Pancreatic Cancer

Overview

• Pancreatic cancer (cancer of the pancreas) is the fifth leading cause of cancer-related deaths in the United States and the incidence is increasing in India.⁴
• Pancreatic cancer is difficult to diagnose in the initial stages as there are no specific early symptoms. The early symptoms often present themselves in an unrecognisable manner and cannot be directly attributed to pancreatic cancer.
• Since the pancreas is located deep in the body and is hidden behind other organs, doctors cannot see or feel the tumors during routine examinations.
• Pancreatic cancer is often detected at an advanced stage and it progresses and spreads quickly. Advanced disease is difficult to treat resulting in low cure rates.

Types of Tumors

• Exocrine Tumors

These are the most common type of pancreatic cancer tumors. The cells that secrete digestive enzymes form the exocrine part of the pancreas. Most of the exocrine pancreatic tumors are malignant in nature.

A majority of the exocrine pancreatic tumors are adenocarcinomas which account for about 95% of the cases. Adenocarcinomas are tumors that originate from glands and from glandular structures: the pancreatic adenocarcinomas usually originate from the ducts of the pancreas, but may also develop from the cells that make the pancreatic enzymes (acinar cell carcinomas).

Other forms of ductal cancers of the exocrine pancreas include adenosquamous carcinomas, squamous cell carcinomas, and giant cell carcinomas. These types are differentiated based on the microscopic characteristics of the cancerous cells.

The treatment of exocrine pancreatic cancer is mostly based on the stage of the cancer, not its exact type.

Another important type of cancer is the ampullary cancer (or carcinoma of the ampulla of Vater). Ampullary cancer develops where the bile duct and pancreatic duct come together and empty into the duodenum which is a part of the small intestine in continuity with the stomach. These tumors often block the bile duct while they are still small and have not spread far. This blockage causes the accumulation of bile, leading to yellowing of the skin and eyes (jaundice) and can turn the urine dark. Because of this, ampullary cancers are usually detected at an earlier stage than most pancreatic cancers, resulting in a relatively better outcome than typical pancreatic cancers.

• EndocrineTumors

The cells that secrete hormones constitute the endocrine portion of the pancreas. Tumors of the endocrine pancreas are less frequent. Collectively they are known as neuroendocrine tumors, or more specifically, islet cell tumors. There are several subtypes of islet cell tumors that are named according to the type of hormone secreting cells they originate from:

• Insulinomas -arise from cells that make insulin
• Glucagonomas -from cells that secrete glucagon
• Gastrinomas -from cells that make gastrin (hormone released by stomach)
• Somatostatinomas- from cells that make somatostatin
• VIPomas come from cells that make vasoactive intestinal peptide (VIP)

These tumors are referred as "functioning" if they secrete hormones and "non-functioning" if they do not. Most functioning islet cell tumors are benign, while non-functioning tumors are more likely to be malignant. Treatment of these tumors depends on the specific type and stage (extent) of the tumor.