Chordoma is a rare tumor with difficult to manage. It can appear at any location along axial skeleton. The sacrococcygeal region is the most common site, accounting for 65% of all cases of chordomas, followed by the spheno-occipital/nasal (25%), cervical (10%), and thoracolumbar (5%) spines (14). Because of the slow growing rate and the often nonspecific nature of symptoms, chordoma often appears to be an enlarged mass at the time of presentation (15). Boriani et al. has reported that the slow and gradual onset of pain is the most consistent complaint (16). The time from onset to diagnosis has been reported range from 4–24 months (17). Chordoma is considered as poorly-responsive tumor to conventional radiotherapy and chemotherapy. Thus, surgical resection remains the mainstay of treatment. The oncologic outcomes in term of local control and overall survival are associated with the ability to perform radical resection (18, 19). However, because of the extensive lesion and nearby vascular or neural structures cause margin free En bloc surgery is difficult to perform. Moreover, because the tumor capsule is thin therefore violation of the capsule is sometimes unavoidable and result in contamination of tumor in the operative field and end-up with local recurrent (20).
Although the advancements of surgical techniques have been developed, the consensus on the optimal surgical resection remains unclear. To perform En-Bloc margin free excision, many authors recommend a combined approach (20, 21). However, posterior only approach for En bloc resection of sacral chordoma has been established with favorable outcome (10, 22). In our series, we performed the surgery of sacral chordoma by posterior only approach but in different incision, the longitudinal incision is used in almost cases because of lower risk of wound complication and easy to extended incision proximally if necessary. The transverse incision has a benefit to reach the ilium and sciatic notch without extensive dissection and prefer to use in low sacral resection. The inverted Y incision has the highest risk of wound complication, but this incision has combined the advantage of both longitudinal and transverse incision, this incision is used when the total sacrectomy is planned.
Although local recurrent is common following surgical treatment of spinal chordoma, with reported in the literatures ranging from 19–54% (23). This may be explained by the difference in severity and invasion to nearby structures that preclude the En Bloc resection to be possible. In this series, all patients were referred to our institution, which may be delayed in diagnosis so further enlarged tumor mass with more extensive invasion make it difficult to prevent tumor capsule violation or sometimes impossible for En-Bloc margin free resection. The large size of tumor at presentation and the complexity of sacral structures might partially explain the high rate of local recurrence (24). Furthermore, we prefer to save the sacral roots and bony structure as much as possible to conserve quality of life of patients after the surgery, this may result in recurrent disease due to relatively low response to radiotherapy (25). Result from this study also showed that chordoma is most likely recurrent on the remaining stump, surgical base and adjacent soft tissue such as gluteal muscle comparable with previous studies (4, 16, 18). According to this finding, En-Bloc margin free surgical resection is mandatory to prevent recurrence and surgeons should meticulous seek for local tumor seeding especially when the tumor is rupture. In addition, the anterior approach to free the vascular and vital structures and manage engorged pelvic venous plexus before posterior resection of the sacral tumor should be performed especially in the recurrent large sacral chordoma to prevent excessive bleeding or damage of important structures form scar tissues.
The present study also assessed the surgical outcome of mobile spinal chordoma. The local recurrence after resection of spinal chordoma was not encountered after En Bloc spondylectomy, case No. 9 and 10, but we were not able to prevent distant metastasis (24) (Fig. 6). However, in cervical spine chordoma (case No 8), this study found that recurrence in surrounding soft tissue was encountered. Although the En Bloc surgical resection of the upper cervical spine is not feasible and gross tumor piecemeal resection could provide acceptable long-term survival up to 3 years (26, 27). In this patient the adjuvant radiotherapy was delayed and may lead to rapid local recurrence.
With the high rate of recurrence, intensive follow-up is necessary after initial resection. Daniel et al. proposed the protocol of follow-up chordoma after resection as follows; patients undergo CT scan of the resection bed immediate postoperatively, and MRI scanning is performed within 48 hours. After release from the hospital, surveillance MRI scans are obtained every 3 months in the first year following resection, every 6 months in the second year, and annually thereafter (28). Periodic chest X-Ray and whole body scan have also been purpose in many studies to detect the distance of metastasis (2, 4, 24).
Radiotherapy can be used as an adjuvant treatment for chordoma with incomplete resection or positive margins; however, the relative radioresistance and proximity to sensitive neurologic tissues and other intrapelvic organs make chordoma difficult to treat with standard radiation therapy (8, 29). Conventional photon-beam radiotherapy is commonly used as an adjuvant treatment in patients undergoing subtotal excision. However, reports vary as to whether additional survival benefit is derived. Conventional treatments with doses of 40 to 60 Gy reported 5-year local control rates of 10–40% (29).
To date, proton beam therapy, which makes use of protons or charged particles such as carbon ions, helium, and neon. This technology can deliver high dose radiation to the target tissue that, in principle, could surpass even the most sophisticated photon radiation delivery techniques while minimizing damage to nearby sensitive structures and demonstrated as a promising treatment modality for chordoma (29, 30).
There were some limitations in this study. First, this study was slightly small in number of patients due to the extremely rare disease. Second, because of long-term follow up period, some patients had loss to follow and there were some missing follow-up data. Larger-scale prospective study from multi-center should be conducted to provide more accurate results.
In conclusion, En-bloc free margin resection is mandatory to prevent recurrent of chordoma. Early adjuvant radiotherapy seems to provide benefit if margin free resection is not achieved. The clinical vigilance and investigation to identify tumor recurrent should be obtained periodically, especially, in the first 28 months. Detection of recurrence in early stage with a small mass may be the best chance to perform an En-Bloc margin free resection to prevent further recurrence.