A significant and increasing trend towards the use of a three-month rather than six-month adjuvant chemotherapy regime in stage 3 colon cancer has been observed following publications from the IDEA collaboration abstract.
The use of a six-month regimen of FOLFOX (fluorouracil, leucovorin, and oxaliplatin) or CAPOX (capecitabine and oxaliplatin) became the standard adjuvant therapy in stage 3 disease from 2004 when trials convincingly showed that the addition of oxaliplatin improved overall survival. But whether treatments regimens could be shorter while maintaining efficacy remained uncertain.
In 2018, the International Duration Evaluation of Adjuvant Therapy (IDEA) collaboration prospectively pooled data from six randomised clinical trials of adjuvant therapy involving 12,000 patients with stage 3 colon cancer. The aim of the analysis to evaluate whether a shorter, three months regimen of either FOLFOX or CAPOX was non-inferior to six months worth of treatment, in terms of the rate of disease-free survival at three years.
It was identified that a three month FOLFOX regime was not non-inferior to six months. In contrast, non-inferiority was seen for patients treated with CAPOX, particularly in the lower-risk subgroup.
In the most analysis published in the Journal of the National Comprehensive Cancer Network, researchers set out to evaluate the impact of these results from the IDEA collaboration on adjuvant chemotherapy prescribing practice patterns, including the planned adjuvant treatment regimen and duration.
Three-month chemotherapy regimes
A total of 399 patients with stage 3 colon cancer who received adjuvant chemotherapy were included in the analysis. There was a significant increasing trend for the use of three months of adjuvant chemotherapy following publication of the IDEA abstract ( p <0.001). In addition, CAPOX prescribing also significantly increased from 14% to 48% (p <0.001). In fact, adoption of three months of CAPOX was similar in patients with low- and high-risk cancer.
Commenting on their findings, senior study author Daniel Ahn, oncologist at the Mayo Clinic Comprehensive Cancer Center, said: ‘Our study results showed a significant increase in planning for three months of adjuvant chemotherapy after the presentation of IDEA. We also observed that more patients were prescribed CAPOX compared to FOLFOX, which had previously been more widely used as the preferred treatment regimen of choice.‘
He added: ‘The biggest concern with six months of chemotherapy are the toxicities from treatment –including low blood counts, kidney and liver dysfunction, and peripheral neuropathy (intolerable numbness and/or weakness). Patients that receive six months of adjuvant chemotherapy are greater than five times more likely to experience grade III or higher peripheral neuropathy.
‘Of course, with three months of chemotherapy we have to be concerned about whether the shortened duration can potentially negatively affect cancer outcomes. Given these nuances, the choice of regimen and duration remains a shared decision.‘
Globally, colon cancer is the third most common cancer. It leads to a considerable number of deaths but is preventable if caught at an early stage. Delays in diagnosis witnessed during the Covid-19 pandemic have already been shown to result in a higher number of advances cases being subsequently detected.
