Biomedical subjects

Kozo Kataoka

Publications and source records attributed to Kozo Kataoka.

2 recordsLinked to original sources

PubMed2026

Laparoscopic Surgery Is Associated With Reduced Small Bowel Obstruction Risk After Colorectal Cancer Surgery: A Nationwide Cohort Study of 5458 Patients.

INTRODUCTION: Postoperative small bowel obstruction (SBO) is a major complication following colorectal cancer surgery, yet evidence-based prevention strategies remain unclear. We aimed to clarify site-specific risk factors for SBO and evaluate the effectiveness of laparoscopic surgery and adhesion prevention materials (APMs) in preventing SBO after colorectal cancer surgery. METHODS: This retrospective cohort study analyzed 5458 patients who underwent colorectal cancer surgery at 32 Japanese institutions between 2012 and 2014. The primary endpoint was the 5-year risk of SBO. We evaluated the effects of laparoscopic surgery, APM use, and stoma creation on SBO risk. Clinical variables included demographics, tumor site, operative approach, operative details, and postoperative complications. Hospital-level clustering was addressed using mixed-effects logistic regression. RESULTS: Overall SBO incidence was 5.2% (n = 283). Rectal cancer had the highest risk, whereas all colonic sites except the descending colon showed significantly lower odds. Laparoscopic surgery was associated with a 42% reduction in odds (OR 0.58; 95% CI 0.45-0.74; p < 0.001), with significant reductions in ascending (NNT = 22.2, p = 0.001) and sigmoid colon surgery (NNT = 30.2, p = 0.003). APMs showed no protective effect (OR 1.01; 95% CI 0.78-1.32; p = 0.94). Stoma creation significantly increased SBO risk (OR 1.84; 95% CI 1.35-2.51; p < 0.001). Secondary analysis identified reoperation and postoperative ileus as additional independent risk factors. DISCUSSION: Laparoscopic surgery was associated with reduced long-term SBO risk, with significant benefits in ascending and sigmoid colon surgery. APMs showed no measurable benefit. Stoma creation increased SBO risk, with no observed difference between ileostomy and colostomy.

adhesion prevention material↗

PubMed2025

Molecular Residual Disease and Recurrence in Rectal Cancer Patients Undergoing Upfront Surgery: A Prospective Cohort Study.

OBJECTIVE: To evaluate the prognostic utility of postoperative circulating tumor DNA (ctDNA) for recurrence and treatment response in patients with rectal cancer undergoing upfront surgery. BACKGROUND: ctDNA-based molecular residual disease (MRD) testing shows promise in colorectal cancer, but its role in patients with rectal cancer not receiving neoadjuvant therapy is unclear. This study evaluates whether postoperative ctDNA predicts disease-free survival (DFS) and guides adjuvant chemotherapy (ACT) decisions. METHODS: We analyzed ctDNA from patients with stage II to III rectal cancer (N=250) enrolled in the GALAXY study, a multicenter registry in Japan. A clinically validated, personalized, tumor-informed 16-plex PCR next-generation sequencing assay (Signatera) was used to detect and quantify ctDNA. The primary outcome was DFS, defined as the time from landmark to recurrence, death, or the latest radiologic assessment. RESULTS: In the MRD window (2-10 wk postsurgery, before ACT), 14.2% (35/246) of patients were ctDNA-positive and had significantly shorter DFS (HR: 9.96, 95% CI: 5.76-17.2, P <0.0001). Among patients who were ctDNA-positive in the MRD window, a significant benefit from ACT was observed (HR: 0.28, 95% CI: 0.09-0.89, P =0.031), whereas no benefit was seen in ctDNA-negative patients (HR: 0.59, 95% CI: 0.26-1.35, P =0.211). When analyzing ctDNA dynamics from the MRD window to 6 months postsurgery, recurrence risk was higher in patients who converted from ctDNA-negative to positive (HR: 8.22, 95% CI: 1.86-36.32, P =0.0055) and who remained ctDNA-positive (HR: 45.48, 95% CI: 14.31-144.57, P <0.0001) compared with serially ctDNA-negative patients. CONCLUSIONS: Postoperative ctDNA status is a robust biomarker predicting recurrence risk and ACT benefit in patients with rectal cancer undergoing upfront surgery.

Humans↗