Epidemic of Breast Cancer Resurgeries in the US

Nick Mulcahy

August 05, 2015

CORRECTED // The rate of reoperation for breast cancer in the United States "can and should be reduced" because there is an "epidemic" of resurgeries, according to an editorial published in the August 6 issue of the New England Journal of Medicine.

The exact dimensions of the problem are difficult to pinpoint, say editorialists Hiram Cody III, MD, and Kimberly Van Zee, MD, from the Memorial Sloan Kettering Cancer Center in New York City.

Anywhere from 10% to 50% of lumpectomies in the United States will result in another surgery, they report.

The resurgeries are needed because of "close or positive margins" — in which some tumor is still found on postsurgical pathologic review in the otherwise tumor-free margins of the removed breast tissue. The positive margin suggests that some tumor was left behind in the body cavity, and frequently leads to a second surgery.

These extra surgeries, or re-excisions, have "considerable" cosmetic, emotional, and financial burdens, Drs and Kimberly Van Zee point out.

Even a modest 10% reduction in the re-excision rate would prevent reoperation in 10,000 to 20,000 of the 180,000 American women who undergo lumpectomy annually in the United States, they assert.

So, how can physicians remove breast tumors more successfully and avoid the dreaded positive margin and resurgery?

One approach is "cavity shaving," whereby the surgeon, after removing the tumor tissue, goes back and further trims the face of the tissue cavity in the breast.

Routine cavity shaving has been practiced at Memorial Sloan Kettering since 2008, the pair reports, but the approach has only been supported by retrospective data.

However, top-level evidence has now shown that cavity shaving reduces reoperation after lumpectomy. Results from a clinical trial comparing shaving with no shaving — initially presented in May at the annual meeting of the American Society of Clinical Oncology (ASCO) — have now been published in the August 6 issue of the New England Journal of Medicine.

"Cavity shave is not a new procedure...but this is the first randomized trial comparing it to another method and showing that it's better," Dr Cody said emphatically in an email to Medscape Medical News.

In the trial, 235 breast cancer patients with stage 0 to III disease were randomized to receive additional circumferential shaving of the cavity margins or no shaving. Median age of the patients was 61 years.

After a median follow-up of 22 months, patients in the shave group had a significantly lower rate of positive margins than those in the no-shave group (19% vs 34%; P = .01). For invasive cancer, positive margins were defined as tumor touching the edge of the specimen; for ductal carcinoma in situ (DCIS), they were defined as tumor within 1 mm of the specimen edge.

The re-excision rate was also significantly lower in the shave group than in the no-shave group (10% vs 21%; = .02).

The lead investigator of the trial, Anees B. Chagpar, MD, from the Yale Cancer Center in New Haven, Connecticut, called the results eye-opening.

"Before we embarked upon the trial, I was not an advocate of doing routine cavity shave margins," Dr Chagpar said at the ASCO meeting, as reported by Medscape Medical News. But the new data have changed her "personal practice and the practice of many surgeons at Yale."

Importantly, the investigators found that cosmetic outcomes and wound complications were comparable in the two groups, even though 50% more tissue was removed in the shave group.

However, Dr Cody and Dr Van Zee suggest that the cosmetic results, which were self-reported by study patients at their first postoperative visit, might not hold up.

Seroma will fill the excision cavity in the short run, and might mask the effects of taking out more tissue with shaving, they say, adding that longer follow-up is needed.

The study also provides some potentially important insights about DCIS or DCIS involvement with an invasive tumor.

"Positive margins were more common in tumors that had a DCIS component (32% vs 12%). Even in a multivariate analysis controlling for other factors, the size of the DCIS component was significantly associated with positive margins," said Dr Cody. "This suggests that cavity shave may be particularly useful for tumors with a DCIS component, and is a subject for further study."

Breast-conserving surgery (lumpectomy) is about as good as it is going to get in terms of local control, say the editorialists. The 10-year rate of local control is "quite low" (6% to 9%), and modifications to treatment are not likely to improve this.

Thus, lumpectomy can be most improved by reducing reoperation, they assert.

A "good starting point" is having a consensus definition of margins, which has been plagued with a range of parameters. But the recent Society of Surgical Oncology/American Society for Radiation Oncology guideline indicates that "no tumor on ink" is adequate, say Drs Cody and Van Zee. The guideline was published in 2014, as reported by Medscape Medical News.

Dr Cody said he also believes that a multidisciplinary effort is required to reduce the rate of reoperation.

"Radiologists, surgeons, and pathologists should do whatever they can to minimize the rates of positive margins and of re-excision. Cavity shave is one way to do this, but other methods have reported equally good results," he said.

Notably, the American Society of Breast Surgeons recently convened a multidisciplinary consensus panel and developed a "toolbox" of techniques to reduce re-excision rates. That toolbox was published online July 28 in the Annals of Surgical Oncology.

N Engl J Med. 2015;373:503-510, 568-569. Abstract, Editorial

Editor's note: An earlier version of this story stated incorrectly indicated that Dr Chagpar was male; in fact, she is female.

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