Tumor sidedness and the usefulness of laparoscopic surgery in obese colorectal cancer patients in Japan

Numerous reports suggest that there is no difference in treatment outcomes between obese and non-obese patients undergoing laparoscopic surgery for colorectal cancer. However, contrasting findings also suggest that treatment results may be inferior in obese patients. We aimed to retrospectively analyze outcomes of laparoscopic and open surgeries for right- and left-sided colectomies in 1572 obese patients with colorectal cancer. Patients were classified by surgical type (laparoscopic vs. open) and colectomy location (right vs. left). We assessed body mass index, tumor diameter, blood loss, operative time, lymph nodes removed, metastases, recurrence rate, and overall survival. No relationship was found between body mass index and the surgical method. Tumor diameter was significantly larger in open surgeries for both sides (p < 0.001). The combined resection rate was also significantly higher in open surgeries (p < 0.001). Laparoscopic surgeries resulted in significantly lower blood loss but significantly longer operative times on both sides (p < 0.001). No difference in operative times was noted between left and right laparoscopic surgeries, whereas left-sided open colectomies took significantly longer (p = 0.9086, p < 0.001). Lymph node-positive metastasis rate, recurrence rate, and overall survival showed no differences. Combined resection (T4b) and tumor size are more critical than body mass index in selecting the surgical approach. Open surgeries had longer operative times for left-sided colectomies, whereas laparoscopic surgeries showed no time difference between sides, suggesting potential advantages for left-sided procedures or greater difficulty with right-sided colectomies. Despite longer operative times, laparoscopic surgery's lower blood loss indicates its oncological safety.