Purpose/Background
Obesity and low tumor location are well-recognized challenges in the surgical treatment of patients with rectal cancer. Additionally, the android male pelvis poses further complexity with resultant inferior outcomes compared to their female counterparts. We aimed to compare clinical and histopathological outcomes between obese males and females undergoing resection for low rectal cancer.

Methods/Interventions
We queried the ACS NSQIP database from 2016 to 2019. Adults older than 18 years with obesity and low rectal cancer undergoing radical resection were included. Obesity was defined as BMI > 30 kg/m2. Low rectal cancer was defined as tumor location at < 5 cm from the anal verge. Endpoints of interest included 30-day clinical outcomes and histopathological outcomes. Independent samples t-test and Chi-squared test were utilized to compare continuous and categorical variables, respectively. ANOVA test was used to compare continuous variables when the number of strata was more than 2.

Results/Outcomes: A total of 1,107 patients (433 females and 674 males) were included. The study groups were comparable in age, race, diabetes status, smoking status, functional status, ASA class, steroid use, cardiopulmonary disease, and clinical tumor staging. Operative time was significantly longer in males (349 vs. 329 min; p=0.016). Deep incisional surgical site infection (SSI) was more common in females (5.3% vs. 1.9%; p=0.002), whereas organ space SSI was more common in males (5.5% vs. 10.4%; p=0.013). No difference was found in the number of harvested lymph nodes (16.5 vs. 16.7; p=0.808) and circumferential resection margin (1.3 vs. 1.4 mm; p=0.663), whereas distal resection margin (DRM) was significantly longer in males compared to females (3.3 vs. 2.8 mm; p=0.010). When DRM was compared between different surgical approaches, the robotic approach was associated with the longest DRM (p=0.029). 

Conclusion
Space organ infection was nearly twice as common in obese males versus obese females with low rectal cancer. Nevertheless, obese males with low rectal cancer did not have worse histopathological features. Longer overall DRM in the robotic approach may be due to the higher rate of robotic surgery in males.