307 - Patient Reported Quality of Life and Functional Outcomes after Pre-Operative Short- vs. Long-Course Radiotherapy for Rectal Adenocarcinoma

S. N. Shah¹, K. M. Frechette², W. S. Harmsen³, R. Roden⁴, M. G. Haddock¹, K. W. Merrell¹, C. M. Callaghan⁵, J. B. Ashman⁶, H. Xie⁷, K. L. Mathis⁸, S. Shawki⁵, E. J. Dozois⁸, Z. Jin⁷, W. Perry⁵, C. L. Hallemeier¹, and K. R. Jethwa¹; ¹Department of Radiation Oncology, Mayo Clinic, Rochester, MN, ²Mayo Clinic Department of Radiation Oncology, Rochester, MN, ³Department of Biostatistics and Health Sciences Research, Mayo Clinic, Rochester, MN, ⁴Mayo Clinic Alix School of Medicine, Rochester, MN, ⁵Mayo Clinic, Rochester, MN, ⁶Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ, ⁷Division of Medical Oncology, Mayo Clinic, Rochester, MN, ⁸Division of Colon & Rectal Surgery, Mayo Clinic, Rochester, MN

Purpose/Objective(s): Preoperative short-course radiotherapy (SCRT) and long-course chemoradiotherapy (LCCRT) are standard options for patients with rectal adenocarcinoma, however, patient-reported outcomes (PROs) after radiotherapy (RT) have not been well studied. Our objective was to compare PROs for patients treated with SCRT vs. LCCRT. Materials/

Methods: This was an IRB-approved retrospective cohort study that included patients with rectal adenocarcinoma treated with pre-operative SCRT or LCCRT from 2013-2024 with available PROs. PROs were prospectively collected at baseline prior to RT, 3-months and 1-2 years after RT utilizing the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Colorectal Cancer Module 29 (EORTC QLQ CR29). The analysis focused on the overall score, and secondarily on bowel, urinary, and sexual scales. The defecation or stoma problems scale incorporates flatulence, fecal incontinence or leakage, sore skin around anus or stoma, stool frequency, or embarrassment by defecation patterns or stoma. Comparisons of the median change from baseline at each timepoint between SCRT vs. LCCRT were made using the Wilcoxon rank sum test.
Results: 220 patients were included for analysis. 126 (57%) received LCCRT and 94 (43%) received SCRT. Patient characteristics included mean age of 57 years (range 24-90), male sex (60%), and ECOG 0-1 (99%). LCCRT was associated with a greater proportion of stage III disease (75% vs. 51%), cT4 (29% vs. 11%), cN2 (46% vs. 12%), compromised mesorectal fascia (24% vs. 15%), lateral pelvic lymphadenopathy (33% vs. 7%) and tumors < 5 cm from the anal verge (53% vs. 38%) compared with SCRT. Most common RT regimens were 50-50.4 Gy in 25-28 fractions (95%) and 25 Gy in 5 fractions (96%) for the LCCRT and SCRT groups. Chemotherapy was delivered preoperatively (46% vs. 34%) for the LCCRT vs. SCRT groups. The median time from RT to surgery was 56 days (IQR 48-70) and 3 days (IQR 1-4) for the LCCRT and SCRT groups. Surgical technique included low anterior resection (65% vs. 75%) or abdominoperineal resection (35% vs. 26%) for the LCCRT and SCRT groups. PROs are demonstrated in the table. No significant differences in change from baseline between treatment cohorts in overall score, defecation or stoma problems, blood and mucus in stool, urinary, or sexual scales at any timepoint.
Conclusion: These data suggest comparable impact on PROs for both SCRT and LCCRT and further support each approach as an appropriate treatment strategy for patients with rectal cancer. Abstract 307 – Table 1

Scale	Baseline (n=220)		3-months (n=102)		1-2 years (n=113)
	LCCRT	SCRT	LCCRT	SCRT	LCCRT	SCRT
Overall	18.9	18.9	1.7	4.4	0.9	-2.5
Defecation and stoma problems	11	11	5.5	11	11	5.5
Blood and mucus in stool	16.5	16.5	-16.5	-16.5	-16.5	-16.5
Urinary frequency	33	33	0	0	0	0
Dysuria	0	0	0	0	0	0
Dyspareunia (women)	0	0	0	0	0	0
Impotence (men)	33	33	0	0	0	0
Reported as baseline absolute score and median change from baseline at follow-up Higher score indicates worse symptoms or function *p<0.05