Tumour Volume and Dose Influence Outcome after Surgery and High-dose Photon Radiotherapy for Chordoma and Chondrosarcoma of the Skull Base and Spine. Issue 4 (April 2018)

• Record Type: Journal Article
• Authors: Gatfield, E.R.; Noble, D.J.; Barnett, G.C.; Early, N.Y.; Hoole, A.C.F.; Kirkby, N.F.; Jefferies, S.J.; Burnet, N.G.
• Is Part Of: Clinical oncology. Volume 30:Issue 4(2018)
• Page Start: 243
• Page End: 253
• Publication Date: 2018-04
• Subjects: Chondrosarcoma -- chordoma -- local control -- radiotherapy -- tumour volume; Oncology -- Periodicals; Tumors -- Periodicals; Cancer -- Treatment -- Periodicals; Radiotherapy -- Periodicals; Neoplasms -- Periodicals; Cancer -- Radiotherapy; Cancer -- Treatment; Oncology; Medical radiology; Radiotherapy; Tumors; Electronic journals; Periodicals; 616.994
• DOI: 10.1016/j.clon.2018.01.002
• Languages: English
• ISSNs: 0936-6555

Abstract

Abstract: Aims: To evaluate the long-term outcomes of patients with chordoma and low-grade chondrosarcoma after surgery and high-dose radiotherapy. Materials and methods: High-dose photon radiotherapy was delivered to 28 patients at the Neuro-oncology Unit at Addenbrooke's Hospital (Cambridge, UK) between 1996 and 2016. Twenty-four patients were treated with curative intent, 17 with chordoma, seven with low-grade chondrosarcoma, with a median dose of 65 Gy (range 65–70 Gy). Local control and survival rates were calculated using the Kaplan–Meier method. Results: The median follow-up was 83 months (range 7–205 months). The 5 year disease-specific survival for chordoma patients treated with radical intent was 85%; the local control rate was 74%. The 5 year disease-specific survival for chondrosarcoma patients treated with radical intent was 100%; the local control rate was 83%. The mean planning target volume (PTV) was 274.6 ml (median 124.7 ml). A PTV of 110 ml or less was a good predictor of local control, with 100% sensitivity and 63% specificity. For patients treated with radical intent, this threshold of 110 ml or less for the PTV revealed a statistically significant difference when comparing local control with disease recurrence ( P = 0.019, Fisher's exact test). Our data also suggest that the probability of disease control may be partly related to both target volume and radiotherapy dose. Conclusion: Our results show that refined high-dose photon radiotherapy, following tumour resection by a specialist surgical team, is effective in the long-term control of chordoma and low-grade chondrosarcoma, even in the presence of metal reconstruction. The results presented here will provide a useful source for comparison between high-dose photon therapy and proton beam therapy in a UK setting, in order to establish best practice for the management of chordoma and low-grade chondrosarcoma. Highlights: Long-term study of chordoma and chondrosarcoma patients after photon radiotherapy. Five year local control rates were 74% for chordoma and 83% for chondrosarcoma. PTV of 110 ml or less was a statistically significant predictor of disease control. Local control probability related to product of target volume and radiotherapy dose. Source for comparison between photon and proton beam therapies in a UK setting.