Outcomes in management of locally advanced rectal cancer with total neoadjuvant therapy in an underserved population.

Abstract

208 Background: The use of total neoadjuvant therapy is now standard of care and is favored when treating locally advanced rectal cancer but its treatment is seldom studied in an underserved population. Methods: A retrospective study was conducted on patients with Stage II and III locally advanced colorectal cancer treated with either total neoadjuvant therapy (TNT) followed by resection or conventional therapy (CT) with chemoradiation followed by surgery, with or without adjuvant treatment afterwards. Patients completed treatment between 2015 and 2023 at the Hartford Hospital Helen and Harry Gray Cancer Center at Hartford, Connecticut. Data collected included demographics, type of treatment, tumor location (high vs mid vs low) and pathological response to treatment spread out among the two groups. Propensity score matching was used to minimize baseline differences between the two groups, adjusted for age, gender, ethnicity and tumor location and Fisher’s exact test was performed to then check for significance. Results: Out of the 133 patients analyzed, 90 underwent TNT, and 43 received CT. The average age at diagnosis was 57.5 years (SD: 11.15). In the TNT group, 79 patients (87.7%) achieved either a partial or complete response (PCR), while 11 patients (12.3%) had No response (NR). Tumor locations in the TNT group were distributed as follows: 13.4% (n=12) had high tumors, 34.4% (n=31) had mid tumors, and 52.2% (n=47) had low tumors. In the CT group, 31 patients (72.9%) achieved PCR, while 12 patients (27.9%) had NR. Tumor locations in the CT group were distributed as follows: 9.3% (n=4) had high tumors, 51.2% (n=22) had mid tumors, and 39.5% (n=17) had low tumors. After propensity score matching and adjusting for demographic covariates, the TNT group demonstrated a higher proportion of responders compared to the CT group (p=0.048). Furthermore, 40% (n=36) of patients in the TNT group achieved a complete response, compared to 32% (n=14) in the CT group. Partial response rates were 39.5% (n=17) in the TNT group and 47.8% (n=43) in the CT group. Conclusions: TNT demonstrated superior pathological response rates compared to CT, which supports its growing role in the management of locally advanced rectal cancer even in this underserved population.