Radiation Oncology/Pancreas/Overview
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Epidemiology
edit- 4th leading cause of cancer-related death in men and women (http://apps.nccd.cdc.gov/uscs/toptencancers.aspx)
- Estimated 31,000 deaths in 2004. (12.3 per 100,000 population)
- Incidence 10th for males, and females. Males: 13.1 per 100,000, Females: 10.2 per 100,000. http://apps.nccd.cdc.gov/uscs/toptencancers.aspx
- Incidence stable over past 20 years but has increased 3-fold since 1920
- Higher incidence in African Americans and males.
- Incidence peaks in 7th and 8th decades. Very uncommon before age 40.
- Risk factors are smoking, high fat diet, obesity.
- 60-80% of patients had diabetes diagnosed within the preceding 2 years.
Anatomy
edit- Divisions of the pancreas include the head, uncinate process, neck, body, tail
- Duct of Wirsung is pancreatic duct located in substance of pancreas and draining to common bile duct
- Anatomic Landmarks
- Celiac axis originates at T11-12
- SMA originates at L1 vertebral body (usually 1cm below celiac axis)
- Nodal drainage
- Pancreatic head - ant/post pancreaticoduodenal nodes, hepatoduodenal ligament nodes (including porta hepatis), SMA nodes
- Pancreatic body/tail - splenic artery nodes, celiac nodes, SMA nodes, paraaortics, inf pancreatic nodes
Pathology
edit- Adenocarcinoma
- Neuroendocrine 1-2%
- Cystic neoplasms (serous cystadenomas, mucinous cystic neoplasms) <10%
- Intraductal papillary mucinous tumors
- Solid pseudopapillary tumors
- Acinar cell
- Squamous cell
- Primary lymphoma of the pancreas 1%
Patient characteristics
edit- 80% have unresectable disease
- 52% are Stage IV
- 5-year overall survival is lowest of any cancer
- Survival with resection: 48% (1-year), 24% (2-year), 17% (3-year)
- Survival without resection: 23% (1-year), 9% (2-year), 6% (3-year)
Tumor markers
edit- CA 19-9 - has 70% sensitivity, 87% specificity when using a cutoff of 70 U/mL. Elevated in benign conditions as well, such as cholangitis. But the higher the CA 19-9, the more likely to have cancer. The pretreatment level is prognostic. A decreasing value after treatment with surgery, XRT, or chemo associated with better survival.
Prophylactic Hepatic Irradiation
edit- Tochigi, 2005 (Japan) (1994-2003) PMID 15995813 -- "Prophylactic hepatic irradiation following curative resection of pancreatic cancer." (Hishinuma S, J Hepatobiliary Pancreat Surg. 2005;12(3):235-42.)
- Retrospective. 65 patients, 34 with prophylactic hepatic irradiation (PHI), 31 without. RT dose 19.8-22.0 Gy + CI 5-FU
- Complications: 32/34 completed RT; 1 liver abscess, 1 death from hepatic failure without mets
- Liver failure: better in PHI group (p=0.05); Survival: better in PHI group (p=0.0002)
- Hopkins, 1997 (1991-1995) PMID 9193189 -- "Pancreaticoduodenectomy for pancreatic adenocarcinoma: postoperative adjuvant chemoradiation improves survival. A prospective, single-institution experience." (Yeo CJ, Ann Surg. 1997 May;225(5):621-33; discussion 633-6.). See above. No benefit.
- RTOG 8801 (1988-89) PMID 1571912 -- "High-dose local irradiation plus prophylactic hepatic irradiation and chemotherapy for inoperable adenocarcinoma of the pancreas. A preliminary report of a multi-institutional trial (Radiation Therapy Oncology Group Protocol 8801)." (Komaki R, Cancer. 1992 Jun 1;69(11):2807-12.).
- 79 pts w/ unresectable, inoperable, or recurrent T1-3 adenoCA of pancreas. Tx'd w/ 6120 cGy to pancreas + simultaneous 2340 cGy prophylactic hepatic irradiation. Pts received concurrent 5FU.
- Hepatic metastases documented in 32%, local progression in 73%, abdominal spread in 27%
- 2 grade 5 complications (1 hepatic failure), 9 grade 4 complications (mostly hematologic)
- Conclusion: PHI may reduce frequency of hepatic metastases, but local progression and abdominal spread ultimately uncontrollable.