2296 - Impact of Diagnostic and Treatment Delays on Survival in Locally Advanced Rectal Cancer Treated with Neoadjuvant Chemoradiotherapy: A Multi-Center Cohort Study

03:00pm - 04:00pm ET

Poster Hall - Exhibit Hall A

Screen: 20

POSTER

Presenter(s)

Jiahao Zhu, MD - Suzhou Hospital affiliated to Nanjing Medical University, Wuxi, Jiangsu

J. Zhu¹, Y. Zhao¹, B. Xu², K. Gu¹, S. Ji³, B. Yang¹, and L. Zhou¹; ¹Affiliated Hospital of Jiangnan University, Wuxi, Jiangsu, China, ²Department of Outpatient Chemotherapy, Harbin Medical University Cancer Hospital, Harbin, Heilongjiang, China, ³Department of Radiotherapy and Oncology, the Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, Jiangsu, China

Purpose/Objective(s):

Timely diagnosis and treatment are essential for quality cancer care, yet prior colorectal cancer studies report inconsistent associations between clinical delay and survival, partly due to heterogeneous staging and treatment strategies. We evaluated the impact of diagnostic and treatment delays on survival in patients with locally advanced rectal cancer (LARC) uniformly treated with neoadjuvant chemoradiotherapy (NCRT) followed by surgery.

Materials/Methods:

This retrospective study included 450 Chinese patients from three tertiary centers and 5,810 American patients from the SEER database (2010–2019), all with stage II–III rectal adenocarcinoma treated with NCRT followed by surgery. Diagnostic delay was defined as the interval from symptom onset to histopathologic diagnosis (Chinese cohort only). Treatment delay was defined as the interval from diagnosis to NCRT initiation. A 5-month cutoff for diagnostic delay was determined using X-tile. Treatment delay was categorized as =1 month, >1–2 months, and >2 months. Primary endpoints were overall survival (OS), cancer-specific survival (CSS), and disease-free survival (DFS). Kaplan–Meier and multivariable Cox regression analyses were performed.

Results:

In the Chinese cohort, median diagnostic delay was 5 months (IQR 3–6) and median treatment delay was 8 days (IQR 5–13). In the American cohort, median treatment delay was 1 month (IQR 1–2), and 6.8% experienced delays >2 months. Diagnostic delay >5 months was independently associated with worse OS (HR 1.50, 95% CI 1.02–2.21, P=0.041) and DFS (HR 1.36, 95% CI 1.01–1.85, P=0.047) in the Chinese cohort. No association was observed with CSS or pathologic complete response. In the American cohort, treatment delay >2 months independently predicted inferior OS (HR 1.52, 95% CI 1.20–1.92, P<0.001) and CSS (HR 1.58, 95% CI 1.20–2.09, P=0.001), whereas delays of >1–2 months were not significantly different from =1 month. Age remained an independent prognostic factor in both cohorts.

Conclusion:

In LARC patients receiving standard NCRT followed by surgery, diagnostic delay >5 months and treatment delay >2 months were significantly associated with poorer survival. These findings support =5 months from symptom onset to diagnosis and =2 months from diagnosis to treatment as clinically meaningful timeliness benchmarks and potential quality-of-care indicators in rectal cancer management.