Ultra-Hypofractionated Stereotactic Body Radiotherapy for Localized Prostate Cancer: Clinical Outcomes, Patterns of Recurrence, Feasibility of Definitive Salvage Treatment, and Competing Oncological Risk

Incidence and Outcomes of Secondary Bladder Cancer Following Radiation Therapy for Prostate Cancer: A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVE

There is an established association between secondary bladder cancers (SBCs) and radiotherapy (RT) for prostate cancer (PC), which remains a significant concern. Our aim was to update the evidence on SBC incidence across different RT modalities and to compare oncological outcomes for patients diagnosed with SBC to those diagnosed with primary bladder cancer (PBC).

METHODS

We searched MEDLINE, Scopus, and Web of Science for studies on SBC following PC. Pairwise meta-analyses were conducted to compare SBC incidence in terms of odds ratios (ORs) between RT modalities (external beam radiation therapy [EBRT], brachytherapy [BT], and BT + EBRT) and PBC incidence after radical prostatectomy (RP). SBC incidence data are presented as proportions, and pairwise meta-analyses were used to compare overall survival (OS) between SBC and PBC using hazard ratios (HRs).

KEY FINDINGS AND LIMITATIONS

Thirty-one studies (n = 576 341) were included. All RT modalities significantly increased the risk of SBC in comparison to RP at all time points investigated. BT alone had similar long-term SBC risk in comparison to EBRT (OR 0.56, 95% confidence interval [CI] 0.25-1.23 at 10 yr; OR 0.51, 95% CI 0.24-1.06 at 15 yr). There was no significant difference in OS between SBC and PBC in the overall cohort. However, among patients requiring radical cystectomy (RC), SBC resulted in a significant decrease in OS in comparison to PBC (HR 1.55, 95% CI 1.06-2.26; p = 0.02).

CONCLUSIONS AND CLINICAL IMPLICATIONS

All RT modalities increased the risk of SBC at each post-RT time point investigated. SBC patients requiring RC have worse survival than those with PBC. Our results highlight the need for ongoing surveillance and early detection. Despite the rarity of SBC, clinicians should monitor bladder symptoms in PC patients after RT. These data need to be included in the shared decision-making process with patients regarding therapeutic decisions to raise awareness of SBC in this setting.

Incidence and associated factors of developing second pelvic malignant neoplasms among prostate cancer patients treated with radiotherapy

Objective

To identify risk factors of secondary pelvic malignant neoplasms (SPMNs) among prostate cancer (PCa) patients treated with radiotherapy. Simultaneously, population-based data were used to validate the high risk of SPMNs in PCa patients with radiotherapy.

Materials and methods

We identified male patients diagnosed with PCa (localized and regional) as the first primary cancer and pelvic malignant neoplasm (including bladder and rectal cancer) as secondary cancer from Surveillance, Epidemiology, and End Results database (1975-2020). An external validation cohort was obtained from the First Affiliated Hospital of Nanchang University. The Fine-Gray competing risk regression and Poisson regression were utilized to evaluate the risk of SPMNs development. Poisson regression was also performed to calculate the standardized incidence ratio (SIR). The Kaplan-Meier method was used to assess the overall survival (OS) of patients with SPMNs.

Results

89397 PCa patients treated with radiotherapy were enrolled. We identified associated factors of SPMNs, including age at diagnosis, race, year of diagnosis, marital status, radiation strategy and latency. In the multivariable competing risk regression model and Poisson regression model, a significantly higher risk of SPMNs development was observed in patients over 50 years(P<0.05), white patients(P<0.001), unmarried patients and treated with brachytherapy combined with external beam radiotherapy or brachytherapy(P<0.05). Patients treated with radiotherapy had a higher bladder and rectal cancer incidence than the general population. Patients who developed SPMNs showed poorer OS.

Conclusion

We identified several risk factors associated with SPMNs and confirmed a relatively higher incidence of bladder and rectal cancer among PCa patients with radiotherapy. These results help tailor treatment and surveillance strategies.

5-Years Analysis of Effectivity and Toxicity of Ultra-Hypofractionated Proton Radiotherapy in the Treatment of Low- and Intermediate-Risk Prostate Cancer-A Retrospective Analysis

BACKGROUND

We retrospectively analyzed the 5-year biochemical disease-free survival (bDFS) and occurrence of late toxicity in prostate cancer patients treated with pencil beam scanning (PBS) proton radiotherapy.

METHODOLOGY

In the period from January 2013 to June 2018, 853 patients with prostate cancer were treated with an ultra-hypofractionated schedule (36.25 GyE/five fractions). The mean PSA value was 6.7 (0.7-19.7) µg/L. There were 318 (37.3%), 314 (36.8%), and 221 (25.9%) patients at low (LR), favorable intermediate (F-IR), and unfavorable intermediate risk (U-IR), respectively. Neoadjuvant hormonal therapy was administered to 197 (23.1%) patients, and 7 (0.8%) patients had adjuvant hormonal therapy. The whole group of patients reached median follow-up time at 62.7 months, and their mean age was 64.8 (40.0-85.7) years. The bDFS rates and late toxicity profile were evaluated.

RESULTS

Median treatment time was 10 (7-38) days. Estimated 5-year bDFS rates were 96.5%, 93.7%, and 91.2% for low-, favorable intermediate-, and unfavorable intermediate-risk groups, respectively. Cumulative late toxicity (CTCAE v4.0) of G2+ was as follows: gastrointestinal (GI)-G2: 9.1%; G3: 0.5%; genitourinary (GU)-G2: 4.3%, and no G3 toxicity was observed. PSA relapse was observed in 58 (6.8%) patients: 16 local, 22 lymph node, 4 bone recurrences, and 10 combined sites of relapse were detected. Throughout the follow-up period, 40 patients (4.7%) died, though none due to prostate cancer.

CONCLUSION

Ultra-hypofractionated proton beam radiotherapy is an effective treatment for low- and favorable intermediate-risk prostate cancer, with long-term bDFS rates comparable to other techniques. It is promising for unfavorable intermediate-risk prostate cancer and has acceptable long-term GI and favorable GU toxicity.

Hypofractionated Radiotherapy in Localized, Low-Intermediate-Risk Prostate Cancer: Current and Future Prospectives

At the time of diagnosis, the vast majority of prostate carcinoma patients have a clinically localized form of the disease, with most of them presenting with low- or intermediate-risk prostate cancer. In this setting, various curative-intent alternatives are available, including surgery, external beam radiotherapy and brachytherapy. Randomized clinical trials have demonstrated that moderate hypofractionated radiotherapy can be considered as a valid alternative strategy for localized prostate cancer. High-dose-rate brachytherapy can be administered according to different schedules. Proton beam radiotherapy represents a promising strategy, but further studies are needed to make it more affordable and accessible. At the moment, new technologies such as MRI-guided radiotherapy remain in early stages, but their potential abilities are very promising.