Reoperation rates following breast-conserving surgery for early invasive breast cancer decreased after Society of Surgical Oncology and ASCO released a new guideline on adequate margins, according to results of a retrospective study published in American Journal of Surgery.
The declines included rates of reoperation among patients with pathologically negative margins — the guideline’s target population.
“The guideline states that if a tumor does not touch the inked portion of tissue, reoperation may not be warranted,” Alex Monaghan, second-year student in the southern medical program at University of British Columbia Okanagan, said in a press release. “Further surgery can lead to increased risk [for] medical complications and worsened cosmetic effects, without any evidence of prolonged survival or decreased cancer recurrence.”
Breast-conserving surgery is the current standard of care for patients with early-stage invasive breast cancer.
In 2014, the “no tumor on ink” guideline was released to help better define margin statuses, which are important in determining whether the patient needs reoperation.
Monaghan and colleagues studied the effect of the new guideline on reoperation rates following breast-conserving surgery by retrospectively reviewing British Columbia Cancer Agency regional hospital records of 523 women from the pre-guideline period (February 2011 to February 2014), when physicians used a 1-mm to 2-mm standard for negative margins, and 589 women from the post-guideline period (August 2014 to March 2017).
Because all regional hospitals did not implement the new guideline on a particular date, researchers excluded women who underwent surgery within 3 months of the hard-copy guideline being published.
More than 60% of women in each group were aged 55 to 74 years, although the post-guideline group had a larger proportion of women aged 65 to 74 years than the pre-guideline group. (37.7% vs. 30%). Otherwise, women in the groups had similar clinical and pathological characteristics. About 89% of women in the pre-guideline group and 86% in the post-guideline group had invasive ductal carcinoma.
Results showed a significantly lower likelihood of reoperation in the post-guideline period than the pre-guideline period (OR = 0.28; 95% CI, 0.15-0.51), with an unadjusted decrease of 3.89% in the overall reoperation rate.
Reoperation rates declined in the post-guideline period specifically among patients with close (OR = 0.17; 95% CI, 0.07-0.4) or negative (OR = 0.2; 95% CI, 0.05-0.77) margin status. The odds of reoperation did not change after introduction of the guideline among patients who had positive margins.
Women aged 74 years or older appeared less likely to undergo reoperation than women aged 45 years or younger (OR = 0.12; 95% CI, 0.03-0.77).
The study’s retrospective nature and low number of events served as limitations. Researchers also noted the risk for response bias.
Still, Monaghan and colleagues noted that it is encouraging to see rates of reoperation drop as a result of the new guideline.
“The research shows how the guideline has been adopted by community surgeons across the [British Columbia] Interior,” Monaghan said. “Patients can avoid potential surgical complications, added stress and the cosmetic effects. In addition, health care costs are reduced as a whole.” – by John DeRosier
Disclosure s : The authors report no relevant financial disclosures.