Holtzman et al., reviewed the medical records of 43 patients with a median age of 49 years (range, 23-80 years) treated with double-scattered 3D conformal proton therapy for skull-base chondrosarcomas between January 2007 and February 2016. Proton therapy-related toxicities were scored using CTCAE v4.0.
The median radiotherapy dose was 73.8 Gy(RBE) (range, 64.5-74.4 Gy[RBE]). Thirty-six (84%) and 7 (16%) patients underwent surgical resection or biopsy alone. Tumor grade distribution included: grade 1, 19 (44%) patients; grade 2, 22 (51%); and grade 3, 2 (5%). Forty patients had gross disease at the time of radiotherapy and 7 patients were treated for locally recurrent disease following surgery. The median follow-up was 3.7 years (range, 0.7-10.1 years). There were no acute grade 3 toxicities related to RT. At 4 years following RT, actuarial rates of overall survival, cause-specific survival, local control, and RT-related grade 3 toxicity-free survival were 95%, 100%, 89%, and 95%.
High-dose, double-scattered 3D conformal proton therapy alone or following surgical resection for skull-base chondrosarcoma is an effective treatment with a high rate of local control with no acute grade 3 radiation-related toxicity. Further follow-up of this cohort is necessary to better characterize long-term disease control and late toxicities 1).
The potential malignant progression of enchondroma into a secondary chondrosarcoma is a well-known fact. Nevertheless, chondrosarcoma located at the skull base in patients with Maffuci syndrome is a very rare condition, with only 18 cases reported in the literature.
Beer-Furlan et al. report 2 other cases successfully treated through an expanded endoscopic endonasal approach and discuss the condition based on the literature review.
Skull base chondrosarcoma associated with Maffucci syndrome is a rare condition. The disease cannot be cured, therefore surgical treatment should be performed in symptomatic patients aiming for maximal tumor resection with function preservation. The endoscopic endonasal approach is a safe and reliable alternative for the management of these tumors 2).