Chordomas, with locally aggressive behavior and poor prognosis, are thought to arise from embryo notochordal remnants of the neuraxis, predominantly in the skull base, vertebral column, and sacrococcygeal area.[12,21] No wonder that clinical management of chordoma is usually challenging for its locally invasive growth pattern. Using the patient data from the SEER database, we constructed a nomogram that indicated survival was associated with many factors. The C-index and the graphical calibration method suggested that nomogram exhibited a good predictive ability.
Univariate analysis revealed that year of diagnosis was a predictor of survival, but further multivariate analysis was not further performed as different follow-up time was a point.
Our result showed that age group (20-39 years) was a favorable factor for both CSS and OS in the patients with spinal cord tumor. Younger age, with a tendency to aggressive clinical behavior, has been described as an adverse factor for poor survival, which is consistent with our finding, on multivariate analysis, that patients under 20 had a worse survival.[5,21]
The histological variants are classified into 3 groups: classical (conventional), chondroid, and dedifferentiated. While patients diagnosed with chordoma NOS have better outcome, those in a mix group with chondroid chordoma and dedifferentiated chordoma had a poor survival in our study.
This current study demonstrated that surgery played an important role in the treatment of patients of chordomas. Also, this outcome added support to previous literature suggesting a better survival related to aggressive treatment.[24,15,11,25,1]
Extent of resection was the most important factor in prediction survival, with only 75.9% (cranial group) and 75.3% (spinal cord group) actuarial 10 year CSS rate for GTR, with 71.8% (cranial group) and 65.1% (spinal cord group) actuarial 10-year CSS rate for non-GTR. One retrospective study, with 31 pediatric chordomas, showed 90% survival in 10 patients with GTR, compared with only 29% OS rate at 10 years after subtotal resection. but, in terms of a high risk commonly seen in the skull base and local invasion of tumor, GTR might be not possible and neurological preservation should be took notice of.
Interestingly, the addition of radiotherapy showed the significantly poor CSS in patients with spinal cord chordoma. Recently, Lee et al and Jawad, using the data from the SEER database, showed similar results that adjuvant radiation was associated with worse survival outcomes.[14,13] These results seemed to contributed to the relation between the use of radiotherapy and disappointing survival. Indeed, radiotherapy alone, in a large number of people, led to a poor prognosis, to some degree, which caused an unbelievable finding that surgery with radiation was related to worse survival compared with surgery alone. Moreover, there was no identified treatment dose or objective quality assessment in this retrospective study. Radiotherapy was traditionally recommended in the form of hypofractionated proton beam or photo beam with at least 74 Gy for patients with chordoma. Y et al. described a series of 282 patients with sacral and spinal chordoma, but significantly increased OS was not observed in patients who underwent radiation with a median dose of 58 Gy; while Schuli-Ertner reported that radiation dose more than 60 CGE was a favorable factor for local control; these results suggested high dose radiation could improve survival. In addition, radiation sequence might be a key factor of survival: preoperative radiation+surgery+radiotherapy vs. surgery+radiotherapy.[26,18] Last, patients with poor condition (regional or distant metastasis) were more likely to receive radiation. Maybe that the extension of this tumor counteracted the role the radiation in survival.
In particular, there was a paucity of studies regarding the association between chemotherapy and survival. The routine use of chemotherapy in addition to surgery is controversial because although pervious report advocated that chemotherapy could increase survival, others suspected this finding.[4,22]
In this current study, no difference in survival was observed between surgery alone and surgery with chemotherapy for cranial chordoma; to our surprise, patients with surgery and chemotherapy had a worse survival compared with those with surgery alone for spinal cord chordoma. It is important to realize that the rate of radiotherapy receipt was pretty low, in 2.4% of patients with cranial chordoma and in 5.2 of patients with spinal cord chordoma, respectively.
Considering its malignancy[3,6], with local recurrence and distant metastasis, it is imperative to need evidence from a randomized trial supporting the addition of chemotherapy.