EP505 - Surgical Treatment among Newly Diagnosed Colorectal Cancer in Southwest China: A Population-Based Study

Purpose/Background: Whether surgical treatment constitutes the principal intervention for colorectal cancer (CRC) patients remains poorly evidence in real-world settings, especially in developing countries. A large-scale, population-level analysis is therefore essential to delineate the pivotal role of surgery. This study aimed to analyze the surgical treatment characteristics for newly diagnosed CRC patients based on a regional database in Southwest China.

Methods/Interventions: We collected data from all patients aged ≥18 years diagnosed with primary CRC from Jan 1, 2020, to Dec 31, 2023, in Sichuan province, China, from a regional database of longitudinal clinical data for inpatients. We estimated the proportion of patients receiving surgery (primary lesion resection and neostomy ) within the first year after diagnosis by sex, age, tumor site, and organ metastasis at diagnosis, and classified the timing of neostomy into four mutually exclusive subgroups: neostomy only, before, synchronized，and after primary tumor resection. We analyzed the timing of neostomy and compared their differences in subgroups and calculated the length of time from neostomy to stoma reversal procedure.

Results/Outcomes: A total of 118,787 newly diagnosed CRC patients were identified, with a mean age of 66.4±12.3 years at diagnosis, 59.6% males, 54.4% rectal cancer cases, and 13.8% cases exhibiting synchronous organ metastasis at diagnosis. Over the four-year period of 2020-2023, the mean age at diagnosis rose by 0.4 years, the proportion of elderly patients (aged ≥70 years) increased by 2.1%, and the cases presenting with synchronous organ metastasis grew by 1.4%. During the first year after diagnosis, 71.2% (95%CI: 71.0%-71.5%) patients underwent primary lesion resection and 22.3% (95%CI: 22.1%-22.6%) received neostomy, both demonstrating significantly increasing annual trends (χ2trend=72.2, P< 0.001; χ2trend=70.6, P< 0.001) while showing inverse correlations with advancing age (χ2trend=4 096.0,P < 0.001; χ2trend=56.3, P< 0.001). Subgroup analyses revealed significantly lower primary lesion resection rates among females vs. males, rectal cancer vs. colon cancer, and organ metastasis vs. non-organ metastasis patients (P < 0.001), whereas neostomy rates were higher in females and rectal cancer patients but lower in organ metastasis cases (P < 0.001). Among patients received neostomy within the first year after diagnosis, 13.4% had neostomy only, 2.3% received neostomy before primary tumor resection, 78.9% had synchronous neostomy with primary tumor resection, and the resting 5.5% had neostomy after primary tumor resection. Among patients underwent stoma creation within the first year after diagnosis, 42.6% (95%CI:42.0%-43.2%) subsequently underwent stoma reversal, with a median interval of 123 (interquartile range: 95, 188) days, 72.5% reversals within 6 months, 23.9% during 6-12 months, and 3.6% after 12months. Proportion of stoma reversal presented an increasing trend with diagnosis year (χ2trend=80.0, P< 0.001) but decreased with advancing age at diagnosis (χ2trend=1,072.4, P< 0.001).

Conclusion/Discussion: In southwestern China, newly identified CRC cases and the proportions of patients undergoing primary tumor resection, neostomy and stoma reversal presented an increasing trend.

Primary Tumor Resection, Stoma Creation, and Reversal Within 1 Year of Diagnosis Among Newly Diagnosed Colorectal Cancer Patients by Characteristics [%（(Number of Stoma Procedures / Number of Cases with Different Characteristics in the Same Year)]