An accurate method to quantify breathing-induced prostate motion for patients implanted with electromagnetic transponders

Purpose: To validate and apply a method for the quantification of breathing-induced prostate motion (BIPM) for patients treated with radiotherapy and implanted with electromagnetic transponders for prostate localization and tracking. Methods: For the analysis of electromagnetic transponder signal, dedicated software was developed and validated with a programmable breathing simulator phantom. The software was then applied to 1,132 radiotherapy fractions of 30 patients treated in supine position, and to a further 61 fractions of 2 patients treated in prone position. Results: Application of the software in phantom demonstrated reliability of the developed method in determining simulated breathing frequencies and amplitudes. For supine patients, the in vivo analysis of BIPM resulted in median (maximum) amplitudes of 0.10 mm (0.35 mm), 0.24 mm (0.66 mm), and 0.17 mm (0.61 mm) in the left-right (LR), cranio-caudal (CC), and anterior-posterior (AP) directions, respectively. Breathing frequency ranged between 7.73 and 29.43 breaths per minute. For prone patients, the ranges of the BIPM amplitudes were 0.1-0.5 mm, 0.5-1.3 mm, and 0.7-1.7 mm in the LR, CC, and AP directions, respectively. Conclusions: The developed method was able to detect the BIPM with sub-millimeter accuracy. While for patients treated in supine position the BIPM represents a reduced source of treatment uncertainty, for patients treated in prone position, it can be higher than 3 mm

ASSOCIATION BETWEEN PHYSICAL ACTIVITY AND QUALITY OF LIFE IN PROSTATE CANCER PATIENTS FOLLOWING ACTIVE SURVEILLANCE

Introduction Active surveillance (AS) can be an attractive and feasible management option for patients with low-grade, low-volume prostate cancer (PCa) (Dall’Era et al., 2008). It is still unclear if living with an untreated cancer can lower the quality of life (QoL) of these patients (Daubenmier et al., 2006). Few studies investigated those aspects and explored the factors that are able to hinder or improve the QoL in these patients (Bellardita et al., 2014). In particular, there is a paucity of studies investigating the potential of health-promoting behaviors, such as engaging in greater physical exercise, in improving QoL and wellbeing of men with PCa in AS (Daubenmier et al., 2006). The purpose of the present study was to investigate the association between physical activity and QoL in patients with PCa in AS. Methods Pca patients enrolled in the Prostate cancer Research International: AS (PRIAS) protocol and accepting to participate in an ancillary study on QoL were invited to participate. At 10 month after the diagnosis, patients were asked to complete self-reported validated questionnaires assessing physical activity (through the International Physical Activity Questionnaire - IPAQ) and generic and disease-specific health-related QoL (through the Short Form 36 - SF-36 – and the Functional Assessment of Cancer Therapy scale Prostate Version - FACT-P). Descriptive analyses were conducted and stepwise multiple regression analyses were performed to examine the impact of exercise type and activity on QoL scores. Statistical significance was established at p < .05. Results 81 patients with a mean age of 64 years (SD=7; 42-79 years) accepted to participate. Analyses showed that patients engaging in more physical activity experience greater physical wellbeing (FACT-P) (p=0.018; R2=0.085; F=5.294; ß=0.291) and higher mental health scores (SF-36) (p=0.025; R2=0.071; F=5.268; ß=0.266). In particular, patients doing greater vigorous activity reported greater FACT-P functional wellbeing (p=0.025; R2=0.08; F=5.253; ß =0.273). Conclusion The present study indicated that almost the 10% of variance of physical, mental, and functional QoL of Pca men in AS can be explained by changes in physical exercise. Our results, although preliminary and limited by small sample and effect size, highlight the importance to recommend lifestyle change in AS clinical practice and to focus upon strategies to support maintenance of exercise activity to sustain QoL of Pca patients in AS