Pancreas

​ 5th leading cause of cancer mortality although only the 9th most common cancer Found primarily in Western countries.² Higher incidence in men than women and diagnosis is rare before age 45.³ || Known risks include tobacco use, diets high in animal fat, ionizing radiation, chemotherapy and exposure to 2-naphthylamine, benzene and gasoline.² || Diabetes and gastric outlet obstruction are also seen. May infrequently present with Trousseau's sign (migratory thrombophlebitis) or Courvoisier's sign (palpable gallbladder).² || || Grade 2-cells look somewhat like normal tissue (called moderately well differentiated or moderate grade). Grede 3-cells appear very abnormal (called poorly differentiated or undifferentiated or high-grade). They are likely to grow more quickly and more likely to spread."⁵ ||
 * Epidemiology: || Incidence of Disease:
 * Etiology: || The cause of pancreatic cancer is unknown.³
 * Signs & Symptoms: || ​Jaundice, pain, anorexia and weight loss are the most common presenting symptoms.¹
 * Diagnostic Procedures: || ​Main purpose of the workup is to determine resectability, establish histologic diagnosis, re-establish biliary tract outflow and circumvent gastric outlet obstruction. Exams to include H&P, upper GI, CT, US, ERCP, laparaoscopy or CT guided biopsy, CBC, CEA, CA19-9, glucose, amylase, lipase, bilirubin, alkaline phosphatase, LDH, LFT and endoscopy of the upper GI tract or endoscopic ultrasound.² ||
 * Histology: || Adenocarcinoma is the most common accounting for 80% of all cases. Other not so common histologi types include islet cell tumors, acinar cell carcinomas, and cytadenocarcinomas.⁷ ||
 * Lymph Node Drainage: || Lymphatics drain to the superior and inferior pancreaticoduodenal nodes, porta hepatis, and suprapancreatic nodes (see image below).¹, ⁴
 * Metastatic Spread: || Pancreatic cancer tends to spread to the liver and peritoneal cavity. Metastasis to these areas are more common for lesions located in the body and tail of the pancreas.¹ ||
 * Grading: ||  "Grade 1-cells look most like normal tissue (called well differentiated or low-grade).
 * Staging: || AJCC TNM staging system (see table below)¹, ⁶

||
 * Radiation Side Effects: || With external irradiation doses of 55 Gy or less to the duodenum or stomach, the risk of severe gastrointestinal complications varied from 5% to 10%. At doses greater than 55Gy, one-third of patients developed severe problems. In patients who received external irradiation plus iridium, the dose to the external field was limited to 50.4 Gy, but most received additional irradiation dose to the duidenum or stomach from the iridium boost. There was a 30% to 40% incidence of severe complications in the duodenum or stomach in this group of patients.¹ ||
 * Prognosis: || The overall suvival rate for this type of cancer is poor. Patients with adjuvent therapy have a survival rate of about 18 to 29 months.⁷

"Some patients with pancreatic cancer that can be surgically removed are cured."⁸ "However, in more than 80% of patients the tumor has already spread and cannot be completely removed at the time of diagnosis."⁸

"Chemotherapy and radiation are often given after surgery to increase the cure rate."⁸ "For pancreatic cancer that cannot be removed completely with surgery, or cancer that has spread beyond the pancreas, a cure is not possible and the average survival is usually less than 1 year."⁸ "Such patients might consider enrolling in a clinical trial (a medical research study to determine the best treatment)."⁸

"This cancer has a 5-year survival rate of less than 5%, meaning 95% of the people diagnosed with it will not be alive 5 years later."⁸ ||
 * Treatments: || ** General Management **


 * Standard surgical treatment for pancreatic cancer is the pancreatoduodectomy, or Whipple procedure.
 * For patients with unresectable tumors or metastatic disease, death usually results from hepatic failure due to biliary obstrction by local tumor extension or hepatic replacement by metastases.
 * For the small number of patients undergoing a potentially curative pancreatoduodenectomy, the three major sites of disease relapse are the bed of the resected pancreas, the peritoneal cavity, and the liver.
 * Current data do not suggest increased survival with the addition of chemotherapy, except when it is given in combination with irradiation.
 * Radiation Therapy Techniques **


 * In patients undergoing surgery, clips should be placed to mark the extent of the lesion for later external irradiation.
 * The patient should be supine during simulation and treatment.
 * The intent of treatment is to use multiple-field, fractionated enternal-beam techniques with high-energy photos to deliver 45 to 50 Gy to unresected or residual tumor, as defined by CT and clips, and to nodal areas at risk.
 * With lesions in the head of the pancreas, major node groups include the pancreaticoduodenal, porta hepatis, celiac, and suprapancreatic nodes.
 * The suprapancreatic node group is included with the body of the pancreas for a 3 to 5 cm margin beyond gross disease, but more than two-thirds of the left kidney is excluded from the AP/PA field because at least 50% of the right kidney is often in the field because of duodenal inclusion.
 * The entire duodenal loop with margin is included because pancreatic head lesions may invade the medial wall of the duodenum and place the entire circumference at risk.
 * With pancreatic body or tail lesions, at least 50% of the left kidney may need to be included to achieve adequate margins and include node goups at risk. Because inclusion of the entire duodenal loop is not indicated with these lesions, at least two-thirds of the right kidney can be preserved, but with tailored blocks, it is usually possible to cover pancreaticoduodenal and porta hepatis nodes adequately.
 * For head of pancreas lesions, the superior field extent is at the middle or upper portion of the T11 vertebral body for adequate margins on the celiac vessels.
 * The upper field extent is occasionally more superior with body lesions to obtain an adequate margin on the primary lesion.
 * With lateral fields, the anterior-field margin is 1.5 to 2.0 cm beyond gross disease. The posterior margin is at least 1.5 cm behind the anterior portion of the vertebral body to allow adequate margins on paraaortic nodes, which are at risk with posterior tumor extension in head or body lesions.
 * The lateral contrabution is usually limited to 18 to 20 Gy because a moderate volume of kidney or liver may be in the field.
 * After resection, AP-PA and lateral fields are designed on the basis of pre-resection CT primary tumor volumes, operative clip placement, and postoperative CT nodal volumes.
 * The only border that can be more restrictive is the anterior border on lateral fields, since the primary tumor has been resected. This border is determined by vascular or nodal boundaries as demonstrated on CT.¹

||
 * TD5/5: || Dose to the following organs should be considered:

Liver -- the whole liver can receive 20 to 30 Gy, with an upper threshold of 33 to 35 Gy. One-third to one-half of the liver volume can receive more than 40 Gy without complications. Kidney -- 1/3 can receive 50 Gy, 2/3 can receive 30 Gy, the whole kidney can receive 23 Gy. Spinal cord -- 45 Gy Stomach -- 1/3 can receive up to 60 Gy, 2/3 is 55 Gy, and the whole stomach tolerance is 50 Gy Small intestine -- 1/3 to 50 Gy and all to 40 Gy¹ || This is a 7-field IMRT composit plan. The dose is 4500cGy with a boost to 5040cGy. 9 || 1. Chao KS, Perez CA, Brady LW. //Radiation Oncology - Management Decisions,// 2nd ed: 383-394. Philadelphia, PA//:// Lippincott, Williams & Wilkins, 2002. 2. Coleman J and Quivey JM. Pancreatic Cancer. In: Hansen EK, Roach M. //Handbook of Evidence-based Radiation Oncology,// 1st ed: 230-239. New York, NY: Springer, 2007. 3. Lenards, N. //Fundamentals of Clinical Oncology for Medical Dosimetrists. ​// Course content - Pancreas, Slide 3. December, 2009. 4. Lenards, N. //Fundamentals of Clinical Oncology for Medical Dosimetrists. ​// Course content - Pancreas, Slides 4, 6. December, 2009. 5. The Health Resource, Inc. http://www.thehealthresource.com/cancer_info/pancreatic_cancer3.cfm. Accessed January 19, 2010. 6. Google Images. []. Accessed January 19, 2010. 7. Washington CM, Leaver D, eds. //Principles and Practice of Radiation Therapy, 2 //nd ed: 770-773. Philadelphia, PA: Mosby Inc, 2004. 8. Google Health. []. Accessed January 21, 2010. 9. Courtesy of Sherilee Griffin. Samaritan Regional Cancer Center. Corvallis, OR.
 * Planning Photos: || [[image:Pancreas_composite_plan.JPG width="439" height="642" caption=" "]]
 * References**

Ginnie is bright blue. Bridget is green. Sheri is brown. Zack is purple.