5-fluorouracil with oxaliplatin and/or irinotecan for advanced sinonasal intestinal-type adenocarcinoma (ITAC).

Introduction: Sinonasal intestinal-type adenocarcinoma (ITAC) is a rare tumor, typically found in the ethmoid or upper nasal cavity. There is no standard systemic treatment for metastatic/locally advanced disease ineligible for upfront surgery or radiotherapy.

Methods: Patients treated between 2015 and 2021 in our institution with a fluoropyrimidine plus oxaliplatin and/or irinotecan for advanced ITAC were retrospectively assessed for overall survival (OS), progression-free survival (PFS) and tumoral responses.

Results: Six patients without meningeal involvement received chemotherapy (three FOLFOX, two FOLFIRI, one FOLFIRINOX). All achieved a response, including those with brain extension. Median PFS with FOLFOX and FOLFIRI was similar (6.0 months, 95%CI 5.8-NR; 5.8 months, 95%CI 5.8-NR respectively). Three patients had meningeal involvement with meningitis symptoms and received first-line therapy. All had rapid disease progression (median PFS 1.2 months, 95%CI 1.0-NR) DISCUSSION: FOLFOX, FOLFIRI or FOLFIRINOX appear to have anti-tumor efficacy for metastatic or locally advanced unresectable ITAC, except in cases of carcinomatous meningitis. These regimens require further evaluation.