The Importance of Accurate Diagnosis and Multimodality Therapy for Pancreatic Cancer
Pancreatic cancer (adenocarcinoma) develops from the cells lining the pancreatic duct (duct or ductal cells), which are involved in processing and transporting digestive enzymes through the pancreas to the intestine to aid in digestion of food (especially fats). Transformation of a duct cell into a cancer is a complicated process characterized by a number of genetic mutations.
These mutations are an area of active investigation in the quest for a technique for early diagnosis and more effective therapies that target the molecular profile of the cancer. We are in the process of developing a pancreatic cancer research unit at the Medical College of Wisconsin, which will be based on the study of human cancers removed during biopsy procedures and with surgery.
We have compiled a series of illustrations and CT scan images showing the staging of pancreatic cancer as well as some surgical illustrations.
Staging Pancreatic Cancer
At the time of diagnosis, there is often confusion (on the part of patients and physicians) regarding how to stage the disease, whether or not the pancreatic tumor can be surgically removed, and the role for chemotherapy, chemotherapy combined with chemoradiation and how to combine chemotherapy, radiation and surgery in the most effective way. If surgery is performed, it is important that the surgeon be prepared to do a more extended operation involving the adjacent blood vessels (superior mesenteric vein, portal vein). The following tables provide guidelines for staging and treatment and were developed by me and my colleagues at M. D. Anderson Cancer Center over the last decade.
The following is a Clinical/Radiographic Staging System used for Adenocarcinoma of the Pancreatic Head based on high quality computed tomography (CT) imaging (see accompanying illustrations). The American Joint Commission on Cancer (AJCC) has established a four tier staging system for most solid tumors. In general, stages I and II are able to be surgically excised, stage III is localized, but usually not able to be surgically excised, and stage IV refers to cancers that have spread to other parts of the body.
|Clinical Stage of disease||AJCC Stage||Tumor-Vessel Relationship on Computed Tomography|
|*Resectable (all 4 required to be resectable)||I / II||Normal tissue plane between tumor and vessel||Normal tissue plane between tumor and vessel||Normal tissue plane between tumor and vessel||Patent (may include tumor abutment or encasement)|
|Borderline Resectable (only 1 of the 4 required)||III||abutment||abutment||Abutment or short segment encasement||May have short segment occlusion if reconstruction possible|
|Locally Advanced (only 1 of the 4 required)||III||encasement||encasement||Extensive encasement with no technical option for reconstruction||Occluded with no technical option for reconstruction|
Abbreviations: CHA, common hepatic artery; SMV-PV, superior mesenteric vein-portal vein confluence
Definitions: abutment, ≤180° or ≤ 50% of the vessel circumference; encasement, >180° or > 50% of the vessel circumference
*Assumes the technical ability to resect and reconstruct the SMV, PV, or SMV-PV confluence when necessary. Others may consider tumor-vein abutment/encasement which results in deformity of the vein as borderline resectable.
**Assumes normal vascular anatomy; for example, encasement of the CHA is not a limitation in performing a whipple procedure when there is an uninvolved replaced right HA arising from the SMA.
The following table presents a general treatment schema used to guide stage-specific therapy for patients with adenocarcinoma of the pancreas.
|Clinical Stage of disease||AJCC Stage||Treatment Options|
|*Resectable||I / II||
- Resectable disease: the tumor can be surgically excised
- Borderline resectable disease: the tumor may be surgically excised after chemotherapy and chemoradiation if the patient tolerates the treatment well and there is evidence of tumor response
- Locally advanced disease: the tumor is not able to be surgically excised and in general, it is felt that surgery will never be possible.
- Metastatic disease: the tumor has spread (through the blood stream or in other ways) to other parts of the body, most commonly the liver, abdominal cavity and occasionally, the lungs.