Although the introduction of immune checkpoint inhibitor (ICI) therapy has led to improved survival rates for metastatic melanoma, the treatment is associated with complex disease response patterns. Indeed, ICI therapy results in a complete response in only 15 to 20 percent of cases. Select patients who develop a mixed response following ICI therapy may receive significant benefit from surgical resection, according to a retrospective study published in April 2019 in the Journal of Surgical Research.

The study is one of the first to examine the role of surgery in patients with melanoma who have been treated with ICI therapy, says the study’s senior author, Georgia Beasley, MD, MHSc, a surgical oncologist at Duke who specializes in melanoma. “There has been a lot of discussion around using surgery to clear up residual tumor following ICI, but this is one of the first reports of a defined case series,” she explains.

This kind of study is important, she adds, because treating these patients can be complicated: “A lot of patients with metastatic melanoma have been on ICI therapy. Some of their lesions may shrink in response, others may not. Even within one lesion, there can be a mixed response to a therapy. Therefore, surgery can be used to clear the patient of all known disease.”

To examine outcomes in patients who have undergone ICI therapy followed by surgical resection, the researchers queried two databases—the James Cancer Registry at the Ohio State University Comprehensive Cancer Center-James Cancer Hospital and the Duke Enterprise Data Unified Content Explorer at Duke University Hospital. A total of 25 patients were included in the analysis, and key outcome measures included safety, progression-free survival, and overall survival.

Surgery after ICI therapy was well tolerated in all patients, and there were no surgical complications. Overall, patients benefitted from surgery, with 92% of patients surviving at a 14-month follow-up. Of the 68 percent of patients with oligoprogressive disease (i.e., mixed response to ICI therapy), 70.6 percent maintained no evidence of disease (NED) 20.4 months after surgery. In fact, the authors noted, surgical resection remains the only definitive treatment with the potential to help patients with a mixed response achieve NED.

“The next steps are informing patients that multidisciplinary care is truly essential to optimize treatment and may require both systemic therapy and surgery,” Beasley says. “ICI does not seem to impact surgical outcomes; thus, the two can be used in combination.”