Omitting 5-FU Bolus May Reduce Side Effects in Patients with Advanced Gastrointestinal Cancers
September 2024
Findings from research published in the Journal of the National Comprehensive Cancer Network found that when the 5-fluorouracil (5-FU) bolus from combination chemotherapy treatments such as FOLFOX (Folinic acid, 5-Fluorouracil, Oxaliplatin), FOLFIRI (Folinic acid, 5-Fluorouracil, Irinotecan), or FOLFIRINOX (Folinic acid, 5-Fluorouracil, Irinotecan, Oxaliplatin), was removed, it helped to improve the tolerability of the chemotherapy treatment without reducing the treatment’s efficacy among patients with advanced gastrointestinal cancers.
Bolus chemotherapy: A single dose of chemotherapy given over a short period of time. It is usually given by infusion or injection into a blood vessel (National Cancer Institute)
When the 5-FU bolus was removed, patients experienced a lower risk of developing neutropenia (low white blood cell count) and thrombocytopenia (low blood platelet count) and had no significant negative impact of patients’ survival outcomes.
The study
The study included 11,765 patients who were enrolled in the Flatiron Health database. Patients with advanced colorectal cancer (73.7%), pancreatic cancer (13.7%) and gastroesophageal cancer (12.6%) who were diagnosed between January 2011 and May 2022 were included in the study.
Most patients (86.3%) received a 5-FU bolus as part of their first-line chemotherapy treatment, while 13.7% did not receive the bolus.
When the patients’ overall survival outcomes were assessed by cancer type, there were no significant differences between patients who received the 5-FU bolus compared to those that did not receive it.
Table 1: Overall survival (OS) by Cancer Type and 5-FU Bolus (received vs. not received)
| Cancer Type | Received 5-FU Bolus | Did not receive 5-FU Bolus |
| Overall survival (months) | ||
| Colorectal | 24.5 | 23.6 |
| Esophageal | 10.2 | 10.4 |
| Pancreatic | 9.5 | 8.9 |
Patients in the bolus group were more likely to experience neutropenia (low white blood cell count) within 2 weeks of treatment. Patients who received a bolus were also more likely to experience low platelet levels in the blood. The researchers conducted an analysis adjusting for the doses of oxaliplatin and irinotecan to assess whether these drugs were linked to the incidence of either neutropenia or thrombocytopenia, but the 5-FU bolus remained responsible for the increased risk of developing both conditions.
Conclusion
Prior to this study, there was no clear evidence to support that the 5-FU bolus in combination chemotherapy regimens added additional benefit to patients. This study demonstrates that among patients with advanced gastrointestinal cancers, removing the 5-FU bolus reduces side effects and costs without any negative impact on survival. This is a significant finding as it makes treatment more tolerable, particularly chemotherapy which tends to provoke a range of side effects in patients. More research will be required to validate these findings.
Peng C, Saffo S, Oberstein PE, et al. Omission of 5-Fluorouracil bolus from multidrug regimens for advanced gastrointestinal cancers: A multicenter cohort study. J Natl Compr Cancer Netw. Published online September 5, 2024. doi:10.6004/jnccn.2024.7029
New study in JNCCN supports chemotherapy option that reduces side effects for people with gastrointestinal cancers. News release. National Comprehensive Cancer Network. Published September 5, 2024. Accessed September 17, 2024.
