Recently, while performing case-finding, I came upon a path report with a diagnosis of a gastrointestinal stromal tumor, or GIST. After discovering that there was no statement of malignancy I contacted my pathologist and asked for a clarification. What seemed like a simple step ultimately led me to learn more about these tumors and how the pathologic and clinical understanding of GIST tumors is changing.
GISTs occur anywhere along the length of the gastrointestinal (GI) tract and in extravisceral sites (or outside of the internal organs that are enclosed within a body cavity, such as the abdomen, thorax, pelvis or endocrine organs) such as the omentum, mesentery, pelvis and retroperitoneum. GISTs tend to arise from the wall of the GI tract and extend inward toward the mucosa, outward toward the serosa, or in both directions. As the lesions invade the wall of the GI tract they may cause ulceration of the overlying mucosa. Infrequently there will be invasion through the muscularis with involvement of the mucosa. Anatomic location is a prognostic indicator and tumors arising in the stomach have a more favorable prognosis. An accurate anatomic location, ulceration, level of mucosal invasion, and extent of disease is important to the patient’s prognosis and the Cancer Registrar should carefully document this information.
For a GIST tumor to be reportable, the standards tell us that there must be a pathologic or clinical documentation of malignancy. When the cancer registrar encounters a case that does not specifically state whether the tumor is malignant or not they should seek clarification from the pathologist and/or clinician. SEER SINQ 20100014 has listed a number of scenarios to use when it is not certain whether a GIST is reportable or not.
Understanding the etiology of GIST tumors will help the registrar not only in case-finding, but also in coding, abstracting and follow-up surveillance of GIST tumors. Cancer Registrars can enhance their knowledge of this type of malignancy and its behavior through a number of online resources, such as:
- National Cancer Institute (NCI) – “Gastrointestinal Stromal Tumors Treatment PDQ“
- American Cancer Society – “Do We Know What Causes Gastrointestinal Stromal Tumors?”
- American Cancer Society – “How are Gastrointestinal Stromal Tumors Staged?”
- The University of Texas, M.D. Anderson – “GIST 101 – Understanding Your Pathology Report“ (Power Point slide deck)
- GIST Support International – “What is Needed to Diagnose GIST?”
- GIST Support International – “Prognosis for GIST (Risk of Recurrence or Metastatsis)” (includes AJCC 7th Edition staging info)
- GIST Support International – “Pathology Reports for GIST” (great resource to use with SEER SINQ scenarios)
- NCCN Task Force Update (JNCCN) – “Update on the Management of Patients with Gastrointestinal Stromal Tumors” (article)
Even with all these great resources, however, you may find yourself in a situation where your pathologist states that all GISTs are to be considered malignant unless otherwise documented. So, what should a registrar do in this situation?
If your pathologists feel that the scientific evidence supports the reportability of ALL GIST tumors in your facility, unless specifically identified as a benign tumor, you CAN collect and report these cases. However, to support your actions you should ask for their statement in writing, including their clinical and pathologic rationale for doing so. This document can be presented to your Cancer Committee for review and then included in your Registry’s Policy and Procedure Manual. Note: we are NOT advocating that Registrar’s ignore or habitually not follow the standards, rules and guidelines. However, we are encouraging the Registrar to become knowledgeable and to seek the input and advice of the scientific and clinical experts in their facilities and nationwide.
GIST tumors spread by the shedding of the tumor cells into the bloodstream. While there are new studies and tests under development and the use of tumor markers are increasing (as evidenced in the resources listed above) the healthcare and research communities are now studying GIST tumors in greater detail that may impact how registries report these in the future. Once released into the bloodstream the cells may migrate and not manifest signs or symptoms of active, recurrent or metastatic disease for years and pathologists are now taking a more conservative approach to reporting a benign versus malignant diagnosis to GIST tumors.
Cancer Registrars are faced with situations quite often and the best approach is to: 1) undertake a personal course of study in the tumor type, its etiology, disease progression and clinical manifestation process; and 2) consult with the pathologists and clinicians to better understand the diagnosis and treatment of the patient with this type of tumor.