Clinical Implications of Microsatellite Instability in Rectal Cancer

COLON AND RECTAL SURGERY that a probiotic would reduce abdominal pain in patients with chronic symptomatic diverticular disease.

Hospital-Based Quality Assessment of Rectal Cancer Care Using the National Cancer Data Base Enobong Efiong, MD, Christie Buonpane, MD, Marcus B Fluck, Marie A Hunsinger, Kevin Long, MD, Christopher J Buzas, Mohsen Shabahang, MD, FACS, Joseph A Blansfield, MD, FACS, Kristen Halm, MD Geisinger Medical Center, Danville, PA

METHODS: We conducted a single-center, double-blind, placebocontrolled trial of probiotic treatment (Symprove) in adult patients with symptomatic diverticular disease. We randomly assigned 143 patients to receive 1 mL/kg/day of probiotic liquid (72 patients) or placebo (71 patients) daily for 3 months. The primary endpoint was abdominal pain. Secondary endpoints included 9 abdominal symptoms, relief from recurrent episodes of acute diverticulitis, and progression to elective surgery for diverticular disease.

INTRODUCTION: Management of rectal cancer is complex, requiring coordination of multiple providers. National Comprehensive Cancer Network (NCCN) guidelines, developed for standardization and quality improvement, recommend a multimodal approach. This study analyzed national rates of compliance with NCCN recommendations, assessed factors affecting compliance, and evaluated whether compliance with evidence-based guidelines improved overall survival (OS).

RESULTS: One hundred twenty patients completed the trial. Groups were well matched. Pain scores decreased in both groups on treatment, but did not improve significantly for patients on Symprove as compared with placebo (p¼0.11). The probiotic improved secondary endpoints of constipation and diarrhea significantly (p<0.04) more than the placebo. More patients on placebo had a self-reported episode of acute diverticulitis during the trial (8 vs 3 patients on Symprove, p¼0.12). Median time to acute diverticulitis after initiation of the trial was 33 days (interquartile range 15-53). Five patients underwent elective sigmoidectomy within 3 months of trial completion, with no difference between patients on Symprove and patients on placebo.

METHODS: This is a retrospective review of adults diagnosed with clinical stage III disease, T3N0 or T4N0 rectal cancer using the National Cancer Data Base. Patients were classified as compliant if they underwent preoperative chemoradiation before surgical resection. Clinicopathologic variables were analyzed using univariate and multivariate models. RESULTS: A total of 23,180 patients were analyzed; 12,765 (55.1%) were compliant. A multivariate logistic regression model showed that compliance decreased as age increased (odds ratio [OR] 0.87, 95% CI: 0.84-0.90). Compliance also was lower in black patients compared with white patients (OR 0.79, 95% CI 0.71-0.87), in patients with a Charlson Comorbidity Index of 2 or greater (OR 0.75; 95% CI 0.65-0.89), and in patients who were not insured (p<0.0001). Academic research and Integrated Network Cancer Programs were most likely to be compliant (OR 1.62, 95% CI 1.46-1.8 and OR 1.87, 95% CI 1.62-2.16, respectively). After propensity matching, a significant improvement in overall survival was seen in the compliant group (p<0.0001).

CONCLUSIONS: Multi-strain liquid probiotic did not improve abdominal pain scores significantly, but significantly improved some other symptoms associated with chronic diverticular disease. Symprove may be a beneficial treatment for patients with symptomatic, nonacute diverticular disease. Clinical Implications of Microsatellite Instability in Rectal Cancer Georgios Karagkounis, MD, Brandie Heald, David Liska, MD, Thomas Plesec, MD, Charis Eng, MD, PhD, James M Church, MD, FACS, Matthew F Kalady, MD, FACS Cleveland Clinic, Cleveland, OH

CONCLUSIONS: Adherence to NCCN guidelines for rectal cancer patients improves survival. Compliance nationwide could be improved, especially for older patients, minorities, and patients without insurance. More studies will need to be performed to identify factors that hinder compliance.

INTRODUCTION: Microsatellite instability (MSI) is a prognostic marker and a harbinger for Lynch syndrome (LS) in colorectal cancer (CRC); however, most knowledge revolves around colon cancer. This study reviews an MSI-based universal screening program for LS among patients with rectal cancer. METHODS: Our institution has performed universal screening for LS of resected CRC patients since April 2009. Patient demographics, tumor characteristics, and screening results were reviewed. MSI-high (MSI-H) patients were matched 1:5 with microsatellite stable (MSS) patients on age, sex, stage, and treatment. Oncologic outcomes and response to neoadjuvant chemoradiation (CRT) were compared using t, chi-square, and log-rank tests.

Randomized Double-Blind Placebo-Controlled Trial of a Multi-Strain Probiotic in Treatment of Chronic Symptoms in Diverticular Disease Charlotte L Kvasnovsky, MD, MPH, Ingvar Bjarnason, MD, Ana Nora Donaldson, PhD, Roy Sherwood, PhD, Savvas Papagrigoriadis, MD, FRCS King’s College Hospital, London, UK, University of Maryland Medical Center, Baltimore, MD

RESULTS: Eight hundred eight consecutive patients with rectal adenocarcinoma (mean age 60.6 years, 38.2% female) underwent LS screening. Twenty-five tumors (3.1%) were MSI-H, and there was no correlation with age or sex. Among MSI-H cancers, 11 (44%) patients were genetically confirmed to have LS, and 6

INTRODUCTION: Diverticular disease is a significant burden on health care systems without agreed on or standardized treatment recommendations. Although some patients may benefit from elective surgery, the majority have milder disease. We hypothesized

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http://dx.doi.org/10.1016/j.jamcollsurg.2016.06.071 ISSN 1072-7515/16

Vol. 223, No. 4S1, October 2016

(24%) patients had a putative diagnosis of LS based on mismatchrepair protein loss. Therefore, at least 68% of MSI-H rectal cancers patients had LS. There was no difference between MSI-H and MSS tumors in pathologic complete response rates (3/9 vs 10/45, p¼0.78) or favorable response rates (6/9 vs 25/45, p¼0.81) after neoadjuvant CRT. Survival was similar for MSI-H and MSS cancers. CONCLUSIONS: Unlike in colon cancer, MSI-H is rare in rectal cancer and is not associated with age or sex. MSI-H in rectal cancers should alert clinicians toward further investigation for LS because it affects both the patient and family members. MSI-H does not confer worse response to CRT and should not restrict treatment decisions. Comparison of Surgical Incision Complete Closure vs Leaving Skin Open in Wound Class III and IV in Emergent Colon Surgery: Analysis Using the Targeted Colectomy American College of Surgeons NSQIP Database Anand Dayama, MD, Sumit Kumar, MBBS, Catherine A Fontecha, MD, Ahmed Mahmoud, MD San Joaquin General Hospital, French Camp, CA INTRODUCTION: Surgical site infection (SSI), intra-abdominal abscess, length of stay, and readmission are the leading parameters in evaluation of quality of care and resource use in colorectal surgery. We sought to study the effect of wound closure technique in emergent colon surgery with wound class III and IV. METHODS: We reviewed the NSQIP database from 2014 to identify patients undergoing emergent colectomy. Patients with open abdomen at the end of surgery and with wound class II were excluded. We compared surgical incision complete closure (SICC) with leaving skin open (SILSO). Variables including patient characteristics, operative techniques, and postoperative complications were selected for analysis. RESULTS: Of 2,451 patients undergoing emergent colectomy with wound class III/IV, the SICC cohort had 1,978 patients and the SILSO cohort had 473 patients. The incidence of deep SSI was 2.1% (2.4% SICC vs 1.1% SILSO, p ¼ 0.07), organ space SSI rate was 10.7% (10.5% SICC vs 11.6% SILSO, p ¼ 0.48), and the readmission rate was 10.8% (10.5% SICC vs 12.3% SILSO, p ¼ 0.25). Length of stay was significantly higher in the SILSO cohort: 12.46 days as compared with the SICC cohort’s 11.10 days (p ¼ 0.012).

Scientific Forum Abstracts

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INTRODUCTION: Improved rectal cancer treatment has increased the use of anal sphincter-preserving procedures (SPP). It is unclear whether African-American (AA) patients are benefitting from SPP at rates similar to those of non-African American (non-AA) counterparts. METHODS: We used the Nationwide Inpatient Sample for years 1998 to 2012 to compare AA and non-AA patients who had ICD-9 rectal cancer diagnosis codes and ICD-9 low anterior resection (LAR) or abdominoperineal resection (APR) procedure codes. We used a logistic regression model to adjust for age, sex, admission type, Elixhauser comorbidity index, and hospital factors such as size, location (urban vs rural), teaching status, and rectal-resection procedure volume. RESULTS: Our search identified 22,697 patients, 1,600 of whom identified as AA. After adjustment for age and sex, AA patients were less likely to undergo SPP compared with non-AA (odds ratio [OR] 0.71, 95% CI 0.64-0.78, p<0.0001). After further adjustment for Elixhauser comorbidity index, admission type, and hospital-specific factors, AA patients were still less likely to undergo SPP (OR 0.73, 95% CI 0.65-0.82, p<0.0001) (Table). Although the proportion of non-AA patients undergoing SPP increased during the study period (p¼0.03), this trend was not significant in AA patients (p¼0.18) (Table). Table. Odds Ratio (95% CI) of Receiving Sphincter-Preserving Procedure

Variable African American

Model adjusted for Model adjusted for age, sex, Elixhauser age, sex, Elixhauser score, admission Comorbidity Index type and hospital and admission Model adjusted factorsy type for age and sex* 0.71 (0.64-0.78)

0.71 (0.63-0.79)

0.73 (0.65-0.82)

1.17(1.11-1.24)

1.21 (1.14-1.28)

1.21 (1.13-1.28)

Elixhauser Comorbidity Index

0.98 (0.98-0.99)

0.99 (0.98-0.99)

Admission type (nonelective vs elective)

0.78 (0.72-0.85)

0.83 (0.76-0.91)

Sex (female vs male)

Hospital teaching status (nonteaching vs teaching)

1.11 (1.04-1.19)

Procedure volume (low vs very low)

1.21 (1.11-1.33)

Procedure volume (medium vs very low)

1.30 (1.18-1.44)

Procedure volume (high vs very low)

1.81 (1.62-2.02)

*Age was not statistically significant. y Age, hospital size, and hospital location (rural vs urban) were not statistically significant.

CONCLUSIONS: Surgical incision complete wound closure in emergent colon surgery with wound class III/IV is safe and effective. However, SILSO patients had longer lengths of stay, resulting in an increase in health care resource use.

CONCLUSIONS: African-American patients with rectal cancer have lower rates of SPP compared with non-AA patients, even after adjustment for patient- and hospital-specific factors. Further work is required to elucidate reasons for this concerning difference. Eliminating racial disparities in rectal cancer treatment should continue as a priority for the surgical community.

Decreased Use of Sphincter-Preserving Procedures among African-American Patients with Rectal Cancer Elliot G Arsoniadis, MD, Yunhua Fan, PhD, Stephanie L Jarosek, Wolfgang B Gaertner, MD, Genevieve B Melton, MD, PhD, FACS, Robert D Madoff, MD, FACS, Mary R Kwaan, MD, MPH, FACS University of Minnesota, Minneapolis, MN

Development of a Clinically Actionable, Longitudinal Incisional Hernia Risk Model after Colectomy Surgery Using All-Payer Claims Data Michael A Lanni, Michael G Tecce, Yenchih Hsu, Rachel R Kelz, MD, FACS, Justin P Fox, MD, MHS, John P Fischer, MD University of Pennsylvania, Philadelphia, PA