Variations in target volume definition and dose to normal tissue using anatomic versus biological imaging (18 F-FDG-PET) in the treatment of bone metastases: results from a 3-arm randomized phase II trial

PSMA-PET/CT-Based Stereotactic Body Radiotherapy (SBRT) in the Treatment of Uncomplicated Non-Spinal Bone Oligometastases from Prostate Cancer

BACKGROUND AND PURPOSE

Stereotactic body radiotherapy (SBRT) has a consolidated role in the treatment of bone oligometastases from prostate cancer (PCa). While the evidence for spinal oligometastases SBRT was robust, its role in non-spinal-bone metastases (NSBM) is not standardized. In fact, there was no clear consensus about dose and target definition in this setting. The aim of our study was to evaluate efficacy, toxicity, and the pattern of relapse in SBRT delivered to NSBM from PCa.

MATERIALS AND METHODS

From 2016 to 2021, we treated a series of oligo-NSBM from PCa with ⁶⁸Ga-PSMA PET/CT-guided SBRT. The primary endpoint was local progression-free survival (LPFS). The secondary endpoints were toxicity, the pattern of intraosseous relapse, distant progression-free survival (DPFS), polimetastases-free survival (PMFS), and overall survival (OS).

RESULTS

a total of 150 NSBM in 95 patients were treated with 30-35 Gy in five fractions. With a median follow-up of 26 months, 1- and 3 years LPFS was 96.3% and 89%, respectively. A biologically effective dose (BED) ≥ 198 Gy was correlated with improved LPFS (p = 0.007). Intraosseous relapse occurred in eight (5.3%) cases. Oligorecurrent disease was associated with a better PMFS compared to de novo oligometastatic disease (p = 0.001) and oligoprogressive patients (p = 0.007). No grade ≥ 3 toxicity occurred.

CONCLUSION

SBRT is a safe and effective tool for NSBM from PCa in the oligometastatic setting. Intraosseous relapse was a relatively rare event. Predictive factors of the improved outcomes were defined.

Interobserver variation in clinical target volume (CTV) delineation for stereotactic radiotherapy to non-spinal bone metastases in prostate cancer: CT, MRI and PET/CT fusion

BACKGROUND AND PURPOSE

The use of SBRT for the treatment of oligometastatic prostate cancer is increasing rapidly. While consensus guidelines are available for non-spinal bone metastases practice continues to vary widely. The aim of this study is to look at inter-observer variability in the contouring of prostate cancer non-spinal bone metastases with different imaging modalities.

MATERIALS AND METHODS

15 metastases from 13 patients treated at our centre were selected. 4 observers independently contoured clinical target volumes (CTV) on planning CT alone, planning CT with MRI fusion, planning CT with PET-CT fusion and planning CT with both MRI and PET-CT fusion combined. The mean inter-observer agreement on each modality was compared by measuring the delineated volume, generalized conformity index (CIgen), and the distance of the centre of mass (dCOM), calculated per metastasis and imaging modality.

RESULTS

Mean CTV volume delineated on planning CT with MRI and PET-CT fusion combined was significantly larger compared to other imaging modalities (p = 0.0001). CIgen showed marked variation between modalities with the highest agreement between planning CT + PET-CT (mean CIgen 0.55, range 0.32-0.73) and planning CT + MRI + PET-CT (mean CIgen 0.59, range 0.34-0.73). dCOM showed small variations between imaging modalities but a significantly shorter distance found on planning CT + PET-CT when compared with planning CT + PET-CT + MRI combined (p = 0.03).

CONCLUSIONS

Highest consistency in CTV delineation between observers was seen with planning CT + PET-CT and planning CT + PET-CT + MRI combined.

Are the MORECare guidelines on reporting of attrition in palliative care research populations appropriate? A systematic review and meta-analysis of randomised controlled trials

BACKGROUND

Palliative care trials have higher rates of attrition. The MORECare guidance recommends applying classifications of attrition to report attrition to help interpret trial results. The guidance separates attrition into three categories: attrition due to death, illness or at random. The aim of our study is to apply the MORECare classifications on reported attrition rates in trials.

METHODS

A systematic review was conducted and attrition classifications retrospectively applied. Four databases, EMBASE; Medline, CINHAL and PsychINFO, were searched for randomised controlled trials of palliative care populations from 01.01.2010 to 08.10.2016. This systematic review is part of a larger review looking at recruitment to randomised controlled trials in palliative care, from January 1990 to early October 2016. We ran random-effect models with and without moderators and descriptive statistics to calculate rates of missing data.

RESULTS

One hundred nineteen trials showed a total attrition of 29% (95% CI 28 to 30%). We applied the MORECare classifications of attrition to the 91 papers that contained sufficient information. The main reason for attrition was attrition due to death with a weighted mean of 31.6% (SD 27.4) of attrition cases. Attrition due to illness was cited as the reason for 17.6% (SD 24.5) of participants. In 50.8% (SD 26.5) of cases, the attrition was at random. We did not observe significant differences in missing data between total attrition in non-cancer patients (26%; 95% CI 18-34%) and cancer patients (24%; 95% CI 20-29%). There was significantly more missing data in outpatients (29%; 95% CI 22-36%) than inpatients (16%; 95% CI 10-23%). We noted increased attrition in trials with longer durations.

CONCLUSION

Reporting the cause of attrition is useful in helping to understand trial results. Prospective reporting using the MORECare classifications should improve our understanding of future trials.