P39.02 Does Neo-Adjuvant Chemotherapy Help in Locally Advanced Thymic Maliganancy?

Abstract

Neoadjuvant chemotherapy is used to downsize thymic malignancies and improve R0 resection. However, there is no level I evidence for this. Here, we present our experience with neoadjuvant chemotherapy for locally advanced thymomas from a tertiary cancer center in India. This is a retrospective analysis of a prospective database. (Jan05 to Dec20) We included the following patients receiving neoadjuvant chemotherapy: Unresectable: Involving aortic arch / branches, main pulmonary trunk, heart Borderline Resectable: Involving SVC, brachiocephalic vein, main PA / branches, lung parenchyma Volumetric analysis was done using “ellipsoid” method for tumor volumes. Survival analysis was performed with Kaplan Meier method. Forty-one patients received neoadjuvant chemotherapy. At presentation, 16(41.5%) were unresectable, 25(56.1%) were borderline resectable. Most common structures at risk were arch aorta and branches(31.7%), SVC(24.39%) and main Pulmonary Artery(19.51%). Average tumor volume was 655.75cm3(90.45 – 4212.0) Good proportion of patients completed the planned chemotherapy(90.24%). However, only 56.1% came up for surgery. 4 progressed, 2 died due to chemotherapy related toxicity, 3 refused surgery and 9 remained unresectable. 12.5% of unresectable tumors and 44.0% of borderline tumors underwent R0 resection. 3/41 patients had complications Clavien-Dindo 3b and above with 1 mortality. The best volume reduction was seen in thymoma B2(54.84%) and thymic carcinomas(42.02%). At a median follow up of 34 months, 3 patients had local and 2 had systemic recurrences. Patients with R0 resection did significantly better than those with R+ resections or found unresectable.(p=0.03) R0 resectability remains the most important predictor of survival in thymic neoplasms. Neoadjuvant chemotherapy introduces the possibility of R0 reaction in unresectable tumors and should be strongly considered. In borderline resectable tumors, neoadjuvant chemotherapy affords a higher rate of R0 resection with less complex resections and minimal morbidity. This finding should be further evaluated in prospective multi centric studies