A multidisciplinary approach to the diagnosis of pancreatic cancer and (more importantly) the determination of resectable disease is essential.
Surgical resection is currently the only curable treatment approach; therefore, determining whether or not a patient’s cancer is resectable is crucial. The diagnostic team should include surgeons, radiologists, medical oncologists and radiation oncologists.
A mass in the pancreas is usually detected in symptomatic patients using an endoscopic ultrasound (EUS) or spiral CT of the pancreas (See Tests below). CT scans should be done using a specific pancreas protocol. If the mass appears confined to the pancreas, then surgery is performed. Here, surgery serves both diagnostic and therapeutic roles. Biopsy-proven malignancy is NOT required prior to surgery in patients with a documented pancreatic mass.
When metastatic disease is present, or if the patient appears to have unresectable disease in an EUS and/or CT scan, then a biopsy of the mass with a fine needle aspiration (FNA) is performed. A positive biopsy for cancer IS required prior to administering systemic therapies such as chemotherapy. An EUS-directed FNA is preferred to a CT-guided biopsy, as CT-guided biopsies can lead to seeding of the peritoneal cavity with tumor. If the first EUS-directed FNA is negative, it should be repeated to be certain that cancer is not present.
If a patient with suggestive symptoms does not have a pancreatic mass that is evident in an EUS or CT scan, then an endoscopic retrograde cholangiopancreatography (ERCP) can be done to detect the mass prior to surgery or FNA. If ERCP cannot be successfully performed, then a magnetic resonance cholangiopancreatography (MRCP) may be done.
Pancreatic Cancer Tests
Once the diagnosis of pancreatic cancer is confirmed, the patient undergoes a wide variety of tests to evaluate the extent of disease, the prognosis for survival, and to establish baseline organ function prior to treatment.
The extent of pancreatic cancer is determined by:
- EUS and/or spiral CT scans of the pancreas (Note that these two tests are complimentary. EUS is better at establishing blood vessel and lymph node involvement.)
- ERCP in patients with indeterminate EUS or CT scans
- Chest imaging with either CT scan or chest X-ray to assess for spread to the lungs
The use of PET scanning is still being investigated in pancreatic cancer. PET stands for positron emission tomography, with the imaging provided by cellular uptake of fluorine-18-fluorodeoxyglucose. Viable cancer cells are able to take up this sugar, while dead or fibrotic cells will not. Small studies have shown that PET scans can detect distant metastatic disease in up to 16% of pancreatic cancer patients in whom CT scans did not demonstrate metastases. This would spare these patients the morbidity of undergoing surgery.
Patient prognosis is determined by:
- Evaluation of performance status
- Evaluation of co-morbid disease states, such as cardiovascular or liver disease
- Pre-operative CA 19-9
(Note that CA 19-9 is a tumor marker that is commonly elevated in pancreatic cancer. It is not tumor-specific; therefore, it is not used as a screening or diagnostic tool. Rather, after the diagnosis of pancreatic cancer is established, a baseline CA 19-9 is measured and then used to evaluate response to therapy.)
Baselines are established for the following:
- Complete blood count (almost all chemotherapy causes bone marrow suppression)
- Serum electrolytes
- Renal and liver function tests
Staging Pancreatic Cancer
Pancreatic cancer is staged with the typical I, II, III, and IV designations. In addition, the tumor is often given a histologic grade of 1, 2, 3, or 4. Grade 1 describes a well-differentiated cancer and a better prognosis, whereas grade 4 is an undifferentiated cancer and a poorer prognosis.
Although pancreatic cancer follows the TNM staging classification as described below, perhaps a more important determinant for long-term survival is resectabilty. Classification beyond this yields very little difference in overall survivals. Pancreatic cancer can be subdivided into four classifications: resectable, borderline resectable, locally advanced unresectable, and disseminated disease.
These are defined as follows:
- Resectable: No distant metastases; No evidence of direct tumor extension to the celiac axis or mesenteric arteries; No involvement or compression of the superior mesenteric and portal veins.
- Borderline Resectable: Unilateral impingement of the superior mesenteric vein; Limited involvement of the inferior vena cava; adrenal, colon, or kidney invasion.
- Locally Advanced Unresectable: Encasement of the celiac or mesenteric arteries; occlusion of the superior mesenteric or portal veins; invasion or encasement of the aorta or inferior vena cava; encasement of the liver; rib or vertebral invasion; involvement of lymph nodes beyond the surgical field of resection.
- Disseminated Disease: Distant metastases present; By far the most common site of metastases is the liver.
Stages of Pancreatic Cancer
The stage I through IV descriptors for pancreatic cancer are listed below. Note that stages I and II are also divided into two sub-stages, designated A and B, based upon the extent of disease and organs involved.
- Stage IA: Tumor less than 2 cm and limited to the pancreas
- Stage IB: Tumor greater than 2 cm and limited to the pancreas
- Stage IIA: Tumor extends beyond the pancreas BUT no involvement of the celiac axis or superior mesenteric artery.
- Stage IIB: Tumor size as IA, IB or IIA, AND regional lymph nodes are involved with tumor.
Note that all of the above stages are considered to be potentially resectable, depending upon other factors as discussed above.
Stage III: Tumor involves the celiac axis or superior mesenteric artery. This tumor is considered unresectable.
Stage IV: Distant metastases are present. Note that if cancer cells are found in washings obtained during surgical resection, the patient should be treated as stage IV.