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The Perioperative Risk of Neoadjuvant Radiotherapy Before Low-Anterior Resection for Rectal Cancer
Neil Bhayani*, Niraj J. Gusani, Tara M. Connelly, Joyce Wong, Evangelos Messaris
Penn State Hershey Medical Center, Hershey, PA
INTRODUCTION
Neoadjuvant radiotherapy (nRT) reduces local recurrence after rectal resection and low-pelvic anastomosis (low-anterior resection or LAR) for rectal cancers. Many surgeons believe that nRT also increases postoperative anastomotic leak, intra-abdominal abscess and sepsis. However, studies performed to date, many small and retrospective, have conflicting results. This analysis of a prospective multi-institutional cohort was performed to determine if nRT worsens postoperative infectious morbidity.
METHODS
Patients who underwent LAR for rectal cancer from 2005 - 2012 were extracted from the National Surgical Quality Improvement Program's prospective database. Emergent surgeries and patients with disseminated cancers were excluded. Incidence of abdominal abscess, indicative of anastomotic leak, sepsis, and other perioperative morbidity were compared between patients who received nRT within 90 days preceding surgery and those who did not.
RESULTS
1491 (26%) of 5719 patients received nRT. The nRT group was slightly younger (59 v. 62 yrs, p<0.0001) and less likely to have hypertension (41% v. 51%, p<0.001). In the nRT group, operative times were longer (209 v. 182 minutes, p<0.001); fecal diversion was more common (66% v. 28%, p<0.001), and laparoscopy was used less (22% v. 36%, p<0.001). Abdominal abscess, a proxy for anastomotic leak, was more common in the nRT cohort (7.6% v. 5.1%, p<0.001). On multivariate regression analysis, age, sex, steroid use, diabetes, and nRT were independent predictors of abdominal abscess. After controlling for these variables, as well as fecal diversion and laparoscopic surgery, nRT remained associated with increased odds of abdominal abscess (OR 1.43, 95%CI 1.1 -1.9, p=0.004). However, nRT was not associated with increased odds of septic shock, overall morbidity, major morbidity or death.
CONCLUSION
This is the largest study of outcomes after rectal resection with low-pelvic anastomosis (LAR) for rectal cancer. In this prospective, multi-institutional cohort, patients who received neoadjuvant radiation had a small, but real, increase in the rate of abdominal abscesses. Though nRT was an independent predictor of post-operative intra-abdominal abscess, it was not associated with septic shock or death. In patients who have undergone neoadjuvant radiation, surgeons should consider operative techniques which may help to diagnose (intraoperative leak testing) or mitigate (fecal diversion) anastomotic complications.
Population & Outcomes after LAR for Rectal Cancer
| LAR | LAR + nRT | |
| n=4228 (74%) | n=1491 (26%) | p-value |
| Age, median | 63 | 59 | <0.0001 |
| Male | 2408 (57) | 921 (62) | 0.02 |
| Body Mass Index | 27.3 | 27.1 | 0.4 |
| Smoking | 676 (16) | 297 (20) | 0.001 |
| Steroid Use | 54 (1.3) | 16 (1.1) | 0.01 |
| Co-Morbidities | | | |
| Chemotherapy | 64 (2) | 446 (30) | <0.001 |
| Hypertension | 2145 (51) | 615 (41) | <0.001 |
| Diabetes | 706 (17) | 224 (15) | 0.15 |
| Weight Loss >10% | 169 (4) | 117 (8) | <0.001 |
| ASA Class ≥3 | 2011 (48) | 660 (44) | 0.03 |
| Outcomes | | | |
| Any Morbidity | 914 (21.6) | 362 (24.3) | 0.1 |
| Abdominal Abscess | 216 (5.1) | 114 (7.6) | 0.001 |
| Sepsis | 175 (4.1) | 76 (5.1) | 0.3 |
| Shock | 78 (1.8) | 28 (1.9) | 0.03 |
LAR, Low-Anterior Resection; nRT, neoadjuvant radiotherapy; ASA, American Society of Anesthesiology
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