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Purpose: The impact of obesity per se on the surgical strategy i.e. sphincter sacrifice (abdominoperineal resection, APR) vs. restorative rectal resection (RRR), perioperative outcomes, and long-term maintenance of intestinal continuity has been poorly studied in patients with mid and low rectal cancer. We compare these outcomes for obese and non-obese patients with mid and low rectal cancer undergoing surgery.
Methods: All patients undergoing curative surgery for mid or low rectal adenocarcinoma at a single institution from 1976-2011 were identified from a prospective cancer database. Obese and non-obese patients were matched 1:2 for age, gender, ASA class, location (low or mid rectum) and stage of tumor. Demographics, use of neoadjuvant chemoradiothrapy (NCRT) and adjuvant therapy, operative and perioperative outcomes, pathology, longterm outcomes including oncologic outcomes and whether or not restoration of intestinal continuity was performed were compared.
Results: 157 obese patients and 314 non-obese patients, mean age 62 years at proctectomy were included. The groups were similar for matched characteristics. NCRT rate was higher in obese patients (p=0.048). A similar proportion of non-obese and obese patients underwent RRR (p=1) while postoperative hospital stay (p=0.23) and 30-day postoperative reoperation (p=0.83), mortality (p=1) and readmissions (p=0. 13) was similar. Non-obese and obese patients also had similar tumor differentiation (p=0.92) and lymph nodes examined (p=0.64). Anastomotic leak was greater in obese patients (p=0.0003). End colostomy could not been reversed in 8 cases (3 obese and 5 non-obese, p=1) after a Hartmann’s procedure which was performed as the initial curative intervention. During follow up, a loop ileostomy was created after an ileal pouch anal anastomosis, because of pouch failure and two cases (1 obese and 1 nonobese, p=1) received a permanent stoma after secondary operations for recurrences. Cancer specific mortality (p=0.55) and local recurrence (p=0.56) were similar for non-obese and obese patients after similar mean follow up time of 5 years for both groups (p=0.4).
Conclusion: At a high-volume specialized colorectal unit, proctectomy can be performed with similar longterm oncologic outcomes and ability to restore intestinal continuity in obese patients when compared with the non-obese. The increased technical complexity expected in obese patients likely explains the associated increased use of NCRT and occurrence of anastomotic leak in obese when compared with non-obese patients.

Characteristics of the groups

	Non obese (n=314)	Obese (n=157)	P value
Age	62.2±10.2	61.6±10.7	0.62
Gender (male)	230	115	1
ASA score ‡	3 (1-4)	3 (1-4)	1
Body mass index (kg/m2)	24.9±3.6	35.7±4.6	<.0001
Tumor location (low/mid rectum)	120/194	60/97	1
Neoadjuvant chemoradiation	121 (38.5 %)	76 (48.4 %)	0.048
Restorative rectal resection	241 (76.8%)	121 (77.1 %)	1
Postoperative hospital stay	8.2±5.7	8.6±5.3	0.23
Reoperation	16 (5.1 %)	9 (5.7 %)	0.83
Early period postoperative mortality	3 (1 %)	2 (1.3 %)	1
Readmission	13 (4.1 %)	12 (7.6 %)	0.13
Follow up (years)	5.3±4.5	5±4.2	0.4
Local recurrence	10 (3.2 %)	3 (1.9%)	0.56
Cancer specific mortality	40 (12.7 %)	25 (15.9 %)	0.55
Complications
Bleeding	9 (2.9 %)	7 (4.5 %)	0.69
Ureteral injury	3 (1 %)	1 (0.9%)	1
Wound infection	12 (3.8 %)	12 (7.6 %)	0.11
Stoma complication	1 (0.3 %)	1 (0.6 %)	1
Anastomotic leak *	5 (2.1 %)	14 (8.9 %)	0.0003

‡median (range) * The cases, which had no anastomosis, excluded from the leak percentage calculation