How Is Pancreatic Cancer Staged?
Pancreatic cancer is typically staged using the TNM system. This system evaluates three key factors:
- T (Tumour): This refers to the size and location of the primary tumour in the pancreas.
- N (Node): This indicates whether the cancer has spread to nearby lymph nodes.
- M (Metastasis): This shows whether the cancer has spread (metastasised) to distant organs, such as the liver or lungs.
Based on these factors, pancreatic cancer is assigned a stage, ranging from 0 to IV. Lower stages indicate an earlier, more localised cluster of cancer cells, while higher stages reflect more advanced cancer that has spread further within the body.
What Is Stage 0 Pancreatic Cancer (Carcinoma in Situ)?
Stage 0 pancreatic cancer, also known as carcinoma in situ, is the earliest form of the disease. At this point, abnormal cells are confined to the lining of the pancreatic ducts and have not invaded deeper tissues or spread outside the pancreas.
Most people with stage 0 pancreatic cancer experience no symptoms. This stage is often discovered incidentally during medical procedures performed for other reasons. If left untreated, these abnormal cells can gradually develop into invasive cancer.
How Does Pancreatic Cancer Appear in Stage I?
In stage I, the tumour is confined to the pancreas and has not spread to any lymph nodes or distant sites. This stage is divided into two sub-stages based on tumour size:
- Stage IA: The tumour is 2 centimetres (cm) or smaller.
- Stage IB: The tumour is larger than 2 cm but not more than 4 cm.
As the cancer is still localised, surgical removal of the tumour, such as through a Whipple procedure, may be possible. However, symptoms of stage I pancreatic cancer may still be absent or vague, which often delays diagnosis and identification.
What Does Stage II Pancreatic Cancer Involve?
Stage II pancreatic cancer means the disease has begun to progress beyond its earliest stage but remains potentially treatable with surgery in selected cases. At this stage, the cancer may present in one of two main ways. The tumour may extend slightly beyond the pancreas into nearby tissues, such as the duodenum or bile duct, without involving major blood vessels. Alternatively, the tumour may still be confined to the pancreas, but cancer cells have spread to a small number of nearby lymph nodes.
Despite this progression, surgical removal of the tumour may be possible depending on the exact location, size and relationship to surrounding structures.
What Characterises Stage III Pancreatic Cancer?
Stage III pancreatic cancer indicates a more extensive local spread of the disease. The tumour has typically grown into major blood vessels or nerves near the pancreas. It may have also spread to a significant number of lymph nodes.
At this stage, the cancer is typically not resectable, meaning surgical removal becomes more challenging. Thus, the treatment often focuses on controlling the disease through chemotherapy, radiation or a combination of both to shrink the tumour or slow its growth.
When Is Stage IV Pancreatic Cancer Defined?
Stage IV is the most advanced stage of pancreatic cancer. This means the cancer has metastasised or spread to distant organs. The most common sites for metastasis include the liver, lungs, bones and the lining of the abdomen (peritoneum).
Treatment focus for stage IV pancreatic cancer typically shifts toward palliative care, which aims to relieve symptoms and maintain quality of life for the patient. These treatments may include chemotherapy, targeted therapy and pain management.
How Do Doctors Determine the Stage of Pancreatic Cancer?
To stage pancreatic cancer accurately, doctors use a range of diagnostic tests and procedures. Together, these assessments help identify the size of the tumour and determine how far the disease has spread.
Imaging Scans
Computed tomography (CT) scans and MRIs are used to create detailed images of the abdomen. These scans help identify the tumour's size and whether it has spread to other organs like the liver. A positron emission tomography (PET) scan can also be used to detect the spread of cancer throughout the body.
Biopsy
A small tissue sample is taken from the tumour, often during an endoscopic ultrasound (EUS), and examined under a microscope. This is used to confirm the presence of cancer cells.
Blood Tests
Blood tests may be ordered to check for tumour markers, such as CA 19-9. High levels of this substance may non-definitively indicate the presence of pancreatic cancer.
Surgical Exploration
In some cases, a surgeon may need to perform a procedure called a laparoscopy. A thin tube with a camera is inserted into the abdomen to get a direct look at the pancreas and surrounding areas. This helps confirm whether the tumour can be surgically removed.
