Abstract 6204: Age-related disparity in treatment outcome and adverse events among patients with metastatic colorectal cancer (mCRC)
Authors: Meng Lingbin , Thapa Ram , Xie Hao 
Published: June 2022

Abstract
Background: The number of newly diagnosed mCRC has been increasing in not only the aging population but also those &lt;50 years of age. However, age-related disparity in the management of patients with mCRC has not been adequately evaluated. In this study, we aimed to compare and contrast the treatment outcome and adverse events among different age groups of patients with mCRC.
Methods: We used individual patient data of a clinical trial (NCT00364013) from Project Data Sphere with patients who received first-line FOLFOX or FOLFOX + panitumumab for mCRC. Patients in each treatment arm were grouped into &lt;50 years, 50-65 years, and &gt;65 years of age groups. Continuous and categorical variables were compared with t test and Fisher’s exact test, respectively. Survival was summarized using Kaplan-Meier method and compared using log-rank test. Cox proportional hazards model was used to determine the association of adverse events with survival.
Results: Among 935 patients included, 112 (12.0%) were in the &lt;50 group; 456 (48.8%) were in the 50-65 group; 367 (39.2%) were in the &gt;65 group. All three groups had similar baseline characteristics. Median overall survival (OS) of both &lt;50 (18.4, 95%CI 13.1-23.1 months) and &gt;65 (18.0, 95%CI 16.3-22.2 months) groups were significantly shorter (p=0.008) than median OS of the 50-65 group (22.7, 95%CI 20.0-26.5 months) in the FOLFOX arm. Similar findings were present in the FOLFOX + panitumumab arm (p=0.049). Both &lt;50 and &gt;65 groups had a trend (p=0.09) toward shorter progression-free survival (PFS) compared to the 50-65 group. As to adverse events, in the FOLFOX arm, all grade nausea/vomiting of the &lt;50 group was more common than that in the &gt;50 group (70.3% vs 55.8%, p=0.05). Compared to the &gt;50 group, the &lt;50 group had earlier onset of neutropenia at 7.8 weeks (p=0.003) and chest pain at 5.4 weeks (p=0.008). In the FOLFOX + panitumumab arm, all grade fatigue (58.3% vs 35.7%, p=0.003), neuropathy (52.1% vs 34.7%, p=0.03) and mucositis (43.8% vs 29.5%, p=0.049) of the &lt;50 group were more common than those in the &gt;50 group. The duration of various adverse events were similar among the age groups. In the FOLFOX arm, severe (grade≥3) liver toxicity was associated with worse PFS (HR 3.6, 95%CI 1.3-9.8, p=0.01) and OS (HR 7.3, 95%CI 2.7-20.1, p&lt;0.001). In contrast, severe neuropathy was associated with better PFS (HR 0.6, 95%CI 0.4-0.9, p=0.009) and OS (HR 0.5, 95% 0.3-0.8, p=0.001). In the FOLFOX + panitumumab arm, severe anemia was associated with worse PFS (HR 1.7, 95%CI 1.02-2.8, p=0.04) and OS (HR 2.8, 95%CI 1.7-4.7, p&lt;0.001). In contrast, severe rash was associated with better PFS (HR 0.5, 95%CI 0.3-0.8, p=0.002) and OS (HR 0.3, 95% 0.2-0.5, p&lt;0.001).
Conclusions: Patients with early-onset mCRC had not only worse OS in both treatment arms but also higher incidence of adverse events. Our management approach should adapt to the unique features of this patient population.
Citation Format: Lingbin Meng, Ram Thapa, Hao Xie. Age-related disparity in treatment outcome and adverse events among patients with metastatic colorectal cancer (mCRC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6204.