Carcinoma rectum

Dr. vinayak lokareJMMC & RI

Etiology

• average lifetime risk - 6%• risk increases two- to fourfold history of or a

first-degree relative with colorectal cancer.• Inflammatory bowel disease (IBD)• Genetics –– familial adenomatous polyposis (FAP) - APC gene

on chromosome 5q21– hereditary nonpolyposis colorectal cancer

(HNPCC)

Anatomy

• divided into three portions • lower rectum -3 to 6 cm from the anal verge• midrectum - 5 to 6 to 8 to 10 cm• upper rectum - 8 to 10 to 12 to 15 cm• determination of the location of the boundary

between rectum and sigmoid colon is important in defining adjuvant therapy

anatomy

• upper extent of the rectum can be identified where the tenia spread to form a longitudinal coat of muscle

• The distance from the anal sphincter musculature is clinically of more importance than the distance from the anal verge, as it has implications for the ability to perform sphincter-sparing surgery

Lymphatic drainage

• Upper rectum - follows the course of the superior hemorrhoidal artery toward the inferior mesenteric artery

• Middle rectum - follow the middle hemorrhoidal artery

• lesions occur below the dentate line, the lymphatic drainage is via the inguinal nodes and external iliac chain

Types

• Macroscopic– Proliferative – Ulcerative– Tubular

• Microscopic – Adenocarcinoma – Colloid carcinoma– Squamous cell carcinoma

Clinical features

• Bleeding per rectum – mucous +/-• Alteration of bowel habits – increasing

constipation, early morning diarrhoea• Sense of incomplete defeacation• Intestinal obstruction• Pain• Loss of appetite ,weight loss , joundice , ascitis

Investigations

• USG abdomen• Proctosigmoidoscopy / biopsy • Colonoscopy • contrast CT of the pelvis and the abdomen• Endoscopic USG

• Chest X-ray• Liver function tests• Renal function tests• Baseline CEA levels

staging

• Dukes’ staging• A- limited to bowel wall• B-spread outside the bowel wall• C-involvement of lymph nodes• Astler- Coller modification• B1-infiltration into muscularis propria• B2- infiltration beyond muscularis propria into

serosa

• C1- lymph node involvement but did not penetrate the entire bowel wall

• C2- tumors that invaded lymph nodes and did penetrate the entire wall (C2).

TNM staging • TX- Primary tumor cannot be assessed • T0 - No evidence of primary tumor • Tis - Carcinoma in situ: intraepithelial or invasion of

lamina propria[*] • T1 - Tumor invades submucosa • T2 - Tumor invades muscularis propria • T3- Tumor invades through the muscularis propria into

the subserosa, or into nonperitonealized pericolic or perirectal tissues

• T4 Tumor directly invades other organs or structures and/or perforates visceral peritoneum[†]

• NX- Regional lymph nodes cannot be assessed N0- No regional lymph node metastasis

• N1 - Metastasis in 1 to 3 regional lymph nodes

• N2- Metastasis in 4 or more regional lymph nodes

• MX Distant metastasis cannot be assessed • M0 - No distant metastasis • M1 - Distant metastasis

• STAGE T N M DUKES[§] MAC[§]

• 0 Tis N0 M0 • I T1 N0 M0 A A

T2 N0 M0 A B1 • IIA T3 N0 M0 B B2 • IIB T4 N0 M0 B B3 • IIIA T1-T2 N1 M0 C C1 • IIIB T3-T4 N1 M0 C C2• IIIC Any T N2 M0 C C1/C2• IV Any T Any N M1 D

Treatment

Stage 1• TEM– EUS- T1, T2– <40% circumference involvement– Well- mod. Differentiated– HPR – no lymphatic / venous invasion

• posterior proctotomy- Kraske procedure – large posterior lesions– allows for the mobilization of the rectum and a

full-thickness local excision

• T2 lesions-– Adjuvant chemoradiation

• Endocavitary radiation therapy– T1 or T2 tumors less than 3 cm,– not poorly differentiated, – with no evidence of nodal involvement

• four rounds of 2,500 to 3,000 cGy each with 2 to 3 weeks between treatments

Stage 2 and stage 3

Preoperative • Chemo therapy – 5-FU(350mg/m2/day) for 5

days• Leucovorin(20mg/m2) for 5 days• 2cycles• Radiotherapy 5000cGy • Surgery after 4-6 wks

• Surgery • Upper rectum – anterior resection• Middle rectum – low anterior resection• Low rectum - low anterior resection / APR

• Adjuvant chemotherapy• 5-FU + leucovorin – 4 cycles

Stage 4

• Preoperative chemo radiation• APR• Post operative chemo / RT

radiotherapy

• Proximal – sacral prmontary• Distal – 2 cm below primary tumor mass• Lateral – pelvic wall• Posterior – sacrum • Anterior – posterior border of vagina /

prostate

• 5-FU based adjuvant chemotherapy has been the standard of care for advanced rectal cancer– 5-FU treats micrometastases– –5-FU acts as a radiosensitizer

• Continuous infusion has shown improved survival and increased time to relapse when compared to bolus therapy