ESTRO 2024 - Abstract Book

S2484

Clinical - Urology

ESTRO 2024

Longer life expectancy has led to a significant increase in the number of elderly patients (pts) with localized prostate cancer (PCa) who are potential candidates for curative radiotherapy (RT). Pts aged ≥ 80 years often present a high prevalence of comorbidities with a potential impact on treatment tolerance. The aim of the present study (Ethical Committee approval UID 2684) is to evaluate the efficacy and safety of ultra-hypofractionated RT (UHRT) +/- androgen deprivation therapy (ADT) in this setting of pts.

Material/Methods:

Elderly men aged ≥80 years with localized PCa who underwent curative UHRT between 2012 and 2022 were retrospectively included. Risk groups were determined based on NCCN definitions. Biochemical progression (BP) was assessed according to Phoenix definition while clinical progression (CP) was defined as the presence of local, regional or distant metastatic sites at radiological imaging. Gastrointestinal (GI) and genitourinary (GU) toxicities were collected according to RTOG scale. Continuous variables were summarized as mean/median and interquartile range/range, while categorical variables were presented with absolute and relative frequencies. All pts provided written informed consent for treatment and consent for the use of the anonymized data for research purposes.

Results:

A total of 181 pts fulfilled inclusion criteria (Table 1). Median age at diagnosis was 82 years (range 80 - 95) and median iPSA was 7.625 ng/ml (range 0.72-220.4). The majority of pts (n = 116, 64 %) had a Charlson Comorbidity Index (CCI) of six and the most frequent comorbidities were diabetes mellitus (n = 120, 66.3%) and heart failure/myocardial infarction (n = 60, 33.2%), followed by localized second malignancy (27, 14.9%) and cerebrovascular disease (n = 16, 8.8%). A total of 63 (34.8%) and 33 (18.2%) pts were on regular anticoagulant and antiaggregant therapy, respectively. Stratifying pts according to risk classes, the majority (62, 34.3 %) was classified in the high risk group, 60 (33.1%) in the favourable intermediate group, 40 (22.1%) in the unfavourable intermediate and 18 (9.9%) in the low risk group. All pts underwent UHRT on prostate in 5 fx every other day with a dose/fx between 6.25 and 7.25 Gy with a median CTV prostate volume of 56.6 cc (IQR 42.2 – 73.1, data available for 154 patients). Multiparametric MRI was available for 86 pts. Simultaneous integrated boost (SIB) on dominant intraprostatic lesions of 7.5/8 Gy fx was administered to 69 pts. According to risk class, the majority of pts (n = 100, 55.3%) underwent concomitant ADT with a median duration time of 12.0 months (IQR 6.1 – 12.7, data available for 75 pts). The median follow-up (FU) was 24 months (IQR 13.1 – 34.8, FU available for 156 pts) and median PSA at last FU (available for 141 pts) was 0.5 ng/ml. A total of 17 pts (10.9%) experienced a BP, with a median time from the end of RT of 24.6 months (IQR 15.7 – 29.9). Nine developed a CP (one intraprostatic relapse, two pelvic lymphnodal progression, and six distant progression) of disease (respectively six, two, and one, in high, unfavorable intermediate and favourable intermediate risk classes). GU and GI ≥ G2 acute maximum toxicity was observed for 7 (3.9%) and 3 (1.7%) pts respectively. Considering pts with availability of maximum late toxicities data (n = 126, 70%), 31 and 8 pts experienced G1 and G≥2 late GU toxicities, respectively, while 3 and 5 pts experienced G1 and G≥2 late GI toxicities (Table 2).