Recent Treatment Options and Future Perspectives for Petroclival Tumors

Petroclival tumors have been treated by microsurgery without radiosurgery and by endoscopic surgery recently along the stream of “noninvasive” policy. This lecture will clarify what is the best option, by presenting several cases. The contents will be as follows:

Indication of Surgery Consider the natural history from the symptoms. Asymptomatic tumors are basically observed to know the growing speed. A large tumor showing minimal symptom means slow growing.

Selection of Surgical Approach (suboccipital, presigmoid, anterior petrosal, endoscopic TSA): Anterior petrosal approach is indicated definitely for tumors extending to the middle fossa and Meckel cave. Presigmoid approach is indicated for broad-based meningiomas along the pyramid. Suboccipital approach is for meningiomas attached on the tentorium or small tumors–invaded IAM.

Indication of endoscopic TSA will be enlarged in epidural lesions such as clival chordomas, but may be limited in subdural lesions in the midline. Future technical advance on surgical materials and tools will reduce the present problems such as CSF leak and vascular involvement.

Extent of tumor removal is planned prospectively according to the ABC risk scale (JNS 111: 1053–1061, 2009). Gross total removal is planned for low-risk tumors at or less than 6 score. Two-steps surgery will be beneficial for high-risk tumors. A part of the tumor firmly invaded neurovascular structures or the cavernous sinus are not removed.

Consecutive care for tumor residue is referred with MIB-1. In a case less than 3, simply observed by follow-up MRI twice a year. In a case more than 3, radiosurgery is planned immediately after surgery. For clival chordomas and malignant tumors, proton-beam or carbon-ion radiosurgery will be the first choice for prevention of tumor regrowth.