Name
COLORECTAL MALIGNANCY
DESCRIPTION
DETAIL
CAUSES β’ Undetermined; both genetic and nvironmental factors may contribute β’ Environmental - high dietary animal fat, low dietary fiber -------------------------------------------------------------------------- DIFFERENTIAL DIAGNOSIS β’ Strictures (ischemic, Crohn, diverticulosis) β’ Other neoplasms (prostatic carcinoma, lipoma, leiomyoma, sarcoma, others) β’ Infectious/inflammatory lesions (ameboma, tuberculoma, hemorrhoids) β’ Extrinsic masses (abscesses, Cysts / pseudocysts, phlegmons)LABORATORY β’ Positive fecal occult blood test β’ Anemia β’ Urinary 5-hydroxyindoleacetic acid (5-HIAA); elevated in carcinoid β’ Elevated plasma carcinoembryonic antigen (CEA) SPECIAL TESTS : Carcinoembryonic antigen - usually elevated with bulky tumor or metastases, useful in postoperative assessment IMAGING: β’ Computerized tomography - used to determine extent of pelvic involvement in rectal cancer; not usually necessary in colon cancer β’ Transrectal ultrasound - useful in defining extent of involvement by rectal lesions β’ Virtual colonography - using CT scanning technology the entire colon can be visualized. This does not replace the colonoscope as a means of visualizing the colon and rectum. DIAGNOSTIC PROCEDURES β’ Anoscopy - useful for anal canal visualization, biopsies β’ Proctoscopy/fl exible sigmoidoscopy with biopsy - used for distal lesions when complementary barium enema available for proximal colon β’ Colonoscopy with biopsy - for primary diagnosis, screening of high-risk patients and post-resection surveillance; consider as screening modality of choice in all patients Colorectal malignancy
TYPENOTES
SURGICAL MEASURES : β’ Surgical procedures - radical resection of tumor with wide margins; includes segments of normal colon, mesentery, lymph nodes β’ Right hemicolectomy for proximal tumors β’ Left hemicolectomy for descending colon cancers β’ Sigmoid colectomy for sigmoid cancers β’ Abdominoperineal resection with colostomy for cancers of distal rectum (within 5-7 cm of dentate line) β’ Preoperative or postoperative radiotherapy and chemotherapy: May improve outcome when used for rectal carcinoma β’ For carcinoma of anus - combined chemotherapy (5-fl uorouracil and mitomycin C) and radiotherapy. Convert to abdominoperineal resection for residual or recurrent tumor or consider salvage chemotherapy (5-FU + cisplatin). PATIENT MONITORING: * Adenocarcinoma (after remainder of colon is cleared of all lesions) . Colonoscopy - repeat in 1 year; then every 3 years . Carcinoembryonic antigen test, liver chemistries, fecal occult blood test - every 3 months for 2 years; then every 4 months for year 3; then every 6 months for year 4; then annually * Carcinoid: . 5-HIAA every 6 months x 2 years, then annually * Squamous cell carcinoma: . Clinical evaluation every 4 months x 1 year, then annually . Biopsy suspicious areas in anus, groin PREVENTION/AVOIDANCE: . Colonic polyps should be removed, examined microscopically. If benign, surveillance colonoscopy should be performed after 3 years, and if normal, every 5 years . Screening - asymptomatic population (screening modalities include colonoscopy, fl exible sigmoidoscopy, and air contrast barium enema [ACBE]) . Average risk (eg, > 50 years) - Flexible sigmoidoscopy every 5 years - Colonoscopy every 10 years - Barium enema every 5 years . High risk (history of polyps, personal history of colorectal cancer, family history of colorectal cancer, history of IBD, FAP [familial adenomatous polyposis], hereditary non-polyposis colon cancer) - Colonoscopy - Schedules vary depending upon underlying risk . Chemoprevention (use of medical agents to prevent the development of cancer) under investigation. Aspirin and COX-2 inhibitors have shown promise. POSSIBLE COMPLICATIONS : * Following resections: . Mortality 5-10% . Wound infection 5-15% . Anastomotic stricture/leak/abscess 2-5% . Pneumonia 5-10% . Urinary tract infection 5-20% * During chemotherapy or radiation therapy: . Stomatitis . Proctitis/diarrhea . Temporary loss of hair EXPECTED COURSE/PROGNOSIS: * Adenocarcinoma: Overall 5-year survival is 55% but relates to tumor stage in individual patients. Five year survival for colorectal adenocarcinoma by initial stage Stage 5-yearSurvival --------------------------------------------- I 92% II 70% III 50% IV 5% * Carcinoid: . Overall 5-year survival is 65% . Relates to tumor stage as in adenocarcinoma * Squamous cell carcinoma: . Overall 5-year survival is 79% Pediatric: Adenocarcinoma of colon occurs rarely in children; prognosis is very poor Geriatric: Coexistence of medical illness may complicate postoperative course
RELATED DISEASE
Not Available Disease
DISEASE
INVESTIGATION
STOOL ROUTINE, STOOL FOR OCCULT BLOOD, ULTRA SOUND WHOLE ABDOMEN - FEMALE, COMPLETE BLOOD COUNT, MRI, CT SCAN