Department of Radiation Oncology, Institut Bergonie, Bordeaux, France.
Institut Gustave Roussy, Villejuif, France.
Int J Radiat Oncol Biol Phys. 2020 Jul 15;107(4):726-735. doi: 10.1016/j.ijrobp.2020.03.041. Epub 2020 Apr 11.
Postoperative radiation therapy (poRT) of intracranial/skull base chondrosarcomas (CHSs) is standard treatment. However, consensus is lacking for poRT in extracranial CHS (eCHS) owing to their easier resectability and intrinsic radioresistance. We assessed the practice and efficacy of poRT in eCHS.
This multicentric retrospective study of the French Sarcoma Group/Rare Cancer Network included patients with eCHS who were operated on between 1985 and 2015. Inverse propensity score weighting (IPTW) was used to minimize poRT allocation biases.
Of 182 patients, 60.4% had bone and 39.6% had soft-tissue eCHS. eCHS were of conventional (31.9%), myxoid (28.6%; 41 extraskeletal, 11 skeletal), mesenchymal (9.9%), or other subtypes. En-bloc surgery with complete resection was performed in 52.6% and poRT in 36.8% of patients (median dose, 54 Gy). Irradiated patients had unfavorable initial characteristics, with higher grade and incomplete resection. Median follow-up time was 61 months. Five-year incidence of local relapse was 10% with poRT versus 21.6% without (P = .050). Using the IPTW method, poRT reduced the local relapse risk (hazard ratio, 0.27; 95% confidence interval, 0.14-0.52; P < .001). Five-year disease-free survival (DFS) was 71.8% with poRT and 64.2% without (P = .680). Using the IPTW method, poRT improved DFS (hazard ratio, 0.51; 95% confidence interval, 0.30-0.85; P = .010). The benefit of poRT on local relapse and DFS was confirmed after exclusion of the extraskeletal subtype. There was no difference in overall survival. Prognostic factors of poorer DFS in multivariate analysis were deeper location, higher grade, incomplete resection, and no poRT.
poRT should be offered in patients with eCHS and high-grade or incomplete resection, regardless of the histologic subtype.
颅内/颅底软骨肉瘤（CHS）术后放疗（poRT）是标准治疗方法。然而，由于颅外 CHS（eCHS）更容易切除且具有内在的放射抵抗性，因此对其进行 poRT 治疗尚未达成共识。我们评估了 eCHS 中 poRT 的应用和疗效。
本研究为法国肉瘤组/罕见癌症网络的多中心回顾性研究，纳入了 1985 年至 2015 年间接受手术治疗的 eCHS 患者。采用逆概率评分加权（IPTW）法以最小化 poRT 分配偏倚。
182 例患者中，60.4%为骨 eCHS，39.6%为软组织 eCHS。eCHS 的组织学亚型包括传统型（31.9%）、黏液样型（28.6%，其中 41 例为骨外，11 例为骨内）、间充质型（9.9%）或其他亚型。52.6%的患者行整块切除术，36.8%的患者行 poRT（中位剂量 54 Gy）。接受放疗的患者初始特征较差，肿瘤分级较高且未完全切除。中位随访时间为 61 个月。接受 poRT 治疗的患者 5 年局部复发率为 10%，未接受 poRT 治疗的患者为 21.6%（P =.050）。采用 IPTW 法，poRT 降低了局部复发风险（风险比，0.27；95%置信区间，0.14-0.52；P <.001）。接受 poRT 治疗的患者 5 年无病生存率（DFS）为 71.8%，未接受 poRT 治疗的患者为 64.2%（P =.680）。采用 IPTW 法，poRT 改善了 DFS（风险比，0.51；95%置信区间，0.30-0.85；P =.010）。排除骨外亚型后，poRT 对局部复发和 DFS 的获益仍得到确认。两组患者的总生存率无差异。多因素分析显示，DFS 较差的预后因素包括肿瘤位置较深、肿瘤分级较高、未完全切除和未行 poRT。
对于 eCHS 患者，无论组织学亚型如何，只要肿瘤分级较高或未完全切除，都应考虑行 poRT 治疗。
