Parish, Marie

656 Background: Non-neutropenic enterocolitis (NNEC), a potentially fatal toxicity of capecitabine (CAPE), is under-reported in the literature. An institutional review was performed to determine the incidence, clinical course, and outcome of patients developing CAPE-induced NNEC. Methods: After the institutional review board approval, a database search identified patients requiring inpatient care for CAPE-induced diarrhea over a period of 6 years (between 01/2015 and 12/2020). Among the patients requiring hospital admission, patients with radiologic features of enterocolitis were included in the analysis. Data on patient characteristics, imaging study results, clinical course, and outcomes were gathered by electronic chart review. Results: Among the 789 patients treated with CAPE, 25 patients (3%) developed grade 3 or higher diarrhea requiring hospital admission, and 13 out of these 25 patients (1.6 % of patients treated with CAPE) had evidence of enterocolitis on CT scan: ileitis in 7/13 (54%), colitis in 1/13 (8%), and both in 5/13 (38%) patients. The median age of the patient cohort was 64 years (range, 31-81), 8/13 (62%) were female, and all patients were Caucasian. CAPE was administered for the following indications: breast cancer in 6 patients, colorectal cancer in 4 patients, cholangiocarcinoma in 2 patients, and neuroendocrine tumor in 1 patient. ECOG performance status at the time of CAPE initiation was 0 in 7 patients and 1 in 6 patients. Most patients (7/13, 54%) received single-agent CAPE, and the majority (10/13, 77%) developed diarrhea with the first cycle after a median of 21 days (range, 10-50). Patients were hospitalized after a median of 27 days (range, 13-51), and the median hospital stay was 12 days (range, 4-25). None of the 13 patients demonstrated neutropenia at the time of hospital admission. The associated adverse effects at the time of admission included grade 3 abdominal pain in 8 (62%) patients, grade 3 nausea in 7 (54%) patients, and grade 3 vomiting in 3 (23%) patients. Hypokalemia and oral mucositis were present at admission in 6 (46%) and 2 (15%) patients, respectively. Stool studies performed in 11 (85%) patients ruled out infection. Testing for dihydropyrimidine dehydrogenase deficiency performed in 4 (31%) patients was negative. All patients were treated with supportive measures, and 2 (15%) patients required total parenteral nutrition. All but 1 patient recovered fully; 1 patient died due to a condition unrelated to CAPE. Intravenous infusional 5-fluorouracil (5-FU) administration in 3 patients after the recovery was tolerated well. Conclusions: CAPE-induced NNEC is uncommon and generally occurs after the first cycle of therapy. Most patients developing CAPE-induced NNEC recover fully with appropriate supportive measures. Infusional 5-FU-based regimens appear to be safe in this patient group.

44 Background: Despite an alarming rise in incidence, data on survival outcome and treatment response of young-onset (age < 50 years) locally advanced rectal cancer (YO-LARC) patients receiving total neoadjuvant therapy (TNT) are sparse. We retrospectively compared the outcome between YO-LARC and later-onset (aged 50 years or older) LARC (LO-LARC) patients treated with TNT. Methods: After the institutional review board approval, electronic medical records of the LARC (T3/T4 or node-positive) patients treated with TNT at a tertiary care cancer center between January 1, 2015, and June 30, 2020, were reviewed for data collection. TNT consisted of systemic chemotherapy with oxaliplatin-based regimens for 16 weeks followed by long-course radiation with concurrent capecitabine or 5-fluorouracil (CRT). Patients receiving only preoperative CRT were excluded. Most patients underwent surgical resection following the TNT. Non-operative management was offered to patients if TNT resulted in clinical complete response (cCR). The following comparisons between the YO-LARC and the LO-LARC patients were performed: patient characteristics, pathological complete response (pCR) rate, combined pCR + cCR rate, disease-free survival (DFS), and overall survival (OS). Results: Of 72 patients included in the analysis, 44(61%) were male, 49 (68%) were Caucasian, and 62 (86%) had clinical stage III disease. The study included 26 (36%) patients with YO-LARC (median age, 43 years) and 46 (64%) patients with LO-LARC (median age, 64 years). The comparison of patient characteristics that included gender, clinical stage, baseline carcinoembryonic antigen level, the distance of the tumor from the anal verge, presence of high-risk features, and histologic grade did not differ significantly between the groups. There were no statistically significant differences in pCR and combined pCR+cCR rates (p = 0.16) between the groups: YO-LARC, 12 % (3/26) and 15 % (4/26), respectively; LO-LARC, 22% (10/46) and 30% (14/46), respectively. Either group did not reach median DFS and OS after a median follow-up of 38 months for survivors. The estimated 5-year OS rates in patients with YO-LARC and LO-LARC were 86 % (95% confidence interval [CI], 69% to 100%) and 84% (95% CI, 68% to 100%), respectively (p = 0.92). The estimated 3-year DFS rates in patients with YO-LARC and LO-LARC were 67 % (95% CI, 50% to 89%) and 83% (95% CI, 72% to 95%), respectively (p = 0.19). Conclusions: The current retrospective analysis did not demonstrate significant differences in the pCR rates, combined pCR +cCR rates, DFS, or OS between the YO-LARC and LO-LARC patients treated with TNT.