Here are some possibilities.
- It's possible that you have DPD inhibition (genetic or chemically induced) which makes 5FU more potent, where lower doses act like higher doses in other people.
- It is possible that you have toxicity associated with folic acid or some drugs. Toxicity means it harms you, often much more than it harms the cancer. Many americans are exposed to high (any) amounts of folic acid that they process poorly (vs natural type folates) and that extraneous folic acid really bites them with 5FU drugs.
There are common drugs and nutrients that may enhance the performance of 5FU drugs, particularly of people with associated characteristics or markers, often common in CRC patients or the general population.
The nutrients may also have benefits that ameliorate the side effects of chemo and/or cancer.
My wife took cimetidine for many years based on her CA199 and CSLEX1 markers. Although aspirin has a cancer marker, we just applied it baby aspirin style. Enriched flours/supplement borne folic acid almost knocked her off chemo; natural folates (and other nutrients) in liver (spread) helps, -ed her a lot while on chemo. Based on various clinical and research papers, lab tests and markers, I believe the menatetrenone human form vitamin K2, vitamin D3, IV vitamin C, PSK and WGP both improved her general health and improved her cancer inhibition. These have companion or targetable markers. Sometimes they may need companion nutrients for common deficiencies or optimization.
We improved her chemo intensity enough to avoid other chemo drugs beyond a 5FU prodrug. We reduced her oral chemo's toxicity enough to use it daily for almost 8 solid years, without most of the common side effects.
The overall trend of papers that I have read with respect to stage 2 and 3 colon cancer patients is that some form of (personalized and especially useful) chemo intensity matters most, rather than long duration.
Conversely, after chemo, some nutrients or supplements may be useful long term to avoid or minimize conditions that encourage cancer cells growth, survival or induction.
watchful, active caregiver for stage IVb CC since early 2010. immuno"Chemo forever," for mCRC