Cranial Chordoma: A New Preoperative Grading System

Abstract

BACKGROUNDChordomas are rare but challenging neoplasms involving the skull base. A preoperative grading system will be useful to identify both areas for treatment and risk factors, and correlate to the degree of resection, complications, and recurrence.OBJECTIVETo propose a new grading system for cranial chordomas designed by the senior author. Its purpose is to enable comparison of different tumors with a similar pathology to clivus chordoma, and statistically correlate with postoperative outcomes.METHODSThe numerical grading system included tumor size, site of the tumor, vascular encasement, intradural extension, brainstem invasion, and recurrence of the tumor either after surgery or radiotherapy with a range of 2 to 25 points; it was used in 42 patients with cranial chordoma. The grading system was correlated with number of operations for resection, degree of resection, number and type of complications, recurrence, and survival.RESULTSWe found 3 groups: low-risk 0 to 7 points, intermediate-risk 8 to 12 points, and high-risk ≥13 points in the grading system. The 3 groups were correlated with the following: extent of resection (partial, subtotal, or complete; P < .002); number of operative stages to achieve removal (P < .014); tumor recurrence (P = .03); postoperative Karnofsky Performance Status (P < .001); and with successful outcome (P = .005). The grading system itself correlated with the outcome (P = .005).CONCLUSIONThe proposed chordoma grading system can help surgeons to predict the difficulty of the case and know which areas of the skull base will need attention to plan further therapy.

Apparent diffusion coefficient as a prognostic factor in clival chordoma

“…Clival chordoma is a rare, primary bone tumor arising from notochord remnants 17 , 18 . It can infiltrate various areas of the skull base such as the upper, middle and lower clivus, cavernous sinus, petrous bone, and upper cervical spine with or without intradural invasion 13 . Complete surgical resection is a challenge considering the deep-seated location of the tumor and the close proximity to critical neurovascular structures.…”

“…Many studies have investigated prognostic factors of clival chordoma, but the understanding of the disease is still limited due to its rarity and cancer biology. Previous studies have revealed that tumor size, location, and extent of resection (EOR) are associated with overall survival (OS) and progression-free survival (PFS) in clival chordoma 4 , 13 , 14 . However, there are still no reliable factors that could predict the behavior of the tumor before treatment begins.…”

Long Follow-up Surgical Results in 284 Cases of Clival Chordomas: The Risk Factors for Outcome and Tumor Recurrence

“…CSF leakage and cranial nerve injury were the main complications in prior studies [17,14,6]. Bene ting mainly from the application of vascularized nasoseptal aps [17,7], CSF leakage was low in our group (3.9%).…”

“…This may be explained by our previous nding that most children with SBCs had these tumors in the lower clivus and cranio-cervical junction area [4]. Tumors in the lower clivus have the lowest GTR rate [14,17,6,4]. Not surprisingly, history of surgery, large tumor volume and tumor location are independent risk factors for GTR, as supported by previous studies [30,14,17,26,7].…”

“…We emphasize the importance of cleaning tumors that are attached to the dura and maintaining the integrity of the dura, which effectively prevent CSF leakage. Radical resection of all involved dura might account for high rates of CSF leakage (14%) [6,8]. We deem the dura to be a natural barrier against tumor growth intracranially, which has been supported indirectly by two autopsy studies [28,21].…”