Impact of treatment and clinical factors on worsening of functional scales after prostate cancer RT

Abstract

Purpose or Objective The study aimed to evaluate the deterioration of functional outcomes in localized prostate cancer (PCa) patients (pts) treated with external beam radiotherapy (RT) with a focus on oncological treatment and patient features. Materials and Methods EORTC QLQ-C30 (version 3.0) was administered to pts enrolled in a multicenter prospective observational study. For this analysis, we specifically considered one symptom scale (Fatigue) and three functional scales (Physical, Role, Social) at three time-points: baseline, RT end and 2-year after RT. The average score variation in acute and late phases as stratified by treatment and patient factors was determined. We used radar plots to report results quantitatively, and we computed the hexagonal areas from these plots to obtain a summary variable describing the functional status. Worsening in at least 2 (wrs2) or 3 (wrs3) scales were considered as additional endpoints, with cut-offs for clinically significant deterioration defined as suggested by Cooks et al. (EJC 2012). Results A total of 1143 pts with complete information were available. Among treatment features, we considered: prostatectomy, pelvic irradiation (LN), hormone-therapy and fractionation (2-2.65 Gy/fr vs 2.7-3.4 Gy/fr). We explored age, diabetes and urinary symptoms at baseline as patient characteristics. Figure 1 shows a panel of radar plots with scores for the different scales. Table 1 reports hexagonal areas and the prevalence of wrs2/wrs3 as a function of investigated characteristics and time-points. The Ratio of the hexagonal regions “(at RT end)/(at 2-year)” is reported as an index for the recovery of acute effects. Diabetes slows down the impact of RT on functional and symptom scales with a continuous deterioration at 2- year (Ratio=0.85), which is characterized by the best incidence of wrs2 and 3 post-RT and worst incidences in the late phase. Moderate hypofractionation strongly affects the acute phase (Area, wrs2 and 3 incidences), showing at the same time the best recovery index at 2-year. Age does not affect the acute phase but takes part in the recovery capability. Patients who underwent prostatectomy are no more affected by the treatment, probably, because of the long lapse of time between surgery and RT (average time 2.7 year). Small differences are found between patients irradiated or not to LN. As a potential explanation we could mention the difference in the average dose/fraction for patients with and without LN irradiation, 2.00 Gy/fr vs 2.3 Gy/fr, respectively. Finally, Area of pts with and without urinary dysfunctions are well-differentiated only at 2-year, while it is the opposite with hormone-therapy treatment. Conclusion Results from the EORTC QLQ-C30 highlighted a large variability in the deterioration of functional and symptom scales with time. Moderate hypofractionation impacts the QoL acute perception of prostate cancer patients, while diabetes strongly affects the late phase after a better acute condition than the other analyzed characteristics.