[18]F-fluoroethyl-l-tyrosine positron emission tomography for radiotherapy target delineation: Results from a Radiation Oncology credentialing program.

Background and purpose: The [18]F-fluoroethyl-l-tyrosine (FET) PET in Glioblastoma (FIG) study is an Australian prospective, multi-centre trial evaluating FET PET for newly diagnosed glioblastoma management. The Radiation Oncology credentialing program aimed to assess the feasibility in Radiation Oncologist (RO) derivation of standard-of-care target volumes (TVMR) and hybrid target volumes (TVMR+FET) incorporating pre-defined FET PET biological tumour volumes (BTVs). Materials and methods: Central review and analysis of TVMR and TVMR+FET was undertaken across three benchmarking cases. BTVs were pre-defined by a sole nuclear medicine expert. Intraclass correlation coefficient (ICC) confidence intervals (CIs) evaluated volume agreement. RO contour spatial and boundary agreement were evaluated (Dice similarity coefficient [DSC], Jaccard index [JAC], overlap volume [OV], Hausdorff distance [HD] and mean absolute surface distance [MASD]). Dose plan generation (one case per site) was assessed. Results: Data from 19 ROs across 10 trial sites (54 initial submissions, 8 resubmissions requested, 4 conditional passes) was assessed with an initial pass rate of 77.8 %; all resubmissions passed. TVMR+FET were significantly larger than TVMR (p < 0.001) for all cases. RO gross tumour volume (GTV) agreement was moderate-to-excellent for GTVMR (ICC = 0.910; 95 % CI, 0.708-0.997) and good-to-excellent for GTVMR+FET (ICC = 0.965; 95 % CI, 0.871-0.999). GTVMR+FET showed greater spatial overlap and boundary agreement compared to GTVMR. For the clinical target volume (CTV), CTVMR+FET showed lower average boundary agreement versus CTVMR (MASD: 1.73 mm vs. 1.61 mm, p = 0.042). All sites passed the planning exercise. Conclusions: The credentialing program demonstrated feasibility in successful credentialing of 19 ROs across 10 sites, increasing national expertise in TVMR+FET delineation.

A single-institution prospective evaluation of a neuro-oncology multidisciplinary team meeting.

Multi-disciplinary team meetings (MDTs) are considered essential to quality cancer care. For some malignancies, MDTs have been associated with improved outcomes, but data regarding the neuro-oncology MDT is limited. We prospectively described the MDT at our institution and evaluated its impact on clinical management. Cases were discussed amongst the treating team and a pre-MDT plan and reason for discussion (RFD) was documented before the MDT. Patient specific clinical data was captured prospectively, with further pathological and radiological information captured during the MDT. Subsequently, the MDT consensus decision was recorded. High impact decisions (HID) were those in which the pre-MDT plan was substantially modified. A HID rate of >10% was considered clinically significant. Adherence to MDT recommendations was recorded. Seventy-nine cases were discussed at the MDT. Fifty-two cases (66%) were male. The median age was 53 (17-84). Thirty-three cases were new diagnoses and the remainder were relapsed/progressive disease. Thirty-nine cases were primary brain tumours, 25 were metastatic tumours and 15 were other. Twenty-eight (35%) had HID. No RFDs were statistically significantly associated with a HID (p = 0.265). Adherence data was collected for 95% (75) of cases. Treatment concordance with the MDT plan occurred in 90% (67) of cases. For cases of non-concordance, six out of eight (75%) were due to patient choice. Overall, a clinically significant proportion of treatment modifications are made at the neuro-oncology MDT. There were no case types which did not benefit from MDT discussion. MDT recommendations were largely adhered to, and in cases of non-concordance, were largely due to patient choice.