Retrospective comparison of the efficacy and the toxicity of standard and modified FOLFIRINOX regimens in patients with metastatic pancreatic adenocarcinoma

BACKGROUND: FOLFIRINOX stands a major breakthrough in the management of metastatic pancreatic adenocarcinoma (MPA). Nonetheless, significant side-effects have been reported using standard FOLFIRINOX. We aimed to compare survival outcomes, response rates and toxicity of patients treated with standard or modified FOLFIRINOX in MPA. METHODS: We included patients aged ≥18 years old, with pathologically confirmed MPA, treated with FOLFIRINOX in the first-line setting. Patients submitted to at least one cycle of full-dose FOLFIRINOX were grouped in the standard FOLFIRINOX group. RESULTS: Patients treated with standard FOLFIRINOX were younger and had less comorbidity. We observed no differences in overall survival or in progression-free survival between the two treatment arms. The only variable independently associated with OS was log10[neutrophil-to-lymphocyte ratio (NLR)]. Modified FOLFIRINOX was associated with a lower dose reduction rate, but a slightly increased incidence of severe toxicity. CONCLUSIONS: Modified FOLFIRINOX presents the same activity against MPA as standard FOLFIRINOX. We found no significant differences in toxicity, possibly due to patient selection and a higher dose reduction rate in the standard FOLFIRINOX arm. NLR stood as an important prognostic marker and further research is needed to comprehend its biological meaning in pancreatic cancer.