Abstract 16787: Calcium Channel Blockers and Nitrates in 5-FU Vasospasm

Abstract

Introduction: Coronary vasospasm is a side effect of 5-FU (fluorouracil). Beyond switching chemotherapy regimens, there are no established treatments for vasospasm. Limited data exist regarding the efficacy of calcium channel blockers (CCBs) and/or nitrates with 5-FU vasospasm. Methods: We conducted a retrospective analysis of all patients at Massachusetts General Hospital who were diagnosed with 5-FU coronary vasospasm. As part of institutional practice, those referred to cardio-oncology receive pre-treatment with vasospasm therapies (either combination [nitrates and CCBs] or single agent therapy [nitrates or CCBs]) prior to re-challenge with 5-FU. Our primary outcomes were the safety and effectiveness of this cardiac pre-treatment approach. Results: Among 7,711 patients who received 5-FU from Jan 2001 to Jul 2017, 86 (1.11%) developed coronary vasospasm. Overall 64 patients continued to receive subsequent 5-FU, while 22 stopped. Of the 64 who continued, 60 were referred to cardio-oncology and prescribed CCBs and/or nitrates prior to subsequent 5-FU. Of these 60, 52% (31/60) received both nitrates and CCBs, 20% (12/60) received CCBs alone, and 28% (17/60) received nitrates alone, while 4 continued 5-FU without cardiac pre-treatment. Chest pain (without a myocardial infarct) recurred in 11.7% (7/60) among those who received cardiac pre-treatment vs. 50% (2/4) among those who did not (P=0.033). When those who stopped were compared to those who continued 5-FU (with cardiac pre-treatment), the cardiovascular profile, stage and type of cancer were similar. As compared to patients who stopped 5-FU, those who continued after nitrates/CCBs had improved progression free (HR 0.56, P=0.076 [95% CI 0.30-1.06]) and overall (HR 0.29, P<0.001 [95% CI 0.15-0.57]) survival. Conclusion: In the largest report of 5-FU associated vasospasm, re-challenge after pre-treatment with CCBs and nitrates was safe and effective, thus allowing patients to receive additional 5-FU.