Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, 6229 HX Maastricht, The Netherlands.
Department of Radiology, King Fahad Hospital of Imam Abdulrahman Bin Faisal University, Al Khobar 34212, Saudi Arabia.
Curr Oncol. 2022 Mar 28;29(4):2364-2375. doi: 10.3390/curroncol29040191.
Chordoma are rare tumors of the axial skeleton. The treatment gold standard is surgery, followed by particle radiotherapy. Total resection is usually not achievable in skull base chordoma (SBC) and high recurrence rates are reported. Ectopic recurrence as a first sign of treatment failure is considered rare. Favorable sites of these ectopic recurrences remain unknown.
Five out of 16 SBC patients treated with proton therapy and surgical resection developed ectopic recurrence as a first sign of treatment failure were critically analyzed regarding prior surgery, radiotherapy, and recurrences at follow-up imaging.
Eighteen recurrences were defined in five patients. A total of 31 surgeries were performed for primary tumors and recurrences. Seventeen out of eighteen (94%) ectopic recurrences could be related to prior surgical tracts, outside the therapeutic radiation dose. Follow-up imaging showed that tumor recurrence was difficult to distinguish from radiation necrosis and anatomical changes due to surgery.
In our cohort, we found uncommon ectopic recurrences in the surgical tract. Our theory is that these recurrences are due to microscopic tumor spill during surgery. These cells did not receive a therapeutic radiation dose. Advances in surgical possibilities and adjusted radiotherapy target volumes might improve local control and survival.
软骨肉瘤是一种罕见的轴性骨骼肿瘤。治疗的金标准是手术，然后进行粒子放疗。颅底软骨肉瘤（SBC）通常无法完全切除，且报道的复发率较高。作为治疗失败的第一个迹象的异位复发被认为很少见。这些异位复发的有利部位尚不清楚。
在接受质子治疗和手术切除的 16 名 SBC 患者中，有 5 名患者出现了作为治疗失败的第一个迹象的异位复发，对这些患者的先前手术、放疗以及随访影像学上的复发情况进行了严格分析。
在 5 名患者中确定了 18 个复发灶。总共对原发性肿瘤和复发病灶进行了 31 次手术。18 个（94%）异位复发中的 17 个可以追溯到手术路径，且超出了治疗辐射剂量。随访影像学显示，由于手术导致的肿瘤复发与放射性坏死和解剖结构变化难以区分。
在我们的队列中，我们发现了手术路径中罕见的异位复发。我们的理论是，这些复发是由于手术过程中肿瘤细胞的微小播散所致。这些细胞未接受治疗性辐射剂量。手术可能性的进步和调整放疗靶区可能会改善局部控制和生存率。
