The Long-term Gastrointestinal Functional Outcomes Following Curative Anterior Resection in Adults With Rectal Cancer: A Systematic Review and Meta-analysis

BACKGROUND: Significant variability and a lack of transparency exist in the reporting of anterior resection outcomes. OBJECTIVES: This study aimed to qualitatively analyze the long-term functional outcomes and assessment tools used in evaluating patients with rectal cancer following anterior resection, to quantify the incidence of these outcomes, and to identify risk factors for long-term incontinence. DATA SOURCES: MEDLINE, Embase, and CINAHL were searched using the terms rectal neoplasms, resection, and gastrointestinal function. STUDY SELECTION: The studies included were in English and evaluated adults with rectal cancer, curative anterior resection, and a minimum 1-year follow-up. Patients with recurrent/metastatic disease were excluded. Of the 805 records identified, 48 articles were included. INTERVENTION: The intervention performed was anterior resection. MAIN OUTCOME MEASURES: The main outcome measure was incontinence (gas, liquid stool, and solid stool). RESULTS: The histories of 3349 patients from 17 countries were summarized. Surgeries were conducted between 1978 to 2004 with a median follow-up of 24 months (interquartile range, 12, 57). Sixty-five percent of studies did not use a validated assessment tool. Reported outcomes and incidence rates were variable. The reported proportion of patients with incontinence ranged from 3.2% to 79.3%, with a pooled incidence of 35.2% (95% CI 27.9, 43.3). Risk factors for incontinence, identified by meta-regression, were preoperative radiation 0.009 and, in particular, short-course radiation (P = .006), and study quality (randomized controlled trial P = .004, observational P = .006). LIMITATIONS: The meta-analysis was limited by the significant heterogeneity of the primary data. CONCLUSIONS: Functional outcomes are inconsistently assessed and reported and require common definitions, and the more regular use of validated assessment tools, as well. Preoperative radiation and, in particular, short-course radiation may be a strong risk factor for incontinence; however, further studies are needed.