PANCRES CA NOTES 2023.pptx

GIT: PANCREATIC CANCERS AUG 2023  Location: Retroperitoneal space, behind the stomach, at the level of the 1st two lumbar vertebrae Surrounded by spleen, liver and small intestine. Size: about15.24 cm long, oblong and flat. 3 divisions: head, body and tail. Functions: digestion & regu...

GIT: PANCREATIC CANCERS AUG 2023  Location: Retroperitoneal space, behind the stomach, at the level of the 1st two lumbar vertebrae Surrounded by spleen, liver and small intestine. Size: about15.24 cm long, oblong and flat. 3 divisions: head, body and tail. Functions: digestion & regulating blood sugar. PANCREATIC CANCER: Epidemiology Incidence: USA ≈ 2% of all cancers diagnosis 2008: 37,680 new cases 4th leading cause of cancer-related deaths ≈ 34,290 deaths High mortality rate 1 of deadliest malignancies. Gender: slightly more common in men than in women Race: incidence and mortality rates > in African Americans than in whites. Age: rare < 40 years; common: 50- to 80-year-old age group. 70% of patients are > 70 years (median age at diagnosis of 72) 4 PANCREATIC CANCER: Aetiology Unknown Risk factors: Smokers: ↑ risk Genetic factors: Hereditary nonpolyposis colorectal cancer Familial breast cancer (BRCA2 mutation) Peutz-Jeghers syndrome linked to polyps and other cancers, p16 gene mutations in familial pancreatic cancer Hereditary pancreatitis Exposure to industrial chemicals (benzidine and beta napthylamine) Obesity Lack of physical activity Diets high in fats, red meat, and processed meat (bacon, sausage) Diets high in vegetables and fruits – lowers risk Type 2 (adult-onset) diabetes. 5 PANCREATIC CANCER: clinical presentation The majority of early symptoms are non-specific - most patients present with advanced disease. Abdominal pain Anorexia Weight loss. Jaundice Obstruction of biliary system - head of the pancreas tumours → excess bilirubin excretion in urine Less bilirubin entering the bowel Dark urine and light-colored stools Pruritis/itching. Severe back pain & weight loss (body/tail of the pancreas) 6 PANCREATIC CANCER: Detection & diagnosis FBC - may reveal anaemia Biochemical tests confirm obstructive jaundice. CA19.9 (serum tumour marker) – high in 60 & 90% of cases Endoscopic retrograde cholangiopancreatography (ERCP)  Evaluate the ampulla, obtain cytological specimens & biliary drainage. Abdominal CT Endoscopic ultrasound - small lesions, any nodal involvement; venous involvement. Endoscopic ultrasound-guided fine needle aspiration (EUS FNA) Laparoscopy - detect unsuspected peritoneal disease FDG-PET MRI - in selected patients - definition of vascular anatomy prior to surgery. Patient’s history Physical examination Palpable abdominal masses Palpable supraclavicular nodes or rectal masses - indicate peritoneal 7 spread. PANCREATIC CANCER: Pathology & staging Adenocarcinomas - 80% of pancreatic cancers. Other histologic types: Islet cell tumors Acinar cell carcinomas Cystadenocarcinomas Staging: TNM staging system (American Joint Committee on Cancer Staging of Pancreas Cancer) T1 – 3: confined to the pancreas, generally resectable. > 50% of patients have distant metastasis 8 at diagnosis PANCREATIC CANCER: Routes of spread Locally invasive. Lymph node involvement Direct extension into the duodenum, stomach & colon – common Hematogenous spread (liver via the portal vein) - common Propensity to invade other abdominal structures - peritoneal seeding of tumor cells common 9 PANCREATIC CANCER: Treatment techniques Surgery: Treatment of choice Contraindications: o Liver metastasis o Extra pancreatic serosal implantation o Invasion or adherence to major vessels Curative surgical procedure = pancreaticoduodenectomy (Whipple procedure): o Resection = head of pancreas, duodenum, distal stomach, gallbladder, and common bile duct o 5-year survival rate < 10% (median survival time of approximately 11 to 14 months)  High locoregional recurrence rate & high risk of distant metastases. Palliative biliary bypass procedures - unresectable tumors 10 PANCREATIC CANCER: chemoradiation Main modalities Adjuvant treatment in resected pancreatic tumors Preferred modality for: o Locally advanced o Unresectable tumours 11 PANCREATIC CANCER: Chemotherapy Primary treatment with radiation for unresectable disease. Common drug: Gemcitabine Different drug combinations and sequences are being investigated Continuous infusion 5-FU is still being used as part of some chemoradiotherapy regimens. Other drugs being explored: irinotecan, capecitabine, oxaliplatin, and paclitaxel. 12 PANCREATIC CANCER: Field design & OAR 4 - field technique (TV & draining lymphatics - surgical clips or CT. 3D CRT & IMRT 3D CRT - Coplanar and non-coplanar beams IMRT - unique beam directions Head of Pancreas lesion: AP/PA field volumes TV: tumour bed + draining lymphatics + celiac axis Sup: T10-11 Field width: entire duodenal loop and the margin extending across the midline on the left. Lateral field: 1.5- to 2-cm margin anteriorly beyond the known disease. Posteriorly: 1.5 cm behind the anterior vertebral body (incl. paraaortic nodes) Body/tail lesions: adequate margin on the primary tumor + splenic hilar nodes. 13 PANCREATIC CANCER: Field design & OAR Dose: o 45 to 50 Gy; 1.8-Gy/# fractions with o High-energy photons o Boost fields after 45 Gy. Dose-limiting structures: o Kidneys; liver; stomach; small bowel; spinal cord. Treatment planning considerations: Head of pancreas lesions: ≈ 50% of right kidney in the treated volume (PB 2/3 of left kidney NB) AP/PA fields: MLC /shielding blocks NB (kidneys, liver, and stomach) on the AP/PA fields Lateral field (PB spinal cord & small bowel). 14 PANCREATIC CANCER: Field design & OAR Patient positioning: Supine Arms above head Immobilisation devices – vacuum device/foaming cradle immobilisation Straighten the patient – lasers and lining up the patient (suprasternal notch, xiphoid, pubic bone) CT simulation: Contrast administered 30 minutes to 1 hour before the scan. Scan borders: - above the diaphragm to below the iliac crest Delineation: target volume, lymph nodes, porta hepatis, and superior mesenteric artery OAR: kidneys, liver, stomach, small bowel, and spinal cord 15 PANCREATIC CANCER: Field design Fluoroscopic simulation: Preliminary borders & isocenter are established and marked on the patient's skin. Renal contrast injected Reference AP and/or lateral film taken: Determine the kidney location relative to other structures. Design of custom shielding blocks for kidneys Patient instructed to drink barium for localization of the duodenum and stomach (for unresectable head of pancreas lesions) AP/PA & lateral radiographs taken. 16 PANCREATIC CANCER: side effects Acute: Nausea Vomiting Leukopenia Thrombocytopenia Diarrhea Stomatitis Long-term side effects: Renal failure - rare (improper shielding of the kidney) 17