Resection of residual disease after isolated limb infusion (ILI) is equivalent to a complete response after ili-alone in advanced extremity melanoma

Background: Isolated limb infusion (ILI) is a limb-preserving treatment for in-transit extremity melanoma. The benefit of resecting residual disease after ILI is unclear. Methods: A multi-institutional experience was analyzed comparing patients who underwent ILI plus resection of residual disease (ILI + RES) versus ILI-alone. Results: A total of 176 patients were included, 154 with ILI-alone and 22 with ILI + RES. There were no differences between the groups with respect to gender, age, extremity affected, or time from diagnosis to ILI. All surgical resections were performed as an outpatient procedure, separate from the ILI. Within the ILI + RES group, 15 (68 %) had a partial response (PR), 2 (9 %) stable disease (SD), and 5 (23 %) progressive disease (PD). The ILI-alone group had 52 (34 %) CR, 30 (19 %) PR, 15 (10 %) SD, and 46 (30 %) PD. Eleven (7 %) ILI-alone patients did not have 3-month response available for review. Evaluating overall survival (OS) from date of ILI, the ILI-alone group had a median OS of 30.9 months, whereas the ILI + RES group had not reached median OS, p = 0.304. Although the ILI + RES group had a slightly longer disease-free survival (DFS) compared to those with a CR after ILI-alone (12.4 vs. 9.6), this was not statistically significant, p = 0.978. Within the ILI + RES group, those with an initial PR after ILI had improved DFS versus those with SD or PD after ILI, p < 0.0001. Conclusions: Resection of residual disease after ILI offers a DFS and OS similar to those who have a CR after ILI-alone. It may offer a treatment strategy that benefits patients undergoing ILI.