Mid-term follow-up surgical results in 284 cases of clival chordomas: the risk factors for outcome and tumor recurrence

Abstract

Objective Skull base chordoma (SBC) is rare and one of the most challenging diseases to treat. We aimed to assess the optimal timing of adjuvant radiation therapy (RT) and to evaluate the factors that influence resection and long-term outcomes. Methods In total, 284 patients with 382 surgeries were enrolled in this retrospective study. Postsurgically, 64 patients underwent RT before recurrence (pre-recurrence RT), and 47 patients underwent RT after recurrence. During the first attempt to achieve gross-total resection (GTR), when the entire tumor was resected, 268 patients were treated with an endoscopic midline approach, and 16 patients were treated with microscopic lateral approaches. Factors associated with the success of GTR were identified using χ2 and logistic regression analyses. Risk factors associated with chordoma-specific survival (CSS) and progression-free survival (PFS) were evaluated with the Cox proportional hazards model. Results In total, 74.6% of tumors were marginally resected [GTR (40.1%), near-total resection (34.5%)]. History of surgery, large tumor volumes, and tumor locations in the lower clivus were associated with a lower GTR rate. The mean follow-up period was 43.9 months. At the last follow-up, 181 (63.7%) patients were alive. RT history, histologic subtype (dedifferentiated and sarcomatoid), non-GTR, no postsurgical RT, and the presence of metastasis were associated with poorer CSS. Patients with pre-recurrence RT had the longest PFS and CSS, while patients without postsurgical RT had the worst outcome. Conclusion GTR is the goal of initial surgical treatment. Pre-recurrence RT would improve outcome regardless of GTR.

Intraoperative Magnetic Resonance Imaging Assisted Endoscopic Endonasal Resection of Clival Chordomas

“…Total tumor resection has been shown to be the most important factor in progression-free survival and overall survival in skull base chordomas (4)(5)(6)(7)(8)16). Controversy over aggressive tumor resection in skull base chordomas arises from the tumor's relationship to critical neurovascular structures and that total resection often results in significant morbidity (2,7,8). Tumor diameter and aggressive growth pattern, previous surgery and radiation therapy have been found to be associated with postoperative morbidity rates (7,8,17,18).…”

“…Controversy over aggressive tumor resection in skull base chordomas arises from the tumor's relationship to critical neurovascular structures and that total resection often results in significant morbidity (2,7,8). Tumor diameter and aggressive growth pattern, previous surgery and radiation therapy have been found to be associated with postoperative morbidity rates (7,8,17,18). Although modern skull base techniques implemented in experienced centers have reduced the mortality and morbidity associated with chordoma resection, chordomas are considered to be tumors that cannot be curable surgically (2,(4)(5)(6)17).…”

“…There are various arguments regarding the optimal therapy for skull base chordomas (5)(6)(7). In most cases, maximal resection followed by adjuvant radiation therapy for the residual or recurrent tumor is recommended (5,6,8).…”

“…Also, some studies showed that some tumor biological features, such as histological factors, Ki 67 labeling index, chromosomal abnormalities may affect survival (10,11). Chordomas show varying degrees of radioresistance and a tendency to recurrence, so total tumor resection prolongs progression-free survival (1,(4)(5)(6)(7)(8)10).…”

“…In most cases, maximal resection followed by adjuvant radiation therapy for the residual or recurrent tumor is recommended ( 5 , 6 , 8 ). However, due to the rarity of the disease, a standard treatment guideline has not been established yet ( 4 , 5 , 7 , 9 ). Also, some studies showed that some tumor biological features, such as histological factors, Ki 67 labeling index, chromosomal abnormalities may affect survival ( 10 , 11 ).…”