Tumour Volume and Dose Influence Outcome after Surgery and High-dose Photon Radiotherapy for Chordoma and Chondrosarcoma of the Skull Base and Spine.

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.

A photograph-based study of the incidence of fatal truck underride crashes in Indiana.

Photographs were used to estimate the incidence of fatal crashes in which passenger vehicles underrode the fronts, sides and rears of large trucks in Indiana during 1993. The photographs were obtained for 98 of the 107 eligible fatal crashes between large trucks and passenger vehicles in 1993. A protocol was developed to judge the presence and extent of underride, the presence of intrusion into the passenger vehicle compartment, and the likelihood of death or serious injury if underride had been prevented. The incidence of fatal underride was compared with the incidence reported in the Fatality Analysis Reporting System (FARS), a census of fatal crashes on public roads in the U.S.A. For the same 107 fatal large truck-passenger vehicle crashes, the incidence of underride reported in FARS was much lower than in the photograph-based study: 6 versus 63%. Photographs contain details absent from police reports, the primary data source for FARS, and thus enable more complete identification of underride crashes. Preventing underride would have substantially reduced the likelihood of death or serious injury in ca 20% of the underride crashes.