The IDEA study has influenced the prescribing of adjuvant therapy for patients with stage III colon cancer, according to research published in the Journal of the National Comprehensive Cancer Network.¹

Researchers conducted a real-world analysis of prescribing patterns for adjuvant therapy in patients with stage III colon cancer to determine if results from the IDEA study influenced practice.

IDEA was a pooled analysis of 6 randomized, phase 3 trials.² It was conducted to determine if the duration of adjuvant therapy in stage III colon cancer could be reduced from 6 months to 3 months. Adjuvant therapy consisted of fluorouracil plus leucovorin and oxaliplatin (FOLFOX) or capecitabine plus oxaliplatin (CAPOX).

The 3-month treatment duration did not meet criteria for noninferiority to the 6-month treatment duration in the overall cohort (hazard ratio [HR], 1.07; 95% CI, 1.00-1.15).

When the researchers looked at results by treatment type, they found that 3 months of treatment was noninferior to 6 months in patients who received CAPOX (HR, 0.95; 95% CI, 0.85-1.06) but not in those who received FOLFOX (HR, 1.16; 95% CI, 1.06-1.26).

In the current analysis, the researchers evaluated whether these results altered adjuvant chemotherapy prescribing patterns in patients with stage III colon cancer from January 1, 2016, to January 31, 2021.¹

The analysis included 399 patients. Most patients (68.4%) had a planned 6-month duration of treatment, but 31.6% had a planned 3-month duration of treatment.

There was a significant increase in the use of 3-month adjuvant chemotherapy from before the IDEA abstract was presented in June 2017 to after the full manuscript of IDEA was published in March 2018. Accordingly, the use of 6-month treatment decreased over that time period.

The use of 3-month treatment increased from 5.6% before the abstract was presented to 45.2% after the full manuscript was published (P <.001). The use of 6-month treatment decreased from 94.4% to 54.8% (P <.001).

The use of adjuvant FOLFOX decreased overall, from 86.0% before the abstract presentation to 52.0% after the full manuscript publication (P <.001). There was an increase in the use of FOLFOX for 3 months (3.7% to 10.0%; P <.001) and a decrease in the use of FOLFOX for 6 months (82.2% to 42.1%; P <.001).

The use of adjuvant CAPOX increased overall, from 14.0% before the abstract presentation to 48.0% after the full manuscript publication (P <.001). There was an increase in the use of CAPOX for 3 months (1.9% to 35.3%; P <.001) and an increase in the use of CAPOX for 6 months (12.1% to 12.7%; P <.001).

“Despite the IDEA collaboration failing to demonstrate noninferiority of 3 months’ duration of adjuvant therapy compared with 6 months, the findings have influenced practice prescribing patterns, favoring CAPOX and a shorter duration of planned adjuvant treatment,” the researchers summarized.

The team also found that the transition toward 3 months of chemotherapy was adopted earlier in Black patients than in White patients, as was the adoption of 3 months of CAPOX.

“One consideration may be racial and ethnic differences in the incidence of capecitabine-related toxicities; however, the findings are limited [due] to the small number of Black patients in our study,” the researchers wrote. “Our planned follow-up study will evaluate clinical outcomes in resected stage III colon cancer with adjuvant chemotherapy, including clinical outcomes associated with oxaliplatin discontinuation in a US-based patient population.”

Disclosures: One study author declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.

References

1. Ou F-S, Walden DJ, Larson JJ, et al. Changes in prescribing patterns in stage III colon cancer. J Natl Compre Canc Netw. Published online August 7, 2023. doi:10.6004/jnccn.2023.7028

2. Grothey A, Sobrero AF, Shields AF, et al. Duration of adjuvant chemotherapy for stage III colon cancer. N Engl J Med. 2018;378(13):1177-1188. doi:10.1056/NEJMoa1713709