A prospective single arm phase II study of dacarbazine and treosulfan as first-line therapy in metastatic uveal melanoma.

Uveal melanoma is relatively uncommon accounting for fewer than 5% of all melanoma cases. Localized tumours are curable by local therapy but a significant percentage of patients go on to have a relapse with metastatic disease. Uncertainty remains concerning the level of activity of dacarbazine in uveal melanoma as opposed to that in the cutaneous form. Recently, a possible role for treosulfan in uveal disease has been reported. A phase II study was therefore undertaken to assess the objective response rate of the combination of dacarbazine and treosulfan in previously untreated patients with metastatic uveal melanoma. All patients received dacarbazine 850 mg/m and treosulfan 8 g/m(2) every 21 days up to a maximum of six cycles. Fifteen patients enrolled in the study. As expected, the major toxicities were haematological (particularly thrombocytopaenia) but the treatment was generally well tolerated. No responses were seen; however, disease stabilization was achieved in two patients. Median progression free survival from the start of chemotherapy was 12 weeks and median overall survival was 30 weeks. This study, using the combination of dacarbazine and treosulfan, while well tolerated, did not confirm earlier reports suggesting treosulfan is active in uveal melanoma.

Influence of dose calculation algorithms on isotoxic dose-escalation of non-small cell lung cancer radiotherapy.

BACKGROUND AND PURPOSE: A series of phase I/II clinical trials are being initiated in several UK centres to explore the use of dose-escalated schedules for the treatment of non-small cell lung cancer (NSCLC). Among them the IDEAL-CRT trial (ISRCTN12155469) will investigate the introduction of individualised "isotoxic" treatment schedules based on the relative mean lung normalised total dose (rNTD(mean)), an estimator related to lung toxicity. Since treatment planning will be performed using different treatment planning systems (TPSs), for the quality assurance of the trial we have carried out work to quantify the influence of dose calculation algorithms based on the determination of rNTD(mean) and on the choice of individualised prescription doses. MATERIAL AND METHODS: Twenty-five patient plans with stage I, II and III NSCLC were calculated, with the same prescription dose, using the Adaptive Convolve (AC) and Collapsed Cone (CC) algorithms of the Pinnacle TPS, the pencil beam convolution (PBC) and AAA algorithms of Eclipse, and the CC and pencil beam (PB) algorithms of Oncentra Masterplan (OMP). For the paired-lungs-GTV structure, dose-volume histograms were obtained and used to calculate the corresponding rNTD(mean) values and results obtained with the different algorithms were compared. RESULTS: For most (19 out of 25) of the patients studied, no algorithm-to-algorithm differences were seen in dose prescription based on rNTD(mean). For the other 6 patients differences were within 2.3 Gy, except in one case where the difference was 4 Gy. CONCLUSIONS: For the IDEAL-CRT trial no corrections need to be applied to the value of rNTD(mean) calculated using any of the more advanced convolution/superposition algorithms studied in this work. For the two pencil beam algorithms analysed, no correction is necessary for the data obtained with the Eclipse-PBC, while for OMP-PB data a small correction needs to be applied, by using a scaling factor, to make prescription doses consistent with the other algorithms investigated.