The same rules are used to assign diagnosis date for both non-malignant and malignant CNS tumors.

The rules are found in Commission on Cancer’s Facility Oncology Data Standards (FORDS), Section 2: Coding Instructions, pages 89 and 90. It is not unusual for a patient with a non-malignant CNS tumor to be diagnosed in a physician’s office and treated with watchful waiting. Several years may go by before the patient receives subsequent treatment at a health care facility in the form of surgery or radiation therapy or some type of systemic therapy. Also, non-malignant CNS tumors, especially meningiomas, often recur. The date of initial diagnosis should be recorded in the abstract, not the date of subsequent treatment or date of recurrence. Health records must be reviewed carefully to determine the initial date of diagnosis by a medical practitioner, regardless if the initial diagnosis was clinical or histologic.