17/02/2025
⭕️Carcinoma Re**um: A Concise Overview
🔴 Definition
Carcinoma of the re**um is a malignant tumor arising from the re**al mucosa, typically adenocarcinoma. It is the third most common cancer worldwide and requires a multidisciplinary approach for management.
🔴Epidemiology
🔹️Incidence: High in developed countries; increasing in younger populations
🔹️Age: Peak incidence in 6th–7th decade
🔹️Sex: Slight male predominance
🔹️ Risk Factors:
🔹️Dietary: Low fiber, high red meat, processed foods
🔹️Genetic: Familial adenomatous polyposis (FAP), Lynch syndrome
🔹️ Inflammatory: Long-standing ulcerative colitis, Crohn’s disease
🔹️ Lifestyle: Obesity, smoking, alcohol, sedentary lifestyle
🔹️ Previous history: Colore**al polyps, prior colore**al cancer
🔴Pathology
✅️ Histology:
• Adenocarcinoma (90%)
• Mucinous carcinoma, signet ring cell carcinoma (poor prognosis)
✅️Tumor Differentiation: Well, moderate, poor
✅️ Spread:
• Local: Circumferential and longitudinal extension within the re**al wall
• Lymphatic: Mesore**al, internal iliac, para-aortic nodes
• Hematogenous: Liver (most common), lungs
• Peritoneal seeding: Advanced cases
🔴Clinical Features
✅️Symptoms:
🔹️ Altered bowel habits (diarrhea/constipation, tenesmus)
🔹️ Re**al bleeding (hematochezia, melena in advanced cases)
🔹️ Mucus discharge
🔹️ Pelvic pain (advanced stage, local invasion)
🔹️ Incomplete evacuation sensation
🔹️ Weight loss, anorexia (late-stage)
✅️Signs:
🔹️ Digital re**al examination (DRE): Palpable mass, ulceration, induration
🔹️ Anemia (chronic blood loss)
🔹️ Hepatomegaly (if liver metastases)
🔴 Diagnosis
✅️ Clinical Suspicion:
🔹️ Any re**al bleeding or change in bowel habits in patients >40 years requires further evaluation.
🔴 Investigations:
✅️ Endoscopic Diagnosis:
🔹️ Colonoscopy with biopsy (gold standard)
🔹️ Flexible sigmoidoscopy (alternative for distal tumors)
✅️ ️Imaging for Staging:
🔹️ MRI pelvis (gold standard for local staging)
🔹️ CT abdomen & pelvis (metastatic workup)
🔹️ Endore**al ultrasound (ERUS): For T-staging in early tumors
🔹️ PET-CT scan: For suspected distant metastases
✅️️ Laboratory Tests:
🔹️Carcinoembryonic antigen (CEA): Tumor marker, useful for prognosis and follow-up
🔹️ Complete blood count (CBC): Anemia
🔹️Liver function tests (LFTs): Assess liver metastases
🔺️ Staging (TNM Classification – AJCC 8th Edition)
• T1: Tumor invades submucosa
• T2: Invades muscularis propria
• T3: Invades perire**al fat
• T4: Invades other organs/peritoneum
• N0: No lymph node involvement
• N1: 1–3 regional lymph nodes involved
• N2: ≥4 regional lymph nodes involved
• M0: No distant metastases
• M1: Distant metastases present
🔴Management
Multidisciplinary Approach (MDT) Involves:
• Surgical oncologist
• Medical oncologist
• Radiation oncologist
• Gastroenterologist
1. Surgical Treatment (Curative Intent for Localized Disease)
• Total Mesore**al Excision (TME) (Gold Standard):
• Low Anterior Resection (LAR): For upper/mid re**al tumors, preserves a**l sphincter
• Abdominoperineal Resection (APR): For low re**al tumors involving sphincter, requires permanent colostomy
• Transa**l Local Excision:
• For early T1 tumors without lymphovascular invasion
• Pelvic Exenteration:
• For locally advanced disease invading adjacent organs
2. Neoadjuvant Therapy (For Locally Advanced Tumors – T3/T4 or Node-Positive)
• Long-course chemoradiotherapy (CRT) (5-FU or Capecitabine + radiation)
• Short-course radiotherapy (SCRT) (alternative in select cases)
• Benefits: Downstages tumor, improves resectability, sphincter preservation
3. Adjuvant Chemotherapy (Postoperative – If High-Risk Features)
• Indications: T3/T4, N+ disease, positive margins
• Regimens:
• FOLFOX (5-FU, Leucovorin, Oxaliplatin)
• CAPOX (Capecitabine, Oxaliplatin)
4. Palliative Treatment (For Metastatic Disease – Stage IV)
• Systemic Chemotherapy:
• FOLFOX or FOLFIRI (Irinotecan-based)
• Targeted therapy (if KRAS wild-type):
• Cetuximab, Panitumumab (EGFR inhibitors)
• Bevacizumab (VEGF inhibitor)
• Surgical Resection of Metastases:
• Liver metastasectomy (if resectable)
• Palliative stenting for obstructing tumors
Complications
• Local:
• Obstruction → Bowel perforation → Peritonitis
• Fistula formation (rectovaginal, rectovesical)
• Bleeding
• Metastatic: Liver, lung, peritoneal carcinomatosis
• Postoperative:
• Anastomotic leak
• Pelvic abscess
• Bowel dysfunction (low anterior resection syndrome)
Follow-Up & Surveillance
• Every 3–6 months (first 2 years), then annually (up to 5 years)
• CEA monitoring
• Colonoscopy (1 year post-op, then every 3–5 years)
• CT scan for recurrence/metastases
🔴Prognosis
• 5-year survival rates:
• Stage I: 90%
• Stage II: 70–80%
• Stage III: 50–60%
• Stage IV: