Non-malignant Brain Tumors

On January 1, 2004, all cancer registrars in the United States will begin to identify and abstract benign and borderline tumors of the brain and central nervous system.

The collection of benign brain and central nervous system tumors is mandated by Public Law 107, 260, the Benign Brain Tumor Cancer Registries Amendment Act. Any central cancer registry funded by the National Program of Cancer Registries of the Centers for Disease Control is required to submit benign and borderline CNS cases to NPCR.

The SEER Program will also begin collecting benign CNS tumors as a research priority defined by two independent agencies within the National Institutes of Health. As a result, there will be 100% central registry participation in this effort.

The reason for reporting benign and borderline brain and CNS tumors are:

• Benign and borderline CNS tumors cause disruption in normal function similar to that caused by malignant CNS tumors.
• Location of a CNS tumor is as important as tumor behavior (benign or malignant) for morbidity and mortality.

In the early 1900's, the neurosurgeon Harvey Cushing made the observation that some brain tumors are malignant because of their histology, and some are malignant because of their location. By this he meant that in the early 1900's some tumors were not resectable and would result in the death of the patient because of mass effects on vital areas of the brain. In the past 100 years, with advances in microsurgery, radiation therapy, and earlier diagnosis, the maxim of Dr. Cushing still stands, although at a greatly diminished number.

The tumors, whether benign or malignant, produce clinical effects by similar mechanisms of mass effect, hemorrhage, seizure activity, and edema. Population-based data on benign brain tumors has not been routinely collected and has limited our present knowledge of these tumors to hospital case series of 10 to 20 cases. Long term follow-up in these studies are generally absent. Although these tumors are individually rare, patients with benign brain tumors represent an under-appreciated financial and health burden in the United States. These cases include those tumors arising in families with an inherited tendency to develop benign and malignant brain tumors, tumors arising from developmental abnormalities, morbidity from ruptured benign brain tumors, and eventual malignant transformation in a subgroup of patients with optic nerve gliomas.

Existing coding rules for brain and CNS tumors have been guided by the behavior of these tumors. With the change to a site definition to guide their collection, the ROC Benign Brain Tumor Subcommittee reviewed coding rules applicable to both non-malignant and malignant brain and CNS tumors. Recommendations applicable to the current rules guiding multiple primaries for malignant brain and CNS tumors are contained in a separate document and have been forwarded to the SEER Histology Coding Committee for review in 2003.