Knepper, Todd C.

ImportanceWhile the incidence of early-onset metastatic colorectal cancer (mCRC) has been increasing, studies on the age-related disparity in this group of patients are limited.ObjectiveTo evaluate the association of age with treatment-related adverse events and survival in patients with mCRC and explore the potential underlying factors.Design, Setting, and ParticipantsThis cohort study included 1959 individuals. Individual data on 1223 patients with mCRC who received first-line fluorouracil and oxaliplatin therapy in 3 clinical trials, and clinical and genomic data of 736 patients with mCRC from Moffitt Cancer Center were used to assess genomic alterations and serve as an external validation cohort. All statistical analyses were conducted from October 1, 2021, through November 12, 2022.ExposuresMetastatic colorectal cancer.Main Outcomes and MeasuresSurvival outcomes and treatment-related adverse events were compared among patients in 3 age groups: younger than 50 (early onset), 50 to 65, and older than 65 years.ResultsIn the total population of 1959 individuals, 1145 (58.4%) were men. Among 1223 patients from previous clinical trials, 179 (14.6%) in the younger than 50 years group, 582 (47.6%) in the 50 to 65 years group, and 462 (37.8%) in the older than 65 years group had similar baseline characteristics except for sex and race. The younger than 50 years group had significantly shorter progression-free survival (PFS) (hazard ratio [HR], 1.46; 95% CI, 1.22-1.76; P < .001) and overall survival (OS) (HR, 1.48; 95% CI, 1.19-1.84; P < .001) compared with the 50 to 65 years group after adjustment for sex, race, and performance status. Significantly shorter OS in the younger than 50 years group was confirmed in the Moffitt cohort. The younger than 50 years group had a significantly higher incidence of nausea and vomiting (69.3% vs 57.6% [50-65 years] vs 60.4% [>65 years]; P = .02), severe abdominal pain (8.4% vs 3.4% vs 3.5%; P = .02), severe anemia (6.1% vs 1.0% vs 1.5%; P < .001), and severe rash (2.8% vs 1.2% vs 0.4% P = .047). The younger than 50 years group also had earlier onset of nausea and vomiting (1.0 vs 2.1 vs 2.6 weeks; P = .01), mucositis (3.6 vs 5.1 vs 5.7 weeks; P = .05), and neutropenia (8.0 vs 9.4 vs 8.4 weeks; P = .04), and shorter duration of mucositis (0.6 vs 0.9 vs 1.0 weeks; P = .006). In the younger than 50 years group, severe abdominal pain and severe liver toxic effects were associated with shorter survival. The Moffitt genomic data showed that the younger than 50 years group had a higher prevalence of CTNNB1 mutation (6.6% vs 3.1% vs 2.3%; P = .047), ERBB2 amplification (5.1% vs 0.6% vs 2.3%; P = .005), and CREBBP mutation (3.1% vs 0.9% vs 0.5%; P = .05), but lower prevalence of BRAF mutation (7.7% vs 8.5% vs 16.7%; P = .002).Conclusions and RelevanceIn this cohort study of 1959 patients, those with early-onset mCRC showed worse survival outcomes and unique adverse event patterns, which could be partially attributed to distinct genomic profiles. These findings may inform individualized management approaches in patients with early-onset mCRC.

663 Background: GI malignancies continue to be a major cause of cancer related deaths, despite advances in therapy options. In pancreatic cancer, the presence of homologous recombination mutations (HRM) has been shown to confer increased sensitivity to platinum chemotherapy. However, the role of HRM mutations in other GI cancers remains to be determined. The focus of this study is to evaluate the prognostic nature of core and noncore HRM in nonpancreatic GI cancers. Additionally, we aim to understand the predictive nature of these mutations related to platinum exposure. Methods: This was a retrospective review of patients at Moffitt Cancer Center with a primary stage IV nonpancreatic GI cancer treated with platinum therapy. All patients had next generation sequencing and were in the Clinical Genomics Action Committee database between 1/1/2013 and 11/1/2020. All patients had either a core HRM (BRCA1, BRCA2, PALB2) or noncore HRM (such as ATM, ATR, BARD1, BRIP1, FANCA, NBN, and RAD51). Patients were grouped into core HRM vs. noncore HRM. Response was stratified between responders (complete response and partial response) vs. non responders (stable disease and progressive disease), based on RECIST criteria. Progression free survival and overall survival were estimated using Kaplan-Meier method, and the log-rank test was used to assess the difference in progression free survival (PFS) and overall survival (OS) by HRM status and type of platinum therapy used. Results: There were 72 patients included in the study: the majority of patients were male (65.3%) and Caucasian (87.5%). Twenty-one (29.2%) patients had a core HRM and 51 (70.8%) had a noncore HRM. There was no significant difference in response rate between patients with core HRM and patients with noncore HRM for evaluable patients (n = 66): 20.0% of patients with core HRM vs. 21.7% of patients with noncore HRM demonstrated a response to platinum therapy (p = 0.41). An improved OS was noted for patients with core HRM vs. those with noncore HRM at 68.9 vs. 24.3 months (p = 0.019). An improved PFS was also seen in patients with core HRM at 10.4 months vs. 6.3 months with noncore HRM (p = 0.027). There was no difference in PFS based on type of platinum therapy used (oxaliplatin vs. carboplatin vs. cisplatin), while an improved OS was noted for patients treated with oxaliplatin vs. carboplatin vs. cisplatin at 43.1 vs. 28.2 vs. 16.0 months (p = 0.011). Conclusions: Our study demonstrated that in stage IV nonpancreatic GI malignancies treated with platinum therapy, patients with core HRM had a greater OS and PFS compared to those with noncore HRM, suggesting a potential prognostic and predictive role of these mutations. Further studies are needed to confirm our findings.