Transverse colon primary analysis for CO20 and CO17 Wednesday, February 08, 2023 Congratulations to Dr. Vasconcelos, a BC Cancer GI Medical Oncology Fellow, was selected by the CCTG review committee to be awarded the The Frances A Shepherd Award for his abstract: Transverse colon primary analysis for CO20 and CO17 which was selected for the ASCO Gastrointestinal Cancers Symposium. The January 21, 2023 poster presentation was recognized with a symposium merit award - awarded to fellows/oncology trainees whose research is addressed in high-quality abstracts submitted to the meeting and recognized for its scientific merit. “I am deeply honored to have been selected for the prestigious Frances A. Shepherd Award. This is a huge incentive for a trainee to carry on with research. As with any scientific project this was a group effort and could not have been done without the valuable help from my supervisor Dr. Jonathan Loree and the co-authors. Our abstract was built upon exceptional work done by the investigators involved in the CO17 and CO20 trials. Those pivotal trials are still providing answers to important questions years after their completion. That shows the importance of well-designed and conducted clinical trials and CCTG leadership in the field," says Dr. Vasconcelos. The Frances Shepherd Award is given to investigators or post-graduate trainees, traveling to present CCTG related work at major international meetings where the material has been accepted for presentation. There is still an opportunity to apply until June 2023. About the abstract In this abstract, researchers examined the predictive and prognostic characteristics of transverse colon as a primary tumor location in a cohort of patients with metastatic colorectal cancer (mCRC) from the Canadian Cancer Trials Group {CCTG) CO.17 and CO.20 trials. The results showed that transverse colon mCRC has comparable predictive and prognostic features to right sided mCRC. Additionally, we found that left-sided primary tumors had a better overall prognosis and response to treatment with Cetuximab in this cohort of heavily pre-treated patients. The findings provide important information as it clarifies that the optimal division for sidedness should be after the transverse colon. It moves the field forward since previous data on mCRC arising from the transverse colon was limited due its exclusion from many landmark analysis. Furthermore, the study expands the knowledge of reduced efficacy of Cetuximab in non-left sided metastatic mCRC from first line setting to latter line. Finally, the results may be useful for informing the development of future clinical trials and treatment guidelines for mCRC as well as help clinicians to make better treatment recommendations, potentially leading to improvement in patients outcomes. Results: 553 patients were included, 201 (36.3%) from CO.17 and 352 (63.7%) from CO.20. Primary site distribution was: 32 (5.8%) transverse, 101 (18.3%) right and 420 (75.9%) left. On multivariate analysis from 457 (82.6%) patients treated with Cet, left side was associated with superior OS (HR, 0.40; 95% CI, 0.24-0.68,p = 0.0006) and PFS (HR, 0.48; 95% CI,0.29-0.79, p = 0.004) compared to transverse colon. No significant difference was noted in OS (HR, 0.74; 95% CI, 0.41-1.31, p = 0.30) and PFS (HR, 0.79; 95% CI, 0.46-1.36, p = 0.40) between right side versus transverse colon. Sidedness was not associated with prognostic difference in OS or PFS in the 96 (17.4%) patients receiving BSC alone. Outcomes according to primary site and treatment are shown in table 1. Conclusions: Transverse mCRC has comparable prognostic and predictive features to right sided mCRC. In keeping with previous studies, left side was predictive of greater Cet benefit and presented better overall prognosis when single agent Cet was used after 5-FU, oxaliplatin and irinotecan.
