Prostate cancer is the second most commonly diagnosed cancer in men and radical prostatectomy is one of the main treatments for the localized stage of this cancer. After radical prostatectomy, more than 30% of patients will experience an increase in the serum level of their prostate specific antigen (PSA) with no metastases or local recurrence being detectable by 99mTc-bone scintigraphy and computed tomography of the thorax and abdomen. This situation is often coined as biochemical recurrence. Depending on several factor, a biochemical recurrence may be associated with a higher overall risk of metastases and death from prostate cancer.
Prostate bed radiotherapy is the recommended local salvage treatment for patients with low-PSA values at recurrence following radical prostatectomy and a negative standard imaging. However, in the past decade, development of molecular imaging with Choline and now PSMA PET has made it possible to detect the site of relapse early in the course of the disease recurrence, leading to a change in the intended treatment, whether it is the radiation field and dose, or the choice to add a systemic treatment. These changes are not standardized among physicians and the clinical benefit that patients derive from this treatment’s changes is for the moment unknown.
Professor Martin Buxton is a hypertension expert, known for his work in economic evaluation of health technologies. He made this famous statement now known as Buxton’s law of technology assessment, which is: “it is always too early for rigorous evaluation of a new technique until, unfortunately, it is suddenly too late”. This statement was made to illustrate what is frequently observed when new health technologies or procedures are introduced, and some may say it might be the case with the introduction of new molecular imaging in the biochemical recurrence setting.
The work presented in this manuscript aims to prove this statement wrong by questioning the utility of these new imaging techniques and trying to provide high level evidence of the best treatment option depending on the imaging’s findings, whether it is a local, a nodal or a metastatic recurrence. The first article presented in this manuscript compared the diagnostic performance of a whole-body 18F-choline hybrid PET/MRI to pelvic multiparametric MRI for prostate cancer patients at biochemical relapse after RP. The second and third articles focus on the randomized phase 2 PEACE V-STORM trial aiming to determine the best treatment option for PET detected nodal recurrence. The fourth article reports the results of SPIDER, an international multicentric retrospective study evaluating the efficacy and safety of functional image-guided salvage RT in patients with a macroscopic relapse in the prostate bed. Finally, the last article is an expert’s consensus for the use of radiation therapy in the oligometastatic setting, in an attempt to standardize the RT treatment of oligometastatic prostate cancer until mature results of randomized trials are available.
