Session Item

The prostate adenocarcinoma is the most frequent cancer in men with an annual incidence of 50 400 new cases in France. One of the greatest therapeutic options for the early staged cancers is external radiotherapy. Although hypofractionated radiotherapy has proven a similar efficacity to external radiotherapy, it still isn’t a standard in France. The main purpose of this study is to evaluate the tolerance during and after treatment (4-6 months and 5 years post exposition) among patients that were treated with mild hypofractionated radiotherapy with dose escalation for a prostatic adenocarcinoma. We will also report the data on progression-free survival, specific survival and global survival.

212 patients were treated consecutively between February 2016 and March 2018.  The dose of 75 Gy was delivered in 30 fractions to the prostate and the proximal seminal vesicles (eqd2 = 82.5 to 85.7 Gy delivered in fractions of 2 Gy for an α/β of 1.5 à 3). A hundred and ninety-five patients (92 %) also received a pelvic lymphatic irradiation (46 Gy delivered in 23 fractions). The irradiation technique that was used was a rotational RCMI (Rapidarc® ) guided by sight after the implantation of 3 intra-prostatic golden grains. Genito-urinary and gastro-intestinal toxicities were analyzed during treatment, after 4 to 6 months and after 5 years of follow-up according to CTCAEv5. We also looked for predictive factors of toxicity and survival.

A total of 166 patients were included. Their characteristics were : Medium age = 71.4 ans [52.9—85.6] / Medium initial PSA rate = 9 ng/mL [2.6—111] / Stade T1, T2, T3, T4 respectively 34.3 %, 26.5 %, 38.5 % and 0.6 % / Gleason Score 6, 7 (3 + 4), 7 (4 + 3) and ≥ 8 respectively 22.9 %, 43.4 %, 23.5 % and 10.2 %. We excluded patients with lymph node involvement and patients with metastasis. 

Grade ≥ 2 genito-urinary toxicities that occurred during treatment, after 4-6 months and after 5 years of follow-up were respectively of 36.7%, 8.8% and 4.7% and grade ≥ 2 gastro-intestinal toxicities of 15.1%, 1.9% et 9.3%. We reported one grade 3 genito-urinary toxicity, two grade 4 genito-urinary-toxicities, twelve grade 3 gastro-intestinal toxicities and no grade 4 gastro-intestinal toxicity. No link was found between the occurrence of these toxicities and the other parameters that we analyzed.

    Only 15 patients had a progression of their cancer. After 5 years of follow-up, the progression-free survival was of 85.7%, the specific survival was of 93.3% and the global survival was of 82.4%. We only found the PSA rate and the cardiovascular risk factors to be significatively associated to the global survival in the multivariate analysis.

Mild hypofractionated prostatic radiotherapy with dose escalation is well tolerated and adds no toxicity compared to a normo-fractionated plan. Moreover, it considerably helps reducing the total duration of the treatment. These encouraging results must be confirmed with a phase III randomized trial.