Surgery of Primary Site
See the current version of the SEER Program Coding Manual under Section VII: First Course of Therapy for complete coding instructions for the surgery data items or Appendix C of the current version of the SEER Program Coding Manual for a complete listing of the CNS surgery codes and their descriptions.
Surgery for CNS tumors can be done to get a histological confirmation and/or relieve intracranial pressure (if present). Due to the location of some of the tumors, surgical intervention is not always possible. Also, preserving neurological function and the patient’s overall health many times will limit how much of the tumor can be surgically removed.
It can be difficult to remove an entire tumor in the CNS. Even if imaging doesn’t show any tumor left behind, there can be microscopic cells that can’t be seen. Clear margins are hard to achieve with brain tumors. Surgery codes for CNS tumors are based on the extent of the resection, including local, subtotal, radical, total, gross resection and, partial resection. Review of the operative report is crucial to determine the extent of a surgical procedure.
Note: The extent of the resection may not be found in the Operative report title. The extent of the tumor is found in the body of the operative report. Review of the entire operative report is needed.
| Surgical Procedure | Comments |
|---|---|
| Laser Interstitial Thermal Therapy (LITT) | A type of treatment that uses heat created by a laser beam to remove or destroy abnormal tissue, such as cancer tissue. During laser interstitial thermal therapy, an imaging test, such as MRI, is used to help guide a wire or catheter (thin tube) into the abnormal area of tissue. A laser inserted through the catheter creates heat, which destroys the abnormal tissue. Laser interstitial thermal therapy may be used to treat certain types of brain tumors, including tumors that have spread to the brain from other parts of the body, radiation necrosis (tissue death caused by radiation therapy), and some types of epilepsy. (NCI Dictionary of Cancer Terms)
If LITT is done and there is no tissue removed, code as local tumor destruction. If tissue is sent to pathology from the LITT procedure, code as Surgery, NOS. |
| Craniotomy | An operation in which a small hole is made in the skull or a piece of bone from the skull is removed to show part of the brain. A craniotomy may be done to remove a brain tumor or a sample of brain tissue. It may also be done to remove blood or blood clots from the brain, relieve pressure in the brain after an injury or stroke, repair a skull fracture or brain aneurysm (a bulge in a blood vessel wall), or treat other brain conditions. The piece of bone that is removed from the skull is usually put back in place after the surgery has been done. (NCI Dictionary of Cancer Terms
Review the operative notes to determine the type of resection, or if they only removed enough tissue to get a diagnosis. Remember: A craniotomy is not a surgical procedure. It is simply a way to get to the tumor. |
| Debulking | Sometimes the only surgical intervention that can be done is to “debulk” a tumor, which is removing as much of the tumor volume as possible in cases where it is not possible to remove the entire tumor.
These are categorized as a subtotal resection of tumor, lesion, or mass. |
| Gross Total Resection | This is a complete removal of all visible or “gross” tumor.
The “gross” is referring to the tumor that is visible to the eye, or can be detected on imaging. Post surgery, additional imaging will be done to determine if a gross total resection was achieved. |
| Gliadel Wafer Therapy | This type of therapy involves a surgical procedure (review operative report to determine type of surgery) AND placement of a small disc that contains carmustine (BCNU), which is a potent type of chemotherapy used to treat localized brain tumors.
The Gliadel Wafer is placed directly on the tumor bed after the surgical resection is done. This is an alternative to systemic chemotherapy. It is a type of targeted therapy. This type of therapy is provided for patients with high-grade gliomas (i.e., glioblastomas), or for patients with recurrent gliomas. The Gliadel Wafer therapy is coded as intraoperative chemotherapy. |
| Transsphenoidal surgery | Procedure that is used on base of skull tumors. Surgeon inserts an endoscope through the nose and the skull and into the lower part of the brain.
This procedure is commonly done for pituitary tumors and is coded as an excisional biopsy. (See Surgery codes for “All Other Sites.”) |
| Neuroendoscopy | A long thin tube called an endoscope, equipped with a light and camera, is used to access areas of the brain or spine through small openings instead of an open surgical procedure. It also provides greater flexibility in maneuvering around structures within the brain.
This is considered a minimally invasive type of surgery in contrast to the craniotomy that is normally done. Surgery of primary site would depend on the amount of tumor that was removed. This would require review of the operative report. |
Document surgery details in NAACCR Item #2610: Text-Dx Proc-Surg
Updated: September 23, 2026
Suggested Citation
SEER Training Modules: Surgery of Primary Site. U.S. National Institutes of Health, National Cancer Institute. Cited 24 September 2026. Available from: https://training.seer.cancer.gov.