22.9% of breast cancer patients who undergo partial mastectomies need further operations to remove more tissue, researchers reported in JAMA (Journal of the American Medical Association). The authors, from Michigan State University, added that rates of reexcision vary considerably between surgeons and clinics/hospitals; this variation does not appear to be caused by patients’ clinical characteristics.

“Excision” means the surgical removal of something, which in this text means a tumor. “Reexcision” means additional surgery in the same area.

Current health care reforms that are taking place in the USA call for more doctor and hospital transparency and accountability of patient outcomes.

The authors wrote:

“Breast-conserving therapy, or partial mastectomy, is one of the most commonly performed cancer operations in the United States. Currently, there are no readily identifiable quality measures that allow for meaningful comparisons of breast cancer surgical outcomes among treating surgeons and hospitals.”

A surgeon’s aim when performing a mastectomy is to achieve adequate surgical margins – there should be a rim of normal tissue around the excised tumor so that there is no cancerous tissue left behind. Additionally, the cosmetic appearance of the breast should be maintained as much as possible.

If clear margins are not achieved after the initial surgery, further surgical intervention will be required. Additional operations cause significant physical, emotional, mental and economic stress for patients, and also delay vital supplemental therapies.

The authors wrote:

“Thus, the effect of reexcision on altering a patient’s initial treatment of choice is significant.”

Laurence E. McCahill, M.D., and team set out to measure what the reexcision rates are across surgeons and hospitals in the USA that treat patients with comparable clinical conditions. They specifically looked at female patients with invasive breast cancer who underwent partial mastectomy across 4 institutions and 3 large health plans. They gathered data from various sources, including electronic medical records, outpatient records, and pathology archives.

Out of 2,206 women in their study, 2,220 had been recently diagnosed with invasive breast cancer and had breast-conserving surgery performed on them. Their average age was 62 years. 92.8% of them were non-Hispanic white.

Below are some highlighted findings from this study:

  • 22.9% (509) had additional surgery on the affected breast
  • 89.2% of those who had additional surgery underwent a single reexcision
  • 9.4% (48) of the additional surgery patients underwent 2 reexcisions
  • 1.4% (7) underwent 3 reexcisions
  • 8.5% (190) of them had a total mastectomy

The researchers wrote:

“Reexcision rates for margin status following initial surgery were 85.9 percent for initial positive margins [cancer cells at the edge of the removed tissue], 47.9 percent for less than 1.0 mm margins, 20.2 percent for 1.0 to 1.9 mm margins, and 6.3 percent for 2.0 to 2.9 mm margins.

For patients with negative margins [no cancer cells at the outer edge of the tissue that was removed], reexcision rates varied widely among surgeons (range, 0 percent – 70 percent) and institutions (range, 1.7 percent – 20.9 percent). Reexcision rates were not associated with surgeon procedure volume after adjusting for case mix.”

Reexcisions of positive margins varied among institutions from 73.7% to 93.5%. The authors believe that surgeons’ different training may be the cause, as well as variations on how data is interpreted in different regions.

In an Abstract in the journal, the authors concluded:

“Our study highlights the value of multicenter observational studies in demonstrating variability in health care across geographic regions and different health systems, with uniform data collection instruments. The long-term effect of this variability is beyond the scope of our study, but it is feasible that outcomes such as local recurrence and even overall survival could be affected by variability in initial surgical care.

Even in the absence of effects on local control, the wide level of unexplained clinical variation itself represents a potential barrier to high-quality and cost-effective care of patients with breast cancer. Continued comparative effectiveness research of breast cancer surgery requires further attention to better determine the association of initial surgical care with long-term patient outcomes.”

Steven J. Katz, M.D., M.P.H., of the University of Michigan. Ann Arbor, and Monica Morrow, M.D., of the Memorial Sloan-Kettering Cancer Center, New York, wrote:

“The article by McCahill et al underscores the challenge in developing surgical quality indicators for patients with cancer, especially for procedures with very low risk of major complications. While there is strong evidence that positive margins are associated with an increased rate of local recurrence, a substantial number of reexcisions are performed among patients with negative margins to obtain a more widely clear margin.

There is no consensus among surgeons and radiation oncologists as to what constitutes an optimal negative margin width because the question has not been addressed in prospective randomized trials. The observational design used in the McCahill et al study is valuable for illuminating the nature of potential quality gaps but cannot be used to inform the validity of candidate quality measures.”

Written by Christian Nordqvist