RECTAL CANCER

Course overview

COLON AND RECTAL CANCERS TOGETHER ARE THE THIRD MOST COMMONLY DIAGNOSED CANCER IN THE UNITED STATES AND THE SECOND DEADLIEST. RECTAL CANCER HAS DISTINCT ENVIRONMENTAL ASSOCIATIONS AND GENETIC RISK FACTORS DIFFERENT FROM COLON CANCER. THE INCIDENCE OF NEW CASES AND MORTALITY OF RECTAL CANCER HAS BEEN STEADILY DECLINING FOR THE PAST YEARS, ALTHOUGH NOTICED TO RISE IN RECENT YEARS ON YOUNGER ADULTS (LESS THAN 50 YEARS). THE TRANSFORMATION OF THE NORMAL RECTAL EPITHELIUM TO A DYSPLASTIC LESION AND EVENTUALLY AN INVASIVE CARCINOMA REQUIRES AN ACCUMULATION OF GENETIC MUTATIONS EITHER SOMATIC (ACQUIRED) AND/OR GERMLINE (INHERITED) OVER AN APPROXIMATELY 10 TO 15 YEARS PERIOD. TUMOR REGRESSION GRADE AFTER PRE-OPERATIVE THERAPY AND PATHOLOGICAL STAGING ARE THE MOST IMPORTANT PROGNOSTIC INDICATORS OF RECTAL CANCER. ALL NEWLY DIAGNOSED PATIENTS WITH RECTAL CANCER SHOULD BE UNIVERSALLY SCREENED FOR DNA MISMATCH REPAIR/MICROSATELLITE STATUS PRESENT IN UP TO 13% OF ALL SPORADIC RECTAL CANCER CASES. A CAREFUL HISTORY AND PHYSICAL EXAMINATION, INCLUDING A DIGITAL RECTAL EXAM, ARE PARAMOUNT ON CLINICAL SUSPICION. AN ENDOSCOPY EXAMINATION WITH RIGID SIGMOIDOSCOPY IS REQUIRED TO MEASURE THE DISTANCE FROM THE LESION TO THE ANAL VERGE (LESS THAN 15 CM) AND FOR TISSUE BIOPSY FOR PATHOLOGICAL CONFIRMATION OF RECTAL CANCER. THIS ACTIVITY REVIEWS THE CAUSE, PATHOPHYSIOLOGY, PRESENTATION, AND DIAGNOSIS OF RECTAL CANCER AND HIGHLIGHTS THE INTERPROFESSIONAL TEAM'S ROLE IN ITS MANAGEMENT.