Radiation Oncology/Pancreas/Overview

Epidemiology

 * 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

 * 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

 * 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

 * 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

 * 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

 * 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.

Other Resources

 * ARRO Case - Borderline Resectable Pancreatic Cancer
 * ARRO Contour - Borderline Resectable Pancreatic Cancer
 * eContouring Webinar - GI malignancies with Karyn Goodman, M.D.