultimately, the more extensive reconstructions require more extensive surgery, and those aren't necessarily without complications."
The decision as to whether to undergo BCS or mastectomy may also be one of patients wanting to be "better safe than sorry," despite the fact that more extensive surgery does not necessarily offer clinical benefit.
"Doing mastectomy for a phase I cancer...may not be the right operation to 'cure the disease,' because it's already been shown that for mastectomy vs lumpectomy with radiation, there's no difference for stage I and stage II breast cancer," Dr Zenilman said.
"So I think there is some irrational fear going with patients who think that the bigger operation is better."
This fear may also underlie recent data suggesting that mastectomy patients are undergoing contralateral mastectomy despite not having a significant risk for contralateral disease.
As Dr Zenilman said: "The real question is, What do you tell patients when they are BRCA negative and they have an inordinate fear that they are going to get breast cancer, because they are at higher risk but are not necessarily at the higher risk where a mastectomy prophylaxis is really indicated?"
Summarizing, Dr Kummerow and Dr Zenilman agreed that the trend in mastectomy rates should be monitored.
"We obviously don't know how this will change in the future, whether the trajectory will continue or if levels will flatten out," Dr Kummerow stated.
"Understanding that this is occurring and continuing to reassess the current standards that are established by the national accreditation program for breast centers, and where those standards may be inadequate or may need to be looked at further, could be incredibly helpful," she added.
Most importantly, patients need to be informed about their options. "If you are going to have a major operation, you should understand that these major operations include risks, and breast conservation therapy is not as big an operation as major reconstruction," Dr Zemilman said.
He concluded: "As long as the patients are understanding what's going on and the surgeons are giving the right therapy, then these are great choices for these patients at a time that is very difficult."
Dr Kummerow has reported no relevant financial relationships. Dr Zenilman is a consultant for Champions in Oncology. No other authors have reported any relevant financial relationships.
JAMA Surgery. Published online November 19, 2014.
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Cite this: Mastectomy Rates on the Increase in Early Breast Cancer - Medscape - Nov 19, 2014.
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