Longitudinal Evaluation of Intestinal, Haematological and Urinary Toxicity From Pelvic Irradiation for Prostate Cancer

Experimental Design:

Hypothesis. Dose-volume histograms (DVHs) of bowel, sigmoid colon and rectum are expected to be predictive of IT prospectively self-assessed by patients by means of IBDQ (Inflammatory Bowel Disease Questionnaire). Similarly, DVHs of pelvic bony subvolumes (lumbar-sacral, iliac and the lower pelvis) should predict HT, while DVHs and dose-surface histograms (DSHs) of the bladder are expected to be predictive of UT self-assessed by patients by means of IPSS (International Prostate Symptoms Score) and ICIQ-SF (International Consultation on Incontinence Questionnaire- short form) questionnaires. Moreover, some specific urinary and intestinal-rectal symptoms are expected to lead to impairment in emotional, social and systemic domains, as assessed by the IBDQ questionnaire, more than others, with several possible "clusters" of symptoms prevailing in different treatment settings. Finally, the intestinal, urinary and hematologic toxicity profile of WPRT IMRT could emerge to be extremely different in patients treated with radical (RAD), adjuvant (ADV) or salvage (SALV) intent.

Task1. The principal aim of the project is to develop sophisticated quantitative predictive models of IT, UT and HT (without the confounding bias of chemotherapy) from WPRT IMRT in both radical and postoperative treatment of localized PCa. The possible correlation between the radiation doses received by different pelvic structures and different toxicities will be analyzed.

Task2. To try to individuate the intestinal/rectal and urinary symptoms most negatively affecting the Emotional, Social and Systemic patient domains, with the ultimate objective of "focusing" the quantitative predictive models including both clinical and physico-dosimetric parameters only upon these main symptoms. This approach could theoretically permit the creation of a "shortened and radiotherapy adapted" version of the IBDQ questionnaire.

Task3. A thorough assessment of the different self-assessed toxicity profiles to be expected in patients treated with RAD, ADV or SALV intent will be carried out, with the ultimate aim of accumulating a set of extremely detailed information to be provided to patients in order to offer them appropriate counselling after the initial diagnosis of PCa with regard to the choice between radiotherapy vs surgery. In those selecting the latter and in the presence of risk factors at prostatectomy suggesting a possible role for postoperative radiotherapy, the ultimate objective would be that of assisting patients in the always extremely problematic choice between immediate adjuvant and timely, postponed, salvage irradiation in the case of biochemical recurrence.