In the wake of the pivotal IDEA TRIAL, oncologists have shifted towards shorter adjuvant chemotherapy regimens for stage III colon cancer and a greater reliance on CAPOX (capecitabine plus oxaliplatin) instead of FOLFOX (oxaliplatin, 5-fluorouracil, and leucovorin), according to a review of 366 patients.
The international IDEA trial showed that, across almost 13,000 subjects, 3 months of treatment with either regimen was not inferior to 6 months, which was standard at the time for low-risk disease and often led to significantly less grade 2, but more neuropathy.
In high-risk patients (T4, N2), 3-year disease-free survival was almost identical between 3 months of CAPOX (64.1%) and 6 months (64.0%), but 3 months of FOLFOX was inferior to 6 months of FOLFOX (61.5% vs. 64.7%).
Oncologists paid attention, according to the new review, which was presented at the 2022 Gastrointestinal Cancers Symposium.
Overall, 16.3% of patients were prescribed CAPOX in June 2016, but before the study was published in the New England Journal of Medicine, the number rose to 66.8% by June 2020.
“We are using a lot more CAPOX in this country now, and it’s interesting we are doing that because the data aren’t quite there” yet for patients in the United States, said lead investigator Daniel Walden, MD, a hematology/oncology fellow at Mayo Clinic Arizona, Phoenix.
IDEA pulled data from six trials, but only one included U.S. patients and it did not permit CAPOX, only FOLFOX. As a result, the growing use of CAPOX in the United States is based on outcomes elsewhere, primarily Europe and Japan.
The problem, Dr. Walden said, is that U.S. patients don’t tolerate capecitabine as well as people in other countries because of the high intake of dietary folic acid, which is added to grains in the United States and interferes with capecitabine clearance.
He and his team are now looking into outcomes, particularly with CAPOX, in their U.S. cohort, which was pulled from Mayo Clinic campuses in Arizona, Minnesota, and Florida, with additional subjects from Emory and Vanderbilt Universities. “Hopefully,” data to support the shift to adjuvant CAPOX in the United States “will be here soon. I feel more confident prescribing 3 months of CAPOX for high-risk patients, seeing that more people do it than I would have thought,” Dr. Walden said. His study found a 25.9% adoption in June 2020, which was up from 1.3% in June 2016.
Among other findings, 78.3% of patients received 6 months of FOLFOX in June 2016, which fell to 17.3% 4 years later. There was a corresponding shift in 3-month courses of CAPOX, up from 7.4% to 67.5% over the same period.
By June 2020, low-risk patients were far more likely to receive 3 months of CAPOX (67.9%) than any other regimen.
Among high-risk patients, the number who received 6 months of FOLFOX fell from 86.6% to 47.8%, while the number who received 3 months of FOLFOX increased from 0.9% to 3.9%. Use of CAPOX for 6 months in high-risk patients climbed from 11.2% of patients to 22.4%.
There was no funding for the work, and Dr. Walden didn’t have any disclosures.