Colorectal cancer.pdf
•
1 like•4 views
Summary about colorectal cancer including Hx, examinations, ddx & Tx
Recommended
More Related Content
Similar to Colorectal cancer.pdf
Similar to Colorectal cancer.pdf (20)
More from عباس مشتاق
More from عباس مشتاق (19)
Recently uploaded
Recently uploaded (20)
Colorectal cancer.pdf
- 1. Colorectal cancer Etiology 1- Chromosomal instability pathway in colon cancer (KRAS), Tumor suppressor genes (APC, TP53) • APC gene mutation (loss of cellular adhesion and increased cellular proliferation) → KRAS gene mutation (unregulated cellular signaling and cellular proliferation) → TP53 and DCC gene mutation • Most cases of sporadic ColoRectal Carcinoma develop via this pathway. 2- Microsatellite instability pathway in colon cancer (Mutations in mismatch repair genes (MMR genes, e.g., MLH1 or MSH2) 3- Hypermethylation phenotype pathway in colon cancer 4- COX-2 overexpression Risk factors • Age > 40 years • Family history • Colorectal adenomas • Inflammatory bowel disease • Diabetes mellitus type 2 Protective factors • Long-term use of aspirin and other NSAIDs Clinical features CRC can be asymptomatic, particularly during the early stages. In General • Weight loss • Fever • Night sweats • Fatigue • Abdominal discomfort Rt-sided colon carcinomas (Cecum, ascending, Transverse) • Occult bleeding or melena • Iron deficiency anemia (due to chronic bleeding) • Diarrhea Lt-sided colon carcinomas (Splenic flexure, descending, sigmoid, or the rectosigmoid junction) More common because (fecal matter is more liquid in the proximal colon, Lt-sided Ca tend to obstruct the lumen more than right-sided Ca) . • Changes in bowel habits (size, consistency, frequency) • Blood-streaked stools • Colicky abdominal pain (due to obstruction) • Lifestyle ◦ Smoking ◦ Alcohol • Diet ◦ Obesity ◦ High-fat and low-fiber adenocarcinoma (95%)
- 2. Rectal carcinomas (≤ 15 cm from the anal verge) • Hematochezia • ↓ Stool caliber (pencil-shaped stool) • Rectal pain • Tenesmus Diagnostics 1- Digital rectal examination • Distal rectal cancers may be palpable 2- Flexible sigmoidoscopy with or without anoscopy • hematochezia • Age < 40 years 3- Complete colonoscopy and biopsy 4- CT colonography & IV or oral contrast 5- Double-contrast barium enema (Apple core lesion) 6- Laboratory studies • Carcinoembryonic antigen (CEA) • CBC Liver Metastases Treatment 1- Surgery for colorectal cancer A- Curative surgery • Surgery of primary tumor ◦Complete resection with clear margins (R0 resection) is associated with the best prognosis. • Regional lymph node dissection • Resection of metastases (liver and/or lung metastases B- Palliative surgery 2- Systemic therapy A- Chemotherapy regimens • FOLFOX • FOLFIRI • CAPOX B- Biologics • Anti-VEGF antibodies (e.g., bevacizumab) • EGFR antibodies (e.g., cetuximab) 3- Radiation therapy • Rectal cancer (standard treatment) • Colon cancer (Not a standard modality because of adverse effects on the small intestine)
- 3. Typical surgeries for colon cancer Type of resection Description Indication Hemicolectomy Right hemicolectomy • Resection of part of the distal ileum, the ileocecal valve, cecum, ascending colon, hepatic flexure, and proximal third of the transverse colon • Tumor in the cecum and ascending colon Extended right hemicolectomy • Right hemicolectomy and resection of the transverse colon • Tumor near the hepatic flexure or in the proximal or middle transverse colon Left hemicolectomy • Resection of the distal third of the transverse colon, the splenic flexure, descending colon, and sigmoid colon • Tumor in the descending colon Sigmoid colectomy • Resection of the sigmoid colon • Tumor in the sigmoid colon Subtotal or total abdominal colectomy • Resection of most of or the entire colon • Multifocal carcinomas • Underlying colonic disease Less commonly used techniques • Extended left hemicolectomy • Transverse colectomy • Anterior resection ﻻ ﺗ ﺒ ﺤ ﺚ ﻋ ﻦ ا ﻟ ﺴ ﻌ ﺎ د ة أ ﺻ ﻨ ﻌ ﻬ ـ ـ ـ ـ ـ ـ ﺎ - a