Background and purpose: Biochemical recurrence after prostatectomy is commonly treated with salvage radiotherapy (SRT). In this prospective observational study we investigated the PSA decay rate, determined by predefined serial PSA measurements during SRT, as a predictor for treatment outcome. Materials and methods: Between 2013 and 2016, 214 patients were included in the study. The prescribed dose to the prostate bed was 70 Gy in 35 fractions (7 weeks) without hormonal treatment. PSA was measured weekly during SRT. Assuming first order kinetics, a PSA decay-rate constant (k) was calculated for 196 eligible patients. The ability of k to predict disease progression was compared with known clinical prediction parameters using Cox regression, logistic regression and ROC analyses. Disease progression was defined as continuously rising PSA after SRT, PSA increase by ≥0.2 ng/ml above nadir after SRT, hormonal treatment or clinical progression. Results: After a median follow up of 4.7 years the estimated failure-free survival at 5 years was 56%. The PSA decay-rate constant (k) was found to be the strongest predictor of disease progression in both uni-and multivariable analyses. Conclusion: The addition of k to established clinical variables significantly improves the possibility to predict treatment outcome after SRT and could be used to personalize future therapies.

A successful prostatectomy involves removal of all prostatic tissue leading to unmeasurable PSA blood levels. in case of disease recurrence, the PSA will eventually begin to rise. this can either be due to a local relapse, lymph node involvement or distant metastases. the most widely used definition of biochemical failure is that of the American Urological Association (AUA). this is defined as a serum PSA  0.2 ng/ml confirmed by a second determination. Unfortunately there is no method available to date that is capable of differentiating between patients with a true local recurrence and those where the disease is located outside of the prostate/seminal vesicle bed. the former group is expected to benefit from local radiotherapy and thus it would be ideal to be able to develop methods to identify these patients. Current practice involves the use of several prognostic factors, such as surgical margins, PSA doubling time and seminal vesicle involvement to identify patients with high probability of local recurrence that would benefit from salvage radiotherapy [1–4]. According to a meta-analysis by King, including 41 studies on salvage radiotherapy, around 54% of patients receiving radiotherapy (70 Gy) attain relapse-free survival after 3–5 years [5]. this also means that a large proportion of these patients only experience side effects without any treatment benefit either due to a local treatment failure, or perhaps more commonly, undetectable disease outside of the prostate/seminal vesicle bed at the time of treatment. Development of methods to identify patients who already have disease deposits that are not covered with traditional salvage radiotherapy would allow one to either intensify this treatment (e.g. hormonal therapy or lymph-node irradiation) or to inhibit it altogether in case of distant metastases. it has been shown that circulating tumour cells (CtCs) can be identified in patients with metastatic prostate cancer [6]. Whether it is possible to detect these cells at an earlier disease stage, i.e. before distant metastases can be confirmed by imaging modalities, is not well studied. Lowes et al. reported that patients with PSA recurrence had CtCs in the blood in 73% of the cases at pre-treatment [7]. interestingly patients with CtCs were less likely to respond to treatment. this could indicate that presence of CtCs in blood could be used as a predictive factor during treatment of patients with a recurrent prostate cancer. the aim of this study was to prospectively evaluate the prevalence of CtCs in patients with PSA recurrence and correlate it to treatment outcome.

Background: Low-dose rate brachytherapy (LDR-BT) has been used in Sweden for more than a decade for treatment of low-risk prostate cancer. This study presents the outcome for patients treated with LDR-BT at a single institution with focus on the association between dose and biochemical failure-free survival (BFFS).Methods: In total 195 patients were treated with LDR-BT between 2004 and 2008. The patients were followed systematically for side effects for at least one year. PSA levels were followed regularly from three months and for at least five years. Outcome was analyzed in relation to clinical variables at baseline and to radiotherapy data.Results: Kaplan-Meier estimated BFFS at five years was 95.7%. Dose to the prostate in terms of D-90% was significantly associated with BFFS [HR 0.90 (95%CI 0.83-0.96), p=0.002].Conclusion: Out data confirmed that absorbed dose is a predictive factor for BFFS for low-risk patients without androgen deprivation therapy. With our treatment routines and dosimetry, a D-90% in the range of 170-180Gy gives excellent outcomes with acceptable toxicity for patients with low-risk prostate cancer.

Regarding “Comparative effectiveness of radical prostatectomy and radiotherapy in prostate cancer : observational study of mortality outcomes”, BMJ. 2014 Feb 26;348

The aim of the present study was to evaluate the prevalence and severity of lower limb lymphedema after pelvic lymphadenectomy and radiotherapy to the pelvic lymph nodes in patients with prostate cancer.