SCOTTSDALE, ARIZ. – In breast conservation surgery with whole-breast radiation, costs and the number of re-excisions performed at a single institution dropped after the implementation of 2014 consensus guidelines on excision margins.
The guidelines, created by a multidisciplinary margins panel convened by the Society of Surgical Oncology and the American Society for Radiation Oncology recommend “no ink on tumor” as an adequate margin in cases of invasive carcinoma.
The guidelines sought to reduce costs and re-excision rates and improve cosmetic outcomes. The results of the study carried out at the University of Louisville suggest that the guidelines may be successful in achieving these goals. The reduced need for re-excision is a key point. “That’s very traumatic for the patient. With this consensus, we were able to decrease that, improve patient satisfaction, and decrease the cost,” lead author Nicolás Ajkay, MD, assistant professor of surgery at the University of Louisville School of Medicine, said in an interview.
Dr. Ajkay presented the results of the study at the annual meeting of the Western Surgical Association.
“Surgeons need to be aware of the guidelines, and if the margin is close, they need to be in multidisciplinary discussions with other breast cancer experts to determine which patients would benefit from going back to the operating room,” he said.
The researchers examined the experiences of 237 patients with stage I or stage II invasive carcinoma who had a partial mastectomy. Of these patients, 126 underwent the procedure before the university incorporated the guidelines in March 2014 (PRE), while 111 were seen after that date (POST). The study excluded those who were diagnosed by excisional biopsy and those who were treated with neoadjuvant chemotherapy.
Per-patient operative costs went down on average after the guidelines were implemented ($4,247 vs. $5,465; difference, $1,218; P less than .001). The estimated savings for the entire POST cohort of 111 patients was approximately $135,000.
Patient satisfaction improved as measured by the breast satisfaction domain of the BREAST-Q survey tool (77/100 vs. 61/100; P = .03).
A multivariate analysis showed that the implementation of the consensus statement predicted lower re-excision rates (odds ratio, 0.17; 95% confidence interval, 0.08-0.38; P less than .001) as well as lower operative cost per patient (cost greater than $5,465 OR, 0.14; 95% CI, 0.07-0.30; P less than .001). Guideline implementation did not, however, predict decreased total resection volume, or probability of conversion to mastectomy.
Perhaps because diagnostic methods have improved over time, there were some significant differences between the two populations. The PRE group had a larger median tumor size (1.5 cm vs. 1.1 cm; P less than .001), and a lower proportion of the PRE group was diagnosed as stage I (62% vs. 77%; P = .005). The PRE group also had significantly larger initial resection volume (69.3 cm3 versus 47.1 cm3; P = .02), higher selective margin volume (50.0 cm3 vs. 11.3 cm3; P less than .001), and a larger final resection volume (81.0 cm3 vs. 51.5 cm3; P = .05). Additional selective margin resection was less frequent in the PRE group (76% vs. 41%; P less than .001).
Those differences may confound the findings, since outcomes might have been expected to improve anyway due to improvements in care.
One member of the audience asked whether the guidelines might boost rates of cancer recurrence. It’s too soon to tell, according to Dr. Ajkay, who said that researchers will need at least 4 or 5 years of clinical experience to make that determination. But he is optimistic. “Even though we’re excising less, I would predict we will not see an increase in recurrence, because adjuvant therapy is getting significantly better, and adjuvant therapy reduces the risk of recurrence just as margin re-excisions do,” he said.
The study received no external funding. Dr. Ajkay reported having no financial disclosures.