Data as of 29 June 2022
The main treatment for chordoma and chondrosarcoma is surgery followed by radiation which requires high doses of radiation. The local control rates are correlated with patient survival. Patients should be treated in specialized institutions and receive intensity-modulated radiation therapy at a minimum. Particle therapy should be highly considered especially when high doses of radiation are needed for stopping tumor growth and limiting the amount of radiation to the surrounding vital organs.
Particle therapy, such as protons and carbon particles, is considered the standard treatment for irradiating cancer or tumors around the base of the skull. Due to the physical properties of protons and carbon particles, they emit high amounts of radiation to the end of the range in the tissues, or the point where the protons stop moving, called the Bragg peak, after which the amount of radiation decreases rapidly. This is different from high-energy X-rays or photons used in intensity-modulated radiation. Particle irradiation has the following advantages:
- Increasing the dose of radiation to the tumor (dose escalation to the tumor) when needed
- The radiation at the tumor’s front and back are quite tiny. This reduces the likelihood of radiation side effects. If there is a recurrence, the doctor will find it easier to re-irradiate the same location if the radiation dose to the surrounding organs was minimal during the initial irradiation.
- In comparison to previous studies that only used photon radiation, more recent studies demonstrate an increase in disease control and better oncologic outcomes. Under particle therapy alone or combined proton/photon irradiation, the specific disease control rate and 5-year survival rate were 80-90%.
Numerous retrospective studies have shown that the treatment outcomes of skull base chordoma and chondrosarcoma can be improved with particle therapy when compared to photon radiation. This resulted in the development of a prospective, non-comparative phase 2 trial in patients by MD Anderson Cancer Center, USA, which presented the preliminary data at the 2019 American Society of Radiation Oncology Annual Meeting. The local control rate at 5 years was 89% in chordomas and 100% in chondrosarcomas with acceptable radiation-related toxicities.
