Chordoma

Epidemiology
300 cases/year in US
More common in males
Rare in patients under 40

Pathology
Cell of origin is a remnant of the primitive notochord
Not to be confused with CHONDROMA (benign cartilaginous tumor) or CHONDROSARCOMA
Slow growing but invasive with ~25% pts developing mets

Clinical
Axial skeleton: 1/3 are cranial, usually clival; 1/2 sacrum and coccyx

Headache
Cranial nerve palsy
Bony destruction

Prognostic factors: extent of resection, +/- brainstem involvement

Therapy
Surgery recommended but usually subtotal
Adjuvant RT for residual disease, unresectable tumors
Dose is limited by neural structures; protons have been successful in dose escalation

Disease control with RT

	Chondrosarcoma	Chordoma
Photons (50-66Gy)
5Y-RFS	~90%	50-65%
5Y-OS	50 - 80%	40 - 60%
Protons (66 - 79 CGE)
5Y-RFS	~90%	60 - 75%
5Y-OS	~100%	80%