Risk of severe late toxicity after radiotherapy following radical prostatectomy - a nationwide study.

OBJECTIVE: To estimate the long-term risks of severe late toxicities for radiation therapy (RT) following radical prostatectomy (RP) in an unselected nationwide cohort, as severe side-effects are rare but may occur years later. PATIENTS AND METHODS: The study population comprised all men undergoing RP between 1997 and 2016 in the Prostate Cancer database Sweden (PCBaSe) (n = 40 962). By (1:2) matching, two cohorts were created: 2789 men exposed to postoperative RT and 5578 unexposed men with comparable age, comorbidities, and year of surgery. Cumulative incidences and rate ratios were calculated for the following outcomes: symptoms and interventions of the urinary or intestinal tract demanding inpatient care, secondary malignancies, and non-prostate cancer mortality. RESULTS: The largest differences were seen for late toxicities affecting the urinary tract. The 10-year cumulative incidences among those exposed to postoperative RT vs the RP-only group were: 17.8% vs 10.5% for procedures of the urinary tract (difference 7.3%, 95% confidence interval [CI] 4.4 to 10.3; relative risk [RR] 1.74, 95% CI 1.47 to 2.05); 6.0% vs 1.2% for haematuria (difference 4.8%, 95% CI 3.1 to 6.5; RR 6.50, 95% CI 4.31 to 10.10); and 2.4% vs 1.1% for bladder cancer (difference 1.4%, 95% CI 0.4 to 2.3; RR 2.71, 95% CI 1.72 to 4.33). The groups were similar regarding intestinal toxicity, other secondary malignancies, and non-prostate cancer mortality. Adjustments for preoperative tumour risk factors did not importantly affect the rate ratios. CONCLUSION: Severe late toxicity after postoperative RT following RP predominately affects the bladder and can appear many years after RT.

A comparison of side-effects and quality-of-life in patients operated on for prostate cancer with and without salvage radiation therapy.

PURPOSE: The extent of late side-effects in prostate cancer patients, after radical prostatectomy (RP = reference group) and salvage radiation therapy (SRT) in a self-reporting perspective (PROM) is still under-reported. We aimed to investigate the rate and severity of side-effects and quality-of-life (QoL) according to PROM. METHODS AND MATERIALS: A PROM survey was administered to a cohort of SRT patients matched to a reference group with median follow-up 10 years after surgery. In total, 740 patients were analyzed. To investigate the association between SRT versus reference group regarding side-effects and QoL, a Poisson regression analysis was conducted and presented as relative risk estimates (RR) together with 95% confidence intervals regarding questions related to urinary, rectal, sexual symptoms and QoL. RESULTS: RRs ranged from of 1.7-6.5 on rectal symptoms and 1.2-1.4 for urinary symptoms. In general health, QoL and sexual function all RRs were below 1.1. With increasing age, higher RRs were seen for urinary leakage and lowered sexual function whereas longer time following irradiation showed higher RRs for rectal symptoms and rectal leakage. Limitations of this study include the cross-sectional design and lack of baseline assessment. CONCLUSIONS: Adding SRT to RP does not seem to result in other than acceptable side-effects in the majority of men receiving SRT when taking a long follow-up time (median 10 years after surgery) into account. However, a subset of men develop severe side-effects where rectal bleeding dominates.

The value of a bladder-filling protocol for patients with prostate cancer who receive post-operative radiation: results from a prospective clinical trial.

BACKGROUND AND PURPOSE: This study compares two different strategies for maintaining a constant bladder volume during a course of postoperative radiotherapy in prostate cancer. In addition, we studied how changes in bladder filling affect the clinical target volume (CTV) and the coverage hereof. MATERIAL AND METHODS: Twenty-nine patients with PSA-relapse after radical prostatectomy were divided into two groups: voiding and drinking 300 ml 1 hour before treatment (Group 1); and maintained a comfortably filled bladder (Group 2). The bladder volumes were calculated based on the planning CT (pCT) and a weekly Cone Beam CT (CBCT) during the treatment period. Furthermore, the variability of bladder extension was analyzed and correlated to the volume of the bladder covered with the 95% of the dose (V95%,bladder). RESULTS: The estimated median bladder volumes were 120 ml (95% CI: (93, 154)) and 123 ml (95% CI: (98, 155)) in groups 1 and 2, respectively. The intra-individual variation in bladder volume, assessed as the standard deviation, was 64 ml (95% CI: (46, 105)) in Group 1 and 61 (95% CI: (45, 94)) ml in Group 2. Increasing the bladder volume extended the bladder cranially while the caudal extension was almost constant. The correlation between bladder volume and V95%,bladder was 3.5 ml per 100 ml in group 1 and 1.2 ml per 100 ml in group 2 with no significant difference. CONCLUSIONS: The intention to maintain a constant volume for the bladder is not fulfilled with either of the protocols in this study, and changes in bladder volumes does not seem to affect the position, or the coverage of the CTV.

Clinical feasibility and positional stability of an implanted wired transmitter in a novel electromagnetic positioning system for prostate cancer radiotherapy.

PURPOSE: Three aspects of the RayPilot real-time tracking system were investigated: (1) feasibility of the transmitter with respect to implantation and explantation procedures, (2) user and patients' experiences and (3) quantification of the transmitter positional stability in relation to fiducial markers. METHODS AND MATERIALS: Ten prostate cancer patients scheduled for radiotherapy received transmitter implantation in the prostate, concomitantly with fiducial markers. Transmitter and marker positions were assessed in 3D by orthogonal kV-imaging at daily treatment setup in eight patients. RESULTS: The transmitter was successfully implanted in all patients. Patients reported mild to moderate discomfort and impact on daily activities due to the implant but overall subjective tolerability was good. One patient had spontaneous explantation of the transmitter after four fractions. One patient had transmitter 3D shifts >9 mm, but also inter-marker shifts >6 mm. The mean inter-marker shift in the remaining patients was <1 mm. In four patients, maximum transmitter 3D shifts were 5-7 mm (mean >2 mm). In three patients, mean transmitter 3D shifts were <2 mm. CONCLUSIONS: Implantation and explantation of the transmitter is generally feasible and safe. Patient tolerability is good overall. However, due to interfractional transmitter positional instability in this cohort, use of the system for real-time tracking should be combined with other daily setup techniques.

Effective oral combination metronomic chemotherapy with low toxicity for the management of castration-resistant prostate cancer.

Prostate cancer (PC) was previously believed to be a chemoresistant disease. In recent years taxane-based chemotherapy has been shown to prolong survival in patients with castration-resistant prostate cancer (CRPC). It remains to be shown, however, which type of chemotherapy provides the most beneficial effect with the least amount of side effects. Seventeen patients with chemonaive CRPC were enrolled in a pilot study evaluating an orally administered chemo-hormonal treatment regimen using a weekly sequential combination called KEES; consisting of ketoconazole in combination with cyclophosphamide or etoposide in combination with estramustine administered on alternate weeks. Prednisone was administered throughout the treatment period. Prostate-specific antigen (PSA) response and acute and chronic toxicities were evaluated. Seventeen patients with CRPC were treated; eleven patients demonstrated a median reduction in PSA of 87% (range 26-99%). Ten (59%) patients responded with a decrease in PSA >50%. Thrombocytopenia and anaemia were the most common side effects. One study fatality was reported, however, it was unclear whether this was treatment related. In conclusion, KEES may be a promising option for patients with CRPC, resulting in a clear reduction in PSA with limited toxicity. Further clinical evaluation of this metronomic chemohormonal combination is underway.

High precision transponder localization using a novel electromagnetic positioning system in patients with localized prostate cancer.

BACKGROUND AND PURPOSE: The Micropos 4DRT system is being developed to provide accurate, precise, objective, and continuous target localization during radiotherapy. This study involves the first in vivo use of the system, aiming to evaluate the localization accuracy of this electromagnetic positioning technique compared with radiographic localization and to assess its real-time tracking ability. MATERIAL AND METHODS: An active positioning marker was inserted in the prostatic urethra of 10 patients scheduled to receive radiotherapy for localized prostate cancer. A receiving sensor plate (antennae system) was placed at a known position in the treatment tabletop. Initial in vivo system calibrations were performed in three subjects. Ten additional patients were then enrolled in a study arm that compared radiographic transponder location to radiotransponder location simultaneously acquired by the Micropos 4DRT system. Frontal and side radiographs were taken with the radiopaque transponder located at three different positions within the prostatic urethra. RESULTS: The transponder insertions were all successful and without complications. Comparison of the transponder location as per the Micropos 4DRT system with the radiographic transponder localization showed an average (+/-SD) absolute and relative 3D difference of 2.7+/-1.2 and 1.7+/-1.0mm, respectively. Continuous transponder tracking capability was also demonstrated. CONCLUSIONS: Electromagnetic positioning using the Micropos transponder system is feasible in vivo. Evaluation of this novel non-ionizing localization system, in this study using a transponder positioned in the prostatic urethra, indicates transponder localization accuracy to isocenter comparable with X-ray localization of a radiopaque marker.