Radiotherapy Outperforms Chemoradiation With or Without Short-Term ADT in Prostate Cancer

There was no difference in the occurrence of late toxicities, which was low, between 2 arms of patients treated with radiotherapy alone or radiotherapy with short-term androgen deprivation therapy (STADT) with degarelix as treatment of patients prostate cancer with detectable prostate-specific antigen (PSA) after a radical prostatectomy, according to the phase 2 GETUG-AFU 22 study.

Results were presented in a poster during the 35th Annual European Association of Urology Virtual Congress by Paul Sargos, MD, of Insitut Bergonié, in Bordeaux, France.

The GETUG-AFU 22 study is a multicenter, randomized study. A total of 125 patients were enrolled between December 2012 and September 2015, which led to 64 patients included in the radiotherapy arm (arm A) and 61 patients in the radiotherapy plus STADT arm (arm B).

The primary end point of the study was event-free survival, and the secondary end points included 5-year EFS and metastases-free survival, 5- and 10-year overall survival, acute and late toxicities related to the study treatment, acute and late toxicities related to the radiotherapy modality, and quality of life (QOL).

After 38.1 months of follow-up, all patients were assessable for late toxicities in arms A and B. In terms of later bladder or urethra toxicities, 42 patients (65.63%) versus 39 (63.93%) experienced grade 0 toxicities, 14 (21.88%) versus, 17 (27.87%) experienced grade 1 toxicities, and 8 (12.5%) versus 20 (32.79%) experienced grade 2 toxicities, while no grade 3 or greater toxicities were experienced among arm A versus arm B, respectively (P =.609).

In terms of rectum, or gastrointestinal, late toxicities, 54 patients (84.38%) versus 51 (83.61%) experienced grade 0 toxicities, 8 (12.5%) versus 10 (16.39%) experienced grade 1 toxicities, and 2 (3.13%) versus 0 (0%) experienced grade 2 toxicities, while no grade 3 or greater were observed in arm A versus arm B, respectively (P =.453).

Overall, no differences were observed for erectile dysfunction between the 2 treatment arms, and no differences were observed for cardiovascular disorders. Grade 3 cardiovascular disorders occurred in 2 patients in each arm, which included tight coronary stenosis and femoral arteritis in arm A and pulmonary embolism and cardiac arrhythmia in arm B.

Patients in arm A had two second cancer versus 4 second cancers in arm B, which was not significantly different.

In arm A versus arm B, QLQ-C30 was observed in 56 (88%) versus 60 (98%) at baseline, 51 (80%) versus 54 (89%) at the end of radiotherapy, 51 (80%) versus 54 (89%) after 12 months of follow-up, and 38 (59%) versus 47 (77%) after 24 months of follow-up, respectively. QLQ-PR25 in arm A versus arm B was 55 (86%) versus 60 (98%) at baseline, 52 (81%) versus 54 (89%) after the end of radiotherapy, 50 (78%) versus 54 (89%) after 12 months of follow-up, 38 (59%) versus 47 (77%) after 24 months of follow-up, respectively.

According to the QOL assessment, the QLQ-PR25 HT-related symptoms were significantly higher in the radiotherapy-HT arm at 12 months (P =.04). At 24 months, there was no significant difference in QLQC-30 or the QLQ-PR25 analysis.

The QOL questionnaires demonstrated no differences as well between the 2 different treatment arms. The final efficacy results are still pending.

The purpose of the study was to compare the use of radiotherapy versus radiotherapy with STADT in the persistent post-operative PSA setting for efficacy, safety, and QOL.

The median age of was 66 years (range, 50-77) among all patients on the study, 66 years (range, 51-77) in arm A, and 68 years (range, 50-76) in arm B. The performance status was 0 in 114 patients overall (91.94%), including 57 patients from arm A (89.6%) and 57 patients from arm B (95.0%). In terms of tumor characteristics, 41 patients (32.80%), including 17 (26.56%) from arm A and 24 (39.34%) in arm B, had R0 tumors; 82 (65.60%), including 46 (71.88%) from arm A and 36 (59.02%) in arm B, had R1 tumors; and 2 (1.60%), 1 (1.56%) from arm A and 1 (1.64%) from arm B, had Rx tumors.

The pT stage was most commonly T3, in 79 patients (63.2%), including 43 (67.19%) from arm A and 36 (59.02%) in arm B. The pN stage was also most commonly N0 in 103 patients overall (82.40%), including 55 (85.94%) in arm A and 48 (78.69%) in arm B. The median total Gleason score was 7 in the overall population (range, 3-9), 7 in arm A (range, 3-9), and 7 in arm B (range, 6-9).

To be included in the study, patients had to have localized prostate adenocarcinoma that has been treated with proctectomy, regardless of the initial prognostic stage. They also had to have either R0 or R1, pN0 or pNx, a PSA post-prostatectomy of ≥2 ng/ml between 1 and 4 months after surgery and increasing on a second dosage between 1 and 8 months post-prostatectomy, a PSA ≤2 ng/ml at the time of randomization, and no clinical signs of progressive disease.

_Reference

_{Sargos P, Guerif S, Fraisse J, et al. According to the QOL assessment, the QLQ-PR25 HT-related symptoms were significantly higher in the radiotherapy-HT arm at 12 months (P =.04). At 24 months, there was no significant difference in QLQC-30 or the QLQ-PR25 analysis. Presented at: 35th Annual European Association of Urology Congress; July 20-26, 2020; Virtual. Poster 925.}