A genetic test could stop some patients from overdosing on a chemotherapy drug, but only 3% of oncologists are testing patients, KFF Health News reported March 26.
Each year, more than 275,000 cancer patients in the U.S. are infused with fluorouracil, known as 5-FU, or take a nearly identical drug in pill form called capecitabine. Not all patients have the genetic code that allows the body to metabolize the drug, and an estimated 1 in 1,000 patients who take it are killed, and 1 in 50 are severely sickened or hospitalized. 5-FU has been around since the 1950s.
There's a test that can detect the gene deficiency, but a recent survey found only 3% of oncologists routinely order the test before dosing patients.
So far, there are no cancer treatment guidelines that recommend preemptive testing.
The FDA added a new warning label about the lethal risks of 5-FU on March 21; however, the agency does not endorse the 5-FU toxicity tests because it has not reviewed them.
A small number of systems, professional groups and advocates are pushing for the endorsement of routine testing. Most insurers currently cover the test, whichMedicare also reimburses for $175.
A Cancer Network panel said that not everyone with a risky gene variant is sickened by the drug and that lower doses could rob them of a cure or remission, according to KFF. Most of the panel said they have never witnessed a 5-FU death; however, multiple states have settled lawsuits surrounding 5-FU deaths.
A single death caused by a 5-FU overdose at Boston-based Dana-Farber Cancer Institute in 2021 spurred the system to change its procedures. The patient's daughter wrote to the center's chief quality officer, urging routine testing. The hospital quickly adopted a testing system that covers more than 90% of prospective 5-FU patients, and about 50 patients with risky variants were detected in the first 10 months, the center told KFF.
Dana-Farber uses a Mayo Clinic test that searches for eight potentially dangerous variants, and Veterans Affairs hospitals look for 11 variants, but "most others check for only four variants," according to the report.