High-dose-rate brachytherapy for prostate cancer: Rationale, current applications, and clinical outcome

Development and implementation of a 3d-HDR brachytherapy program for cervical cancer in a sub-Saharan African centre

BACKGROUND

Cervical cancer is the second most common cancer among women in Nigeria where, the gap between need for, and access to, radiation therapy including brachytherapy is significant. This report documents the implementation of the first three-dimensional high-dose-rate (3D-HDR) brachytherapy service for cervical cancer in Nigeria.

PURPOSE

This report details the steps taken to implement the 3D-HDR brachytherapy program, the challenges faced, and the adaptive strategies employed to overcome them. Our objective is to provide a guide for teams and centers in similar resource-restricted settings to implement 3D-HDR brachytherapy services, by leveraging our shared experience and lessons learned.

METHOD AND METERIALS

The implementation process required investment in infrastructure: creating a dedicated brachytherapy suite equipped with modern technology; and human capital: conducting both virtual and hands-on training for staff; and involving international experts during the initial treatment phases. Quality assurance protocols were established to ensure the accuracy and safety of treatments. Key adaptations included extensive remote training, international experts flying in for the initiation phase, and preemptively re-ordering the radioisotope to prevent delays.

RESULTS

The 3D-HDR brachytherapy program was successfully implemented, with five cases treated in the first 2 months despite challenges such as high equipment costs, expertise and proficiency needs, and source replacement delays. Continuous training and quality assurance measures ensured the program's sustainability and effectiveness.

CONCLUSIONS

Implementing a 3D-HDR brachytherapy program in a system with restricted resources is possible with thorough planning, flexible strategies, and adaptive measures. We document our experience to provide insights for other institutions aiming to establish similar programs. Collaboration and innovative financial strategies are essential for ensuring sustainable access to cancer treatment in the region. Strategies such as remote training and proactive resource management, are critical for overcoming implementation barriers.

Evolution and Recent Radiation Therapy Advancement in Uganda: A Precedent on How to Increase Access to Quality Radiotherapy Services in Low- and Middle-Income Countries

The evolution of radiation therapy in Uganda has been a journey marked by significant milestones and persistent challenges. Since the inception of radiotherapy services in 1988-1989, there has been a concerted effort to enhance cancer treatment services. The early years were characterized by foundational developments, such as the installation of the first teletherapy units, low-dose-rate brachytherapy units, and conventional simulators, and the recognition of radiation oncologists and medical physicist professionals laid the groundwork for radiotherapy treatment modalities. With more support from the International Atomic Energy Agency, the acquisition of dosimetry equipment, treatment planning systems, and additional professional training signaled a new era in the fight against cancer. As we entered the second decade of the millennium, the Uganda Cancer Institute (UCI) witnessed a progression in sophisticated radiotherapy services, including high-dose-rate brachytherapy, initiation of intensity modulated radiation therapy (IMRT)/volumetric modulated arc therapy (VMAT), and use of artificial intelligence. These advancements improved the efficiency/precision of treatments and the time patients spent undergoing therapy. Around the second decade of radiotherapy services, about 600 new patients with cancer were annually treated compared with about 2,600 in 2023. Currently, an average of 1,440 brachytherapy insertions are done annually compared with 300 insertions for the first 20 years. Despite the technological strides, the UCI faced numerous obstacles, including limited equipment, knowledge gaps in appropriate tumor/organs at risk segmentations, treatment planning, and protocols. However, international support and collaboration efforts have led to significant improvement in the precision and effectiveness of treatments. Currently, about 51% of all patients are treated with image-guided techniques-IMRT/VMAT (42%) and three-dimensional conformal radiation treatment (10%). The Government has commenced the decentralization of radiotherapy services to other regions. This review can be a learning lesson for the more than 25 countries in Africa and other low-middle-income countries globally that do not have access to radiotherapy and/or are in the process of starting such facilities.

Long-term disease-free survival and health-related quality of life results of high-dose-rate brachytherapy as monotherapy for low and intermediate-risk prostate cancer treated in a community cancer center

PURPOSE

To determine the long-term disease-free survival, long-term toxicity, and effect on health-related quality of life of a two-fraction regimen of high-dose-rate (HDR) prostate brachytherapy.

METHODS AND MATERIALS

Patients with low- or intermediate-risk prostate cancer were treated with CT-planned HDR brachytherapy as monotherapy in two implants of 13.5 Gy in one community cancer center. Prostate-specific antigen (PSA), International Prostate Symptom Score (IPSS) and Expanded Prostate Index Composite (EPIC) questionnaires were evaluated at each follow-up visit. Biochemical recurrence (Phoenix definition) was evaluated to determine disease-free survival at 5 and 7 years. Proportion of patients in each IPSS category (mild = 0-7, moderate = 8-18, severe = 19+) was evaluated at each follow-up interval.

RESULTS

Thirty patients were accrued to the study between 2014 and 2016. Median prostate-specific antigen was 8,7 (range 4.1-17.5). T stages were T1c = 65%, T2a = 21%, and T2b = 14%. Twenty-seven percent of patients had a Gleason score of 6 and 73% had a Gleason score of 7. 13% were in low risk category and 87% in intermediate risk category. Median follow-up was 84 months. There were no deaths at 84 months after brachytherapy. Disease-free survival was 90% at 5 years and 86% at 7 years. Two patients experienced late Grade 3 GU toxicity (6.6%).

CONCLUSIONS

This study serves as proof of concept that HDR monotherapy can be performed successfully with excellent long-term outcomes in a community cancer center with adequate training and experience. The long-term disease-free survival rate and the health-related quality of life seem acceptable as compared to other treatment modalities. Further study is ongoing with regard to the optimal dosing regimen for HDR monotherapy.

Personalised in silico biomechanical modelling towards the optimisation of high dose-rate brachytherapy planning and treatment against prostate cancer

High dose-rate brachytherapy presents a promising therapeutic avenue for prostate cancer management, involving the temporary implantation of catheters which deliver radioactive sources to the cancerous site. However, as catheters puncture and penetrate the prostate, tissue deformation is evident which may affect the accuracy and efficiency of the treatment. In this work, a data-driven in silico modelling procedure is proposed to simulate brachytherapy while accounting for prostate biomechanics. Comprehensive magnetic resonance and transrectal ultrasound images acquired prior, during and post brachytherapy are employed for model personalisation, while the therapeutic procedure is simulated via sequential insertion of multiple catheters in the prostate gland. The medical imaging data are also employed for model evaluation, thus, demonstrating the potential of the proposed in silico procedure to be utilised pre- and intra-operatively in the clinical setting.

Health Professionals' Perceptions about Prostate Cancer-A Focus Group Study

Prostate cancer (PCa) accounts for 20% of new cancer cases and 10.5% of cancer-associated mortality in Portugal. Associated risk factors include advanced age, family history, genetic alterations, and race/ethnicity. However, the role of lifestyle factors is often underestimated. To explore health professionals' perceptions of PCa risk factors, a qualitative study with three focus groups (FG), with a total of twenty-one general practitioners and urologists, was conducted via videoconference between February and April 2023. Seven themes emerged, including general perceptions of PCa; PCa risk factors; nutritional impact; the role of physical activity; alcohol consumption and smoking; sexual activity and sexually transmitted diseases roles in PCa; and screening, diagnosis, and treatment methods. Despite agreeing that healthy lifestyles could promote better PCa outcomes and quality of life, participants did not specify any lifestyle factors that could promote or prevent this disease, posing challenges to lifestyle changes, particularly among older adults. Non-invasive screening methods, such as biomarkers and alternative treatments, are crucial for future research. This study underscores the need for further investigation into the correlation of lifestyle factors with PCa and highlights the necessity of health professionals in encouraging their patients to adopt healthier lifestyles, while offering important insights into awareness, prevention, and alternative screening, diagnosis, and treatment methods, which could help reduce false positives and treatment side effects.

Influence of demographic change on the demand for radiotherapy using forecasted predictions for prostate cancer in Germany

PURPOSE

Demographic change will lead to an increase in age-associated cancers. The demand for primary treatment, especially oncologic therapies, is difficult to predict. This work is an attempt to project the demand for radiation therapy (RT) in 2030, taking into account demographic changes using prostate cancer (PC) as an example.

MATERIALS AND METHODS

Using the GENESIS database of the Federal Statistical Office, we retrieved demographic population projections for 2030 and retrospective demographic surveys from 1999 to 2019. Additionally, we queried incidence rates for PC in the respective age groups of 50-54, 55-59, 60-64, 65-69, 70-74, 75-79, 80-84, and +85 years from 1999-2019 via the Federal Cancer Registry of the Robert Koch Institute. We used a regression method to determine the age-dependent correlation between the incidence of PC and the population size of the respective age group by combining the data from 1999 to 2019. This information was used to calculate the incidence rates in the age groups of the expected population for 2030 and the expected new cases of PC in 2030. Finally, we extrapolated the indications for the demand for RT based on data from the Report on Cancer Incidence in Germany from 2016.

RESULTS

Considering a population-dependent incidence rate, an increase in new cases of PC is expected. This increase is particularly evident in the age groups of 70-74 and 80-84 years. With regards to RT, the estimate indicates an overall increase of 27.4% in demand. There is also a shift in RT demands towards older patients, especially in the 80- to 84-year-old age group.

CONCLUSION

We observe an age-associated increase in primary cases of PC. This is likely to result in an increased demand for RT. The exact demand cannot be predicted. However, trends can be estimated to plan for the demand. This, though, requires a good database from cancer registries.

Epigenetics as a Key Factor in Prostate Cancer

Nowadays, prostate cancer is one of the most common forms of malignant neoplasms in men all over the world. Against the background of increasing incidence, there is a high mortality rate from prostate cancer, which is associated with an inadequate treatment strategy. Such a high prevalence of prostate cancer requires the development of methods that can ensure early detection of the disease, improve the effectiveness of treatment, and predict the therapeutic effect. Under these circumstances, it becomes crucial to focus on the development of effective diagnostic and therapeutic approaches. Due to the development of molecular genetic methods, a large number of studies have been accumulated on the role of epigenetic regulation of gene activity in cancer development, since it is epigenetic changes that can be detected at the earliest stages of cancer development. The presence of epigenetic aberrations in tumor tissue and correlations with drug resistance suggest new therapeutic approaches. Detection of epigenetic alterations such as CpG island methylation, histone modification, and microRNAs as biomarkers will improve the diagnosis of the disease, and the use of these strategies as targets for therapy will allow for greater personalization of prostate cancer treatment.

Preliminary Characterization of an Active CMOS Pad Detector for Tracking and Dosimetry in HDR Brachytherapy

We assessed the accuracy of a prototype radiation detector with a built in CMOS amplifier for use in dosimetry for high dose rate brachytherapy. The detectors were fabricated on two substrates of epitaxial high resistivity silicon. The radiation detection performance of prototypes has been tested by ion beam induced charge (IBIC) microscopy using a 5.5 MeV alpha particle microbeam. We also carried out the HDR Ir-192 radiation source tracking at different depths and angular dose dependence in a water equivalent phantom. The detectors show sensitivities spanning from (5.8 ± 0.021) × 10-8 to (3.6 ± 0.14) × 10-8 nC Gy-1 mCi-1 mm-2. The depth variation of the dose is within 5% with that calculated by TG-43. Higher discrepancies are recorded for 2 mm and 7 mm depths due to the scattering of secondary particles and the perturbation of the radiation field induced in the ceramic/golden package. Dwell positions and dwell time are reconstructed within ±1 mm and 20 ms, respectively. The prototype detectors provide an unprecedented sensitivity thanks to its monolithic amplification stage. Future investigation of this technology will include the optimisation of the packaging technique.

Comparison of chronic gastrointestinal and genitourinary toxicities between brachytherapy and external beam radiotherapy for patients with prostate cancer: A systematic review and meta-analysis

BACKGROUND

125I BT is an effective radiotherapy for prostate cancer. However, comparison data of GI and GU toxicities between BT, BT + EBRT, and EBRT-alone patient groups is limited.

OBJECTIVE

To define the GI and GU toxicities in prostate cancer to prevent adverse events after treatment.

METHODS

We searched published studies in PubMed, Cochrane, and Embase databases up to December 31, 2022. The endpoints were the RRs of GI and GU toxicities. Pooled data were assessed using a random-effects model.

RESULTS

Fifteen eligible studies were included into this analysis. LDR-BT had significantly lower RRs than LDR-BT + EBRT for acute GI (2.13; 95% CI, 1.22-3.69; P= 0.007) and late GI toxicities (3.96; 95% CI, 1.23-12.70; P= 0.02). Moreover, EBRT had significantly higher RRs than LDR-BT for acute GU (2.32; 95% CI, 1.29-4.15; P= 0.005) and late GU toxicities (2.38; 95% CI, 1.27-4.44; P= 0.007). HDR-BT had significantly higher RRs for acute GU toxicities than LDR-BT alone (0.30; 95% CI, 0.23-0.40; P< 0.00001).

CONCLUSION

The results implied that BT with and without EBRT can result in both GI and GU toxicities in patients with prostate cancer, with LDR-BT leading to a poorer urinary function than EBRT.

Stereotactic Radiation Therapy versus Brachytherapy: Relative Strengths of Two Highly Efficient Options for the Treatment of Localized Prostate Cancer

Stereotactic body radiation therapy (SBRT) has become a valid option for the treatment of low- and intermediate-risk prostate cancer. In randomized trials, it was found not inferior to conventionally fractionated external beam radiation therapy (EBRT). It also compares favorably to brachytherapy (BT) even if level 1 evidence is lacking. However, BT remains a strong competitor, especially for young patients, as series with 10-15 years of median follow-up have proven its efficacy over time. SBRT will thus have to confirm its effectiveness over the long-term as well. SBRT has the advantage over BT of less acute urinary toxicity and, more hypothetically, less sexual impairment. Data are limited regarding SBRT for high-risk disease while BT, as a boost after EBRT, has demonstrated superiority against EBRT alone in randomized trials. However, patients should be informed of significant urinary toxicity. SBRT is under investigation in strategies of treatment intensification such as combination of EBRT plus SBRT boost or focal dose escalation to the tumor site within the prostate. Our goal was to examine respective levels of evidence of SBRT and BT for the treatment of localized prostate cancer in terms of oncologic outcomes, toxicity and quality of life, and to discuss strategies of treatment intensification.