The evolution of brachytherapy for prostate cancer

The expanding role of radiation oncology across the prostate cancer continuum

Radiotherapy is used in the treatment of prostate cancer in a variety of disease states with significant reliance on imaging to guide clinical decision-making and radiation delivery. In the definitive setting, the choice of radiotherapy treatment modality, dose, and fractionation for localized prostate cancer is determined by the patient's initial risk stratification and other clinical considerations. Radiation is also an option as salvage therapy in patients with locoregionally recurrent disease after prior definitive radiation or surgery. In recent years, the role of radiation has expanded for patients with metastatic disease, including prostate-directed radiotherapy in de novo low volume metastatic disease, metastasis-directed therapy for oligorecurrent disease, and palliative management of symptomatic metastases in the advanced setting. Here we review the expanding role of radiation in the treatment of prostate cancer in the definitive, locoregionally recurrent, and metastatic settings, as well as highlight the role of imaging in clinical reasoning, radiation planning, and treatment delivery.

Iodine-125 seed inhibits proliferation and promotes apoptosis of cholangiocarcinoma cells by inducing the ROS/p53 axis

With advances in radioactive particle implantation in clinical practice, Iodine-125 (125I) seed brachytherapy has emerged as a promising treatment for cholangiocarcinoma (CCA), showing good prognosis; however, the underlying molecular mechanism of the therapeutic effect of 125I seed is unclear. To study the effects of 125I seed on the proliferation and apoptosis of CCA cells. CCA cell lines, RBE and HCCC-9810, were treated with reactive oxygen species (ROS) scavenger acetylcysteine (NAC) or the p53 functional inhibitor, pifithrin-α hydrobromide (PFTα). Cell counting kit-8 (CCK-8) assay, 5-bromo-2-deoxy-uridine (BrdU) staining, and terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay and flow cytometry assay were performed to test the radiation-sensitivity of 125I seed toward CCA cells at different radiation doses (0.4 mCi and 0.8 mCi). 2,7-dichlorofluorescein diacetate (DCF-DA) assay, real-time quantitative polymerase chain reaction (RT-qPCR), and western blot analysis were performed to assess the effect of 125I seed on the ROS/p53 axis. A dose-dependent inhibitory effect of 125I seeds on the proliferation of CCA cells was observed. The 125I seed promoted apoptosis of CCA cells and induced the activation of the ROS/p53 pathway in a dose-dependent manner. NAC or PFTα treatment effectively reversed the stimulatory effect of 125I seed on the proliferation of CCA cells. NAC or PFTα suppressed apoptosis and p53 protein expression induced by the 125I seed. 125I seed can inhibit cell growth mainly through the apoptotic pathway. The mechanism may involve the activation of p53 and its downstream apoptotic pathway by up-regulating the level of ROS in cells.

Radiation proctitis after iodine-125 low-dose-rate prostate brachytherapy utilizing SpaceOAR hydrogel

OBJECTIVE

We retrospectively evaluated the efficacy of combining the SpaceOAR (SOAR) hydrogel with prostate brachytherapy, using colonoscopy findings to assess for radiation proctitis.

METHODS

Among 731 patients undergoing iodine-125 low-dose-rate prostate brachytherapy (LDR-BT), SOAR was utilized in 394 patients (53.9%). Colonoscopy was performed for 97 patients (13.3%) to assess the presence, location, condition, and treatment of radiation proctitis. We also investigated treatment factors associated with the occurrence of radiation proctitis.

RESULTS

Radiation proctitis was observed in 57 patients (7.8%) and 17 (2.3%) were treated with argon plasma coagulation (APC). The incidence of radiation proctitis was 12.2% in the non-SOAR and 4.1% in the SOAR group (p < 0.001). In the non-SOAR group, the incidence of radiation proctitis was 6.6% for LDR-BT monotherapy and increased to 22.0% when combined with external beam radiation therapy (EBRT) (p = 0.001). However, in the SOAR group, these rates significantly decreased to 3.3% and 5.7% for monotherapy and combination therapy, respectively (p = 0.035, p < 0.001). With SOAR, inflammation was observed directly above the DL in most patients (87.5%), and only one patient (6.3%) required APC. The absence of SOAR (p < 0.001, HR = 0.29) and the concurrent use of EBRT (p = 0.018, HR = 2.87) were identified as significant risk factors for the occurrence of radiation proctitis.

CONCLUSION

The use of SOAR significantly reduced the incidence of radiation proctitis in patients undergoing LDR-BT monotherapy and combined EBRT. Inflammation primarily occurred directly above the DL; further examination is necessary to clarify its cause.

Recent trends in the incidence of early-onset prostate cancer

Early-onset prostate cancer (EOPC) is relatively uncommon. It is unclear if the incidence of EOPC is evolving. Utilizing data from the SEER database from 2000 to 2020, the study identified prostate cancer cases in men under 55 years, focusing on trends in annual age-adjusted incidence rates (AAIR), stage at presentation, race/ethnicity, and local treatment patterns. The study encompassed 93 071 cases of EOPC, with the median age at diagnosis being 51 years. From 2000 to 2007, the AAIR of EOPC experienced a wave-like increase from 6.9 to 8.3 per 100 000 people. It then sharply declined to 5.4 by 2014, followed by 6 years of stability, and by 2020 it had dropped to its lowest point of 4.5. The trend observed across different racial groups was consistent with the overall pattern, where non-Hispanic Black patients consistently exhibited the highest incidence and the least reduction rate (annual percent change, -1.0; 95% confidence interval, -1.8 to -0.2; P < 0.05). Stage II was the most commonly diagnosed, although its AAIR declined from 4.9 to 1.2 per 100 000 people. From 2010 through 2020, the proportion of receiving prostatectomy decreased from 63.0 to 43.6%. The declining rates of EOPC across diverse racial groups emphasize the critical need for focused research and interventions. Specifically, there is an urgent call to establish a tailored screening protocol for prostate cancer targeting Black youth.

Experimental validation of the accuracy of robotic-assisted radioactive seed implantation for tumor treatment

An experimental validation of a robotic system for radioactive iodine-125 seed implantation (RISI) in tumor treatment was conducted using customized phantom models and animal models simulating liver and lung lesions. The robotic system, consisting of planning, navigation, and implantation modules, was employed to implant dummy radioactive seeds into the models. Fiducial markers were used for target localization. In phantom experiments across 40 cases, the mean errors between planned and actual seed positions were 0.98 ± 1.05 mm, 1.14 ± 0.62 mm, and 0.90 ± 1.05 mm in the x, y, and z directions, respectively. The x, y, and z directions correspond to the left-right, anterior-posterior, and superior-inferior anatomical planes. Silicone phantoms exhibiting significantly smaller x-axis errors compared to liver and lung phantoms (p < 0.05). Template assistance significantly reduced errors in all axes (p < 0.05). No significant dosimetric deviations were observed in parameters such as D90, V100, and V150 between plans and post-implant doses (p > 0.05). In animal experiments across 23 liver and lung cases, the mean implantation errors were 1.28 ± 0.77 mm, 1.66 ± 0.69 mm, and 1.86 ± 0.93 mm in the x, y, and z directions, slightly higher than in phantoms (p < 0.05), with no significant differences between liver and lung models. The dosimetric results closely matched planned values, confirming the accuracy of the robotic system for RISI, offering new possibilities in clinical tumor treatment.

Imageable Brachytherapy with Chelator-Free Radiolabeling Hydrogel

Brachytherapy stands as an essential clinical approach for combating locally advanced tumors. Here, an injectable brachytherapy hydrogel is developed for the treatment of both local and metastatic tumor. Fe-tannins nanoparticles are efficiently and stably radiolabeled with clinical used therapeutic radionuclides (such as 131I, 90Y, 177Lu, and 225Ac) without a chelator, and then chemically cross-linked with 4-armPEG-SH to form brachytherapy hydrogel. Upon intratumoral administration, magnetic resonance imaging (MRI) signal from ferric ions embedded within the hydrogel directly correlates with the retention dosage of radionuclides, which can real-time monitor radionuclides emitting short-range rays in vivo without penetration limitation during brachytherapy. The hydrogel's design ensures the long-term tumor retention of therapeutic radionuclides, leading to the effective eradication of local tumor. Furthermore, the radiolabeled hydrogel is integrated with an adjuvant to synergize with immune checkpoint blocking therapy, thereby activating potent anti-tumor immune responses and inhibiting metastatic tumor growth. Therefore, this work presents an imageable brachytherapy hydrogel for real-time monitoring therapeutic process, and expands the indications of brachytherapy from treatment of localized tumors to metastatic tumors.

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.

Efficacy and Safety of Brachytherapy for Localized Prostate Cancer in Renal Transplant Recipients

BACKGROUND

Prostate cancer is common among male renal transplant recipients and can present challenges for medical management and patient survival. It is imperative to have a comprehensive understanding of available treatment options in this population to determine the most effective and safe therapies. Brachytherapy, a safe and effective treatment for localized prostate cancer, has not been sufficiently studied in this patient population. Therefore, this study aimed to evaluate the safety and effectiveness of brachytherapy in treating prostate cancer in renal transplant recipients.

METHODS

We retrospectively reviewed our brachytherapy database to identify patients with a previous history of renal transplantation who underwent seed implantation for localized prostate cancer. Long-term prostate-specific antigen control and treatment-related toxicity, including graft dysfunction and urinary and rectal complications, were assessed and compared with published outcomes. Results were analyzed to evaluate the efficacy and safety of seed implantation in this patient population.

RESULTS

We identified 2 patients with previous renal transplantation who underwent permanent seed implantation for localized prostate cancer. Follow-ups ranged from 53 to 57 months, and both patients remained free of prostate-specific antigen progression with normal graft function. No acute and late complications occurred.

CONCLUSION

Brachytherapy is a safe and effective treatment option for post-renal transplant prostate cancer. Given the paucity of reports on brachytherapy in this population, the findings of this study, despite a small sample size, contribute to the increasing body of evidence supporting the use of brachytherapy in this patient population.

Review of brachytherapy clinical trials: a cross-sectional analysis of ClinicalTrials.gov

INTRODUCTION

Characterizing the landscape of clinical trials including brachytherapy can provide an overview of the current status and research trends which may guide further areas of investigation.

METHOD

We queried 449,849 clinical trials from the ClinicalTrials.gov registry using brachytherapy-related keywords from 1980 to 2023, yielding 245 multi-arm and 201 single-arm, brachytherapy trials. Multi-arm and single-arm brachytherapy trials were compared using 12 trial protocol elements.

RESULTS

The number of trials including brachytherapy has increased over time, with over 60% of trials registered in 2010 onwards. The majority of clinical trials were Phase 2 or 3, evaluated both safety and efficacy, and were funded by academic sponsors. The most common tumor sites evaluated in brachytherapy clinical trials include prostate, cervix, liver, endometrium, and breast.

CONCLUSION

There remains continued interest in clinical trials including brachytherapy focused on evaluation of novel delivery systems, treatment planning, and new indications. More brachytherapy clinical trials are needed to define the optimal clinical utilization and advance prospective research in this field.

Cancer Brachytherapy at the Nanoscale: An Emerging Paradigm

Brachytherapy is an established treatment modality that has been globally utilized for the therapy of malignant solid tumors. However, classic therapeutic sealed sources used in brachytherapy must be surgically implanted directly into the tumor site and removed after the requisite period of treatment. In order to avoid the trauma involved in the surgical procedures and prevent undesirable radioactive distribution at the cancerous site, well-dispersed radiolabeled nanomaterials are now being explored for brachytherapy applications. This emerging field has been coined "nanoscale brachytherapy". Despite present-day advancements, an ongoing challenge is obtaining an advanced, functional nanomaterial that concurrently incorporates features of high radiolabeling yield, short labeling time, good radiolabeling stability, and long tumor retention time without leakage of radioactivity to the nontargeted organs. Further, attachment of suitable targeting ligands to the nanoplatforms would widen the nanoscale brachytherapy approach to tumors expressing various phenotypes. Molecular imaging using radiolabeled nanoplatforms enables noninvasive visualization of cellular functions and biological processes in vivo. In vivo imaging also aids in visualizing the localization and retention of the radiolabeled nanoplatforms at the tumor site for the requisite time period to render safe and effective therapy. Herein, we review the advancements over the last several years in the synthesis and use of functionalized radiolabeled nanoplatforms as a noninvasive substitute to standard brachytherapy sources. The limitations of present-day brachytherapy sealed sources are analyzed, while highlighting the advantages of using radiolabeled nanoparticles (NPs) for this purpose. The recent progress in the development of different radiolabeling methods, delivery techniques and nanoparticle internalization mechanisms are discussed. The preclinical studies performed to date are summarized with an emphasis on the current challenges toward the future translation of nanoscale brachytherapy in routine clinical practices.

Stimuli-Responsive Nanoradiosensitizers for Enhanced Cancer Radiotherapy

Radiotherapy (RT) has been a classical therapeutic method of cancer for several decades. It attracts tremendous attention for the precise and efficient treatment of local tumors with stimuli-responsive nanomaterials, which enhance RT. However, there are few systematic reviews summarizing the newly emerging stimuli-responsive mechanisms and strategies used for tumor radio-sensitization. Hence, this review provides a comprehensive overview of recently reported studies on stimuli-responsive nanomaterials for radio-sensitization. It includes four different approaches for sensitized RT, namely endogenous response, exogenous response, dual stimuli-response, and multi stimuli-response. Endogenous response involves various stimuli such as pH, hypoxia, GSH, and reactive oxygen species (ROS), and enzymes. On the other hand, exogenous response encompasses X-ray, light, and ultrasound. Dual stimuli-response combines pH/enzyme, pH/ultrasound, and ROS/light. Lastly, multi stimuli-response involves the combination of pH/ROS/GSH and X-ray/ROS/GSH. By elaborating on these responsive mechanisms and applying them to clinical RT diagnosis and treatment, these methods can enhance radiosensitive efficiency and minimize damage to surrounding normal tissues. Finally, this review discusses the additional challenges and perspectives related to stimuli-responsive nanomaterials for tumor radio-sensitization.

Current status and future readiness of Indian radiation oncologists to embrace prostate high-dose-rate brachytherapy: An Indian Brachytherapy Society survey

Purpose

This survey aimed to understand the practice pattern and attitude of Indian doctors towards prostate brachytherapy.

Material and methods

A 21-point questionnaire was designed in Google form and sent to radiation oncologists practicing in India, using texts, mails, and social media. Responses were collated, and descriptive statistical analysis was performed.

Results

A total of 212 radiation oncologists from 136 centers responded to the survey questionnaire, with majority (66%) being post-specialty training > 6 years. We found that about 44.3% (n = 94) of respondents do not practice interstitial brachytherapy for any site, and majority (83.3%, n = 175) do not practice high-dose-rate (HDR) prostate brachytherapy. Only 2.8% (n = 6) of doctors preferred boost by brachytherapy compared with 38.1% (n = 80) of respondents, who favored stereotactic body radiation therapy (SBRT) boost. When asked about the indication of HDR prostate brachytherapy in Indian setting, 32.5% (n = 67) of respondents favored monotherapy, 46.1% (n = 95) of oncologists thought boost as a good indication, and 21.4% (n = 44) preferred re-irradiation/salvage setting. The most cited reason for prostate brachytherapy not being popularly practiced in India was lack of training (84.8%, n = 179). It was also noted that out of 80 respondents who practiced SBRT for prostate boost, 37 would prefer HDR brachytherapy boost if given adequate training and facilities.

Conclusions

The present survey provided insight on practice of prostate brachytherapy in India. It is evident that majority of radiation oncologists do not practice HDR prostate brachytherapy due to lack of training and infrastructure. Indian physicians are willing to learn and start prostate brachytherapy procedures if dedicated training and workshops are organized.

Patients with PSA below 0.2 ng/mL at 8 years post high-dose-rate brachytherapy have an extremely low risk of subsequent recurrence

OBJECTIVES

We have analyzed the long-term follow-up data of patients with prostate cancer (PCa) who underwent high-dose-rate brachytherapy (HDR-BT) and external beam radiotherapy (EBRT) combined with long-term androgen deprivation therapy (ADT). The objective was to determine the optimal time for cessation of PSA monitoring after HDR-BT.

METHODS

We included 309 patients with clinical stage T1c-T4 N0-1 M0 PCa who received HDR-BT and EBRT combined with long-term ADT between 2005 and 2018. We stratified the patients based on their prostate-specific antigen (PSA) levels and identified the factors associated with biochemical recurrence (BCR) and clinical progression (CP).

RESULTS

The median follow-up duration was 98 months (range: 31-207 months). Among the 306 patients, 76 developed BCR and 47 developed CP subsequently. We found that the PSA levels at 3, 5, and 8 years significantly correlated with the oncological outcomes of brachytherapy. No patient with a PSA level ≤ 0.2 ng/mL at 8 years later developed BCR or CP.

CONCLUSION

Our long-term data suggest that in the presence of a PSA level ≤ 0.2 ng/mL at 8 years later, PSA monitoring may be safely discontinued due to the extremely low risk of subsequent oncological events. The data presented in this study will assist clinicians in determining the optimal management strategy for patients with PCa following HDR-BT and EBRT combined with long-term ADT.

Prognostic value of pretreatment FDG PET-CT for short-term efficacy of radioactive iodine-125 seed implantation in patients with NSCLC

PURPOSE

To analyze the short-term clinical response of radioactive iodine-125 seed implantation (I125-SI) in patients of non-small-cell lung cancer (NSCLC) and explore possible correlations of various metabolic parameters of pretreatment FDG PET-CT with the short-term efficacy of this treatment modality.

METHODS AND MATERIALS

The present study is a retrospective analysis of treatment records of 46 NSCLC patients who were treated with I125-SI for lung tumors in Tianjin First Central Hospital from January 2016 to December 2018. The correlation among parameters D90, gender, pathological pattern, age, maximum tumor diameter, Metabolic Tumor Volume (MTV), SUVmax, SUVpeak, SUVmean, Total Lesion Glycolysis (TLG), High metabolic tumor cell ratio (HMR) and Carcinoembryonic antigen(CEA)with short-term efficacy of I125-SI was analyzed by two independent-sample t-test, Mann-Whitney U test or Chi-squared test and binary logistic regression.

RESULTS

After uneventful completion of treatment, patients were followed up at regular intervals. At the first month followup, none of cases showed complete response (CR), while 4 cases showed partial response (PR). After 3 months, there were 2 cases of CR, and 25 cases of PR; after 6 months, there were 5 cases of CR, and 27 cases of PR. D90 (p= 0.028, OR:1.075, 95% CI:1.008-1.147), MTV (p= 0.026, OR: 0.918, 95% CI: 0.851-0.990), HMR (p= 0.020, OR: 0.003, 95% CI: 0-0.407) were independent predictors for the short-term efficacy. The predictive accuracy of MTV was medium (AUC = 0.781; cutoff value = 44.58). However, the predictive accuracies of D90 and HMR were low, with the values of AUC being 0.650 for both the parameters, and their cutoff values being 127.8 Gy and 0.27 respectively.

CONCLUSIONS

I125-SI is an effective therapy with few complications in NSCLC patients. Small MTV, high D90 and low HRM were found to be linked with better local control at 6 months postimplantation.

Population-based patient-reported quality of life outcomes following low-dose-rate versus high-dose-rate brachytherapy monotherapy for low-intermediate risk prostate cancer

INTRODUCTION

To evaluate patient reported quality of life outcomes (QoL) following low-dose-rate brachytherapy (LDR-BT) and high-dose-rate brachytherapy (HDR-BT) monotherapy for prostate cancer at a population-based setting.

METHODS

The study comprised men with low-intermediate risk prostate cancer in the Prostate Cancer Outcomes Registry Victoria (PCOR-Vic), who were treated with LDR-BT or HDR-BT monotherapy between 2015 and 2020 and completed the Expanded Prostate Cancer Index Composite (EPIC-26) questionnaire 12-month post-treatment. Men who had ADT were excluded (n = 12). Differences in substantial symptoms (i.e. 'moderate' or 'big' problem on a 5-point Likert scale) between LDR-BT and HDR-BT arms were evaluated using Pearson's chi-squared test. Multivariable linear regressions were used to estimate differences in EPIC-26 urinary, bowel and sexual functional domain scores between LDR-BT and HDR-BT arms.

RESULTS

Overall, 198 men were included in this study, of which 167 (84%) had LDR-BT and 31 (16%) had HDR-BT. 9 (4.6%), 10 (5.1%) and 56 (28%) reported substantial symptoms for overall urinary, bowel and sexual function at 12-month post-treatment, with no significant difference between LDR-BT and HDR-BT arms. The adjusted mean differences in urinary incontinence, urinary obstructive, bowel and sexual function domain scores between LDR-BT and HDT-BT were: -3.53 (-8.21 to 1.14), -1.27 (-6.88 to 4.35), -0.01 (-5.63 to 5.63) and -8.68 (-21.44 to 4.07) respectively - these were not statistically significant and did not meet the minimal clinically important difference.

CONCLUSION

This is the first Australian population-based study comparing QoL in men who had LDR-BT and HDR-BT, with no statistically or clinically significant differences in QoL observed at 12-month post-treatment.

High-dose-rate brachytherapy as monotherapy versus as boost in unfavorable intermediate-risk localized prostate cancer: A matched-pair analysis

PURPOSE

High-dose-rate brachytherapy as monotherapy (HDR-M), or as a boost combined with external beam radiotherapy (HDR-B), are both suitable treatments for intermediate-risk prostate cancer. However, data directly comparing these two approaches for men with unfavorable intermediate-risk (UIR) patients are lacking.

METHODS AND MATERIALS

Patients with NCCN-defined UIR prostate cancer treated from 1997 to 2020 were identified in a prospectively maintained, single institution database. HDR-M and HDR-B patients were matched using three factors: age ±3 years; Gleason score (major and minor); and clinical T stage. Biochemical failure was defined as PSA nadir (nPSA) + 2. Available acute and chronic toxicities are additionally reported.

RESULTS

A total of 247 patients were identified (170 receiving HDR-B, 77 receiving HDR-M), ultimately yielding 70 matched pairs (140 patients) for inclusion. The median followup time was 5.2 years for HDR-M compared with 9.3 years for HDR-B (p < 0.001). The two cohorts had similar calculated prostate EQD2 (HDR-B 118 Gy vs. HDR-M 115 Gy, p = 0.977). No significant differences in OS, CSS, DM, LRR, or FFBF were identified. HDR-B had an increased rate of any acute grade 2+ gastrointestinal toxicity and worse acute dysuria and diarrhea. Chronic gastrointestinal and genitourinary toxicity was similar.

CONCLUSIONS

These data suggest that HDR brachytherapy as monotherapy is an effective treatment option for selected patients with unfavorable intermediate-risk prostate cancer and provides a more favorable gastrointestinal toxicity profile than HDR-B. Prospective trials should be conducted to refine the selection process for this heterogeneous cohort of patients.

The Current Trend of Radiation Therapy for Patients with Localized Prostate Cancer

A recent approach to radiotherapy for prostate cancer is the administration of high doses of radiation to the prostate while minimizing the risk of side effects. Thus, image-guided radiotherapy utilizes advanced imaging techniques and is a feasible strategy for increasing the radiation dose. New radioactive particles are another approach to achieving high doses and safe procedures. Prostate brachytherapy is currently considered as a combination therapy. Spacers are useful to protect adjacent organs, specifically the rectum, from excessive radiation exposure.

Innate Immune System in the Context of Radiation Therapy for Cancer

Radiation therapy (RT) remains an integral component of modern oncology care, with most cancer patients receiving radiation as a part of their treatment plan. The main goal of ionizing RT is to control the local tumor burden by inducing DNA damage and apoptosis within the tumor cells. The advancement in RT, including intensity-modulated RT (IMRT), stereotactic body RT (SBRT), image-guided RT, and proton therapy, have increased the efficacy of RT, equipping clinicians with techniques to ensure precise and safe administration of radiation doses to tumor cells. In this review, we present the technological advancement in various types of RT methods and highlight their clinical utility and associated limitations. This review provides insights into how RT modulates innate immune signaling and the key players involved in modulating innate immune responses, which have not been well documented earlier. Apoptosis of cancer cells following RT triggers immune systems that contribute to the eradication of tumors through innate and adoptive immunity. The innate immune system consists of various cell types, including macrophages, dendritic cells, and natural killer cells, which serve as key mediators of innate immunity in response to RT. This review will concentrate on the significance of the innate myeloid and lymphoid lineages in anti-tumorigenic processes triggered by RT. Furthermore, we will explore essential strategies to enhance RT efficacy. This review can serve as a platform for researchers to comprehend the clinical application and limitations of various RT methods and provides insights into how RT modulates innate immune signaling.

Efficacy of focal high-dose-rate brachytherapy in the treatment of patients diagnosed with low or favourable: intermediate-risk prostate cancer-a protocol for a randomised controlled trial

INTRODUCTION

Prostate cancer (PCa) is men's second most predominant cancer worldwide. Because the prostate-specific antigen test is used in diagnostics, PCa is more often diagnosed in the early stages, making radical treatment of the disease possible. However, it is estimated that over a million men worldwide suffer from radical treatment-related complications. Thus, focal treatment has been proposed as a solution, which aims to destroy the predominant lesson that determines the progression of the disease. The main objective of our study is to compare the quality of life and efficacy of patients diagnosed with PCa before and after the treatment with focal high-dose-rate brachytherapy and to compare results with focal low-dose-rate brachytherapy and active surveillance.

METHODS AND ANALYSIS

150 patients diagnosed with low-risk or favourable intermediate-risk PCa who meet the inclusion criteria will be enrolled in the study. Patients are going to be randomly assigned to the study groups: focal high-dose-rate brachytherapy (group 1), focal low-dose-rate brachytherapy (group 2) and active surveillance (group 3). The study's primary outcomes are quality of life after the procedure and time without biochemical disease recurrence. The secondary outcomes are early and late genitourinary and gastrointestinal reactions after the focal high-dose and low-dose-rate brachytherapies and evaluation of the importance and significance of in vivo dosimetry used for high-dose-rate brachytherapy.

ETHICS AND DISSEMINATION

Bioethics committee approval was obtained before this study. The trial results will be published in peer-reviewed journals and at conferences.

TRIAL REGISTRATION NUMBER

Vilnius regional bioethics committee; approval ID 2022/6-1438-911.

Validation of the bladder neck as an important organ at risk in prostate seed brachytherapy based on D2cc: A single-institution, retrospective review

Purpose

International guidelines recommend urethral dose volume constraints to minimize the risk of urinary toxicity after prostate brachytherapy. An association between dose to the bladder neck (BN) and toxicity has previously been reported, and we sought to evaluate the impact of this organ at risk on urinary toxicity, based on intra-operative contouring.

Material and methods

Rates of acute and late urinary toxicity (AUT and LUT, respectively) were graded according to CTCAE version 5.0 for 209 consecutive patients who underwent low-dose-rate (LDR) brachytherapy monotherapy, with approximately equal numbers treated before and after we began routinely contouring the BN. AUT and LUT were compared in patients treated before and after we began contouring the OAR, and also for those treated after we began contouring who had a D2cc of greater than or less than 50% prescription dose.

Results

AUT and LUT fell after intra-operative BN contouring was instituted. Rates of grade ≥ 2 AUT fell from 15/101 (15%) to 9/104 (8.6%), p = 0.245. Grade ≥ 2 LUT decreased from 32/100 (32%) to 18/100 (18%), p = 0.034. Grade ≥ 2 AUT was observed in 4/63 (6.3%) and 5/34 (15%) of those with a BN D2cc >/≤ 50%, respectively, of prescription dose. Corresponding rates for LUT were 11/62 (18%) and 5/32 (16%).

Conclusions

There were lower urinary toxicity rates for patients treated after we commenced routine intra-operative contouring of the BN. No clear relationship was observed between dosimetry and toxicity in our population.

Treatment planning comparison of high-dose-rate brachytherapy vs. robotic and conventional stereotactic body radiotherapy for ultrahypofractionated treatment of prostate cancer

Background and purpose

Ultrahypofractionated radiation therapy is increasingly used in the treatment of prostate cancer. High-dose-rate brachytherapy (HDR-BT) and stereotactic body radiotherapy (SBRT) are representative methods of ultrahypofractionation. This study was performed to compare clinically applied treatment plans for patients who had been treated using HDR-BT vs. conventional or robotic SBRT.

Materials and methods

Calculated dose-volume indices between HDR-BT without a perirectal spacer (n = 20), robotic SBRT without a spacer (n = 40), and conventional (non-robotic) SBRT with a spacer (n = 40) were compared. Percentages against the prescription dose regarding the planning target volume (PTV), bladder, rectum, and urethra were statistically compared.

Results

The D50% of the PTV with HDR-BT (140.5% ± 4.9%) was significantly higher than that with robotic or conventional SBRT (116.2% ± 1.6%, 101.0% ± 0.4%, p < 0.01). The D2cm³ of the bladder with HDR-BT (65.6% ± 6.4%) was significantly lower than those with SBRT (105.3% ± 2.9%, 98.0% ± 1.3%, p < 0.01). The D2cm³ of the rectum with HDR-BT (60.6% ± 6.2%) was also significantly lower than those with SBRT (85.1% ± 8.8%, 70.4% ± 9.6%, p < 0.01). By contrast, the D0.1cm³ of the urethra with HDR-BT (117.1% ± 3.6%) was significantly higher than those with SBRT (100.2% ± 0.7%, 104.5% ± 0.6%, p < 0.01).

Conclusions

HDR-BT could administer a higher dose to the PTV and a lower dose to the bladder and rectum, at the cost of a slightly higher dose to the urethra compared with SBRT.

HoloLens augmented reality system for transperineal free-hand prostate procedures

Purpose

An augmented reality (AR) system was developed to facilitate free-hand real-time needle guidance for transperineal prostate (TP) procedures and to overcome the limitations of a traditional guidance grid.

Approach

The HoloLens AR system enables the superimposition of annotated anatomy derived from preprocedural volumetric images onto a patient and addresses the most challenging part of free-hand TP procedures by providing real-time needle tip localization and needle depth visualization during insertion. The AR system accuracy, or the image overlay accuracy ( n = 56 ), and needle targeting accuracy ( n = 24 ) were evaluated within a 3D-printed phantom. Three operators each used a planned-path guidance method ( n = 4 ) and free-hand guidance ( n = 4 ) to guide needles into targets in a gel phantom. Placement error was recorded. The feasibility of the system was further evaluated by delivering soft tissue markers into tumors of an anthropomorphic pelvic phantom via the perineum.

Results

The image overlay error was 1.29 ± 0.57    mm , and needle targeting error was 2.13 ± 0.52    mm . The planned-path guidance placements showed similar error compared to the free-hand guidance ( 4.14 ± 1.08    mm versus 4.20 ± 1.08    mm , p = 0.90 ). The markers were successfully implanted either into or in close proximity to the target lesion.

Conclusions

The HoloLens AR system can provide accurate needle guidance for TP interventions. AR support for free-hand lesion targeting is feasible and may provide more flexibility than grid-based methods, due to the real-time 3D and immersive experience during free-hand TP procedures.

A Contemporary Report of Low-Dose-Rate Brachytherapy for Prostate Cancer Using MRI for Risk Stratification: Disease Outcomes and Patient-Reported Quality of Life

PURPOSE

We examined a prospective consecutive cohort of low dose rate (LDR) brachytherapy for prostate cancer to evaluate the efficacy of monotherapy for unfavorable-intermediate risk (UIR) disease, and explore factors associated with toxicity and quality of life (QOL).

METHODS

149 men with prostate cancer, including 114 staged with MRI, received Iodine-125 brachytherapy alone (144-145 Gy) or following external beam radiation therapy (110 Gy; EBRT). Patient-reported QOL was assessed by the Expanded Prostate Index Composite (EPIC) survey, and genitourinary (GU) and gastrointestinal (GI) toxicity were prospectively recorded (CTC v4.0). Global QOL scores were assessed for decline greater than the minimum clinically important difference (MCID). Univariate analysis (UVA) was performed, with 30-day post-implant dosimetry covariates stratified into quartiles. Median follow-up was 63 mo.

RESULTS

Men with NCCN low (n = 42) or favorable-intermediate risk (n = 37) disease were treated with brachytherapy alone, while most with high-risk disease had combined EBRT (n = 17 of 18). Men with UIR disease (n = 52) were selected for monotherapy (n = 42) based on clinical factors and MRI findings. Freedom from biochemical failure-7 yr was 98%. Of 37 men with MRI treated with monotherapy for UIR disease, all 36 men without extraprostatic extension were controlled. Late Grade 2+/3+ toxicity occurred in 55/3% for GU and 8/2% for GI, respectively. Fifty men were sexually active at baseline and had 2 yr sexual data; 37 (74%) remained active at 2 yr. Global scores for urinary incontinence (UC), urinary irritation/obstruction (UIO), bowel function, and sexual function (SF) showed decreases greater than the MCID (p < 0.05) in UC at 2 mo, UIO at 2 and 6 mo, and SF at 2-24 mo, and >5 yr. Analysis did not reveal any significant associations with any examined rectal or urethral dosimetry for late toxicity or QOL.

CONCLUSION

Disease outcomes and patient-reported QOL support LDR brachytherapy, including monotherapy for UIR disease.

Improving Radiotherapy Response in the Treatment of Head and Neck Cancer

The application of radiotherapy to the treatment of cancer has existed for over 100 years. Although its use has cured many, much work remains to be done to minimize side effects, and in-field tumor recurrences. Resistance of the tumor to a radiation-mediated death remains a complex issue that results in local recurrence and significantly decreases patient survival. Here, we review mechanisms of radioresistance and selective treatment combinations that improve the efficacy of the radiation that is delivered. Further investigation into the underlying mechanisms of radiation resistance is warranted to develop not just novel treatments, but treatments with improved safety profiles relative to current radiosensitizers. This review is written in memory and honor of Dr. Peter Stambrook, an avid scientist and thought leader in the field of DNA damage and carcinogenesis, and a mentor and advocate for countless students and faculty.

Commercial and business aspects of alpha radioligand therapeutics

Radioligand therapy (RLT) is gaining traction as a safe and effective targeted approach for the treatment of many cancer types, reflected by a substantial and growing commercial market (valued at $7.78 billion in 2021, with a projected value of $13.07 billion by 2030). Beta-emitting RLTs have a long history of clinical success dating back to the approval of Zevalin and Bexxar in the early 2000s, later followed by Lutathera and Pluvicto. Alpha radioligand therapeutics (ARTs) offer the potential for even greater success. Driven by ground-breaking clinical results in early trials, improved isotope availability, and better understanding of isotope and disease characteristics, the global market for alpha emitters was estimated at $672.3 million for the year 2020, with projected growth to $5.2 billion by 2027. New company formations, promising clinical trial data, and progression for many radioligand therapy products, as well as an inflow of investor capital, are contributing to this expanding field. Future growth will be fueled by further efficacy and safety data from ART clinical trials and real-world results, but challenges remain. Radionuclide supply, manufacturing, and distribution are key obstacles for growth of the field. New models of delivery are needed, along with cross-disciplinary training of specialized practitioners, to ensure patient access and avoid challenges faced by early RLT candidates such as Zevalin and Bexxar. Understanding of the history of radiation medicine is critical to inform what may be important to the success of ART-most past projections were inaccurate and it is important to analyze the reasons for this. Practical considerations in how radiation medicine is delivered and administered are important to understand in order to inform future approaches.

Hypofractionation as a solution to radiotherapy access in latin america: expert perspective

Background

Limited radiation therapy resources have resulted in an interest in developing time and cost-saving innovations to expand access to cancer treatment, in Latin America. Therefore, hypofractionated radiotherapy (HRT) is a possible solution, as this modality delivers radiation over a shorter period of time.

Materials and methods

A selected panel of Latin American (LA) experts in fields related to HRT were provided with a series of relevant questions to address, prior to the multi-day conference. Within this meeting, each narrative was discussed and edited, through numerous rounds of discussion, until agreement was achieved.

Results

The challenges identified in increasing the adoption of HRT in LA include a lack of national and regional clinical practice guidelines and cancer registries; a lack of qualified human resources and personnel education; high up-front costs of equipment; disparate resource distribution and scarce HRT research. An analysis for these overarching challenges was developed and answered with recommendations.

Conclusion

Extending the adoption of HRT in LA can provide a path forward to increase access to radiotherapy and overcome the shortage of equipment. HRT has the potential to improve population health outcomes and patient centered care, while offering comparable local control, toxicity, palliation, and late effects for multiple indications, when compared to conventional RT. Concerted efforts from all involved stakeholders are needed to overcome the barriers in adopting this strategy in LA countries. The recommendations presented in this article can serve as a plan of action for HRT adoption in other countries in a similar situation.

Global optimization for spot-based treatment planning

PURPOSE

Many radiotherapy modalities can deliver concentrated radiation in the form of spots, such as Gamma Knife (GK), GammaPod (GP), intensity-modulated proton therapy, and brachytherapy, and can be generalized as spot-based treatments. These treatments have a great therapeutic advantage of creating potent target dose while sparing the surrounding normal tissues. However, global optimization to determine the spot positions, shapes, and intensities is an intractable combinatorial problem for any real 3D problem. The conventional approach adopts heuristic spot selection and intensity optimization in a sequential manner to mitigate the problem complexity. In this work, we propose a novel framework that enables global optimization of spot-based treatment planning.

METHODS

The framework is based on kernel decomposition (KD) dose calculation, which models each spot dose as a scaled shift-invariant kernel, with the reference kernels and scales pre-calculated. During optimization, the framework incorporates Fast Fourier Transform (FFT) for objective and derivative evaluations and accommodates all spot candidates in optimization search with a temporal complexity of O(N3 log N) as opposed to O(N6 ) complexity in the conventional beamlet framework for volume dimensions of N × N × N. We demonstrated the FFT framework using simulations with different objectives. The framework's planning performance was illustrated using clinical GK and GP cases.

RESULTS

Pre-processing involves only a small number of reference kernels and a scale map for the KD model with marginal spatial and temporal overheads. For simulations with 512 × 512 image dimensions, plan optimization finished in ∼2 seconds with FFT, whereas it took 100× longer with the beamlet approach. For clinical cases, the FFT attained solutions within a minute with improved plan quality compared to clinical plans: better conformity and less integral dose because of using a global fine search space for optimal spots.

CONCLUSIONS

The scaled shift-invariance and FFT framework opens a new paradigm for spot-based treatment planning, as it can substantially reduce both the spatial and temporal complexities. The framework makes global optimization for spot-based treatment planning clinically feasible.

Mucinous adenocarcinoma of the prostatic urethra after brachytherapy for prostatic adenocarcinoma: a case series

Mucinous adenocarcinoma of the urethra is extremely rare, even more so in a setting of postradiation therapy, with only 3 cases reported up to date including the first case published by our group in 2011. In the present study, we included the long-term follow-up on our previously reported case and report 3 additional cases. This is the first case series to date of this rare disease entity. The aim of this study is to review the clinicopathologic features of mucinous adenocarcinoma of the prostatic urethra in patients after receiving brachytherapy for prostatic adenocarcinoma. We identified 4 patients with a mean age of 72 years, and a mean interval of 14.8 years from brachytherapy for prostate carcinoma (grade group 1). Patients presented with hematuria or urinary retention. A colonoscopy was performed in three-fourth of patients and was within normal limits. Three patients underwent cystoprostatectomy and 1 had a transurethral resection of the prostate. On gross examination, only tumor formed a 3.5 cm tan-gray, ulcerated, friable, and necrotic mass and 2 displayed either irregular red granular or thickened areas within the prostatic urethra. Abundant extracellular mucin pools dissecting the prostatic stroma were present in all tumors, with clusters of tumor cells floating in the mucin. The mucin pools were lined by pleomorphic pseudostratified columnar mucinous epithelium. Tumors were diffusely positive for CK20, CDX2 (4/4), and AMACR (2/2); they focally expressed CK7 (2/4), and lacked nuclear β-catenin expression (3/3). PSA, PSAP, NKX3.1, p63, and GATA3 were negative in the tumors tested. Among the 3 patients who underwent radical surgery, 2 had stage 2 tumors (confined to the prostatic urethra and prostate), and 1 had a stage 3 tumor, with seminal vesicle involvement. All 4 patients were alive without disease with a mean follow-up of 4.9 years. In conclusion, brachytherapy-associated mucinous adenocarcinoma of the prostatic urethra displays intestinal-type features as its non-radiation-related counterpart. It appears to lack a villous adenoma component, displays a different immunohistochemical profile with diffuse CK20 and CDX2 positivity, and is associated with lower stage and less aggressive behavior.

Bone Health Management in the Continuum of Prostate Cancer Disease

Prostate cancer (PCa) is the second-leading cause of cancer-related deaths in men. PCa cells require androgen receptor (AR) signaling for their growth and survival. Androgen deprivation therapy (ADT) is the preferred treatment for patients with locally advanced and metastatic PCa disease. Despite their initial response to androgen blockade, most patients eventually will develop metastatic castration-resistant prostate cancer (mCRPC). Bone metastases are common in men with mCRPC, occurring in 30% of patients within 2 years of castration resistance and in >90% of patients over the course of the disease. Patients with mCRPC-induced bone metastasis develop lesions throughout their skeleton; the 5-year survival rate for these patients is 47%. Bone-metastasis-induced early changes in the bone that proceed the osteoblastic response in the bone matrix are monitored and detected via modern magnetic resonance and PET/CT imaging technologies. Various treatment options, such as targeting osteolytic metastasis with bisphosphonates, prednisone, dexamethasone, denosumab, immunotherapy, external beam radiation therapy, radiopharmaceuticals, surgery, and pain medications are employed to treat prostate-cancer-induced bone metastasis and manage bone health. However, these diagnostics and treatment options are not very accurate nor efficient enough to treat bone metastases and manage bone health. In this review, we present the pathogenesis of PCa-induced bone metastasis, its deleterious impacts on vital organs, the impact of metastatic PCa on bone health, treatment interventions for bone metastasis and management of bone- and skeletal-related events, and possible current and future therapeutic options for bone management in the continuum of prostate cancer disease.

Prostate cancer: understanding patients' treatment options

Prostate cancer is the most common cancer among men in the UK. It is a disease with no specific preventable risk factors, no specific signs and symptoms, and a significant health burden. This article explains the various treatment options available for patients with prostate cancer, with the aim of assisting nurses in supporting person-centred decision-making. It also discusses the risk factors, signs and symptoms, diagnosis, staging, grading and risk stratification of prostate cancer.

Investigation the effect of a magnetic field on the dose distribution of I-125, Ir-192, Yb-169, and Co-60 brachytherapy sources by Monte Carlo simulation

Magnetic resonance imaging (MRI) during brachytherapy may alter the dose distribution of radioactive sources implanted in the tumor. This study investigates the impact of a magnetic field of 1.5 T, 3 T, and 7 T strengths on the dose distribution of high dose rate Co-60, Ir-192, and Yb-169, and low dose rate I-125 sources, using Geant4 Monte Carlo toolkit. After validating the simulation results by calculating the AAPM-TG43 dosimetric parameters, seven sources of each radioisotope were simulated in a water phantom, and their dose distributions were compared under the influence of a magnetic field. The simulation results indicate that using Co-60 brachytherapy under the MRI guidance is not recommended. Furthermore, the impact of a magnetic field of up to 7 T strength on the dose distribution of Ir-192, Yb-169, and I-125 sources is negligible, provided that there is no air pocket near brachytherapy sources.

Insights and Strategies to Revive Brachytherapy Using Social Media: A Google Trends Analysis

Introduction: The utilization and public awareness of brachytherapy are both declining. Social media has an increasing presence in health promotions. As regards cancer care, social media has been successfully used as a platform for information dissemination, psychosocial support, and patient engagement and empowerment.

Methods and materials: Using Google Trends (Google LLC, Mountain View, CA, USA), we analyzed the impacts on the public interest of three brachytherapy-related social media campaigns/publicity events and compared and contrasted them with three other campaigns/publicity events. We used descriptive statistics (mean ± standard deviation (SD)) to describe the search results, independent t-tests to compare means before and after campaigns/announcements for short-term effects, and one-way ANOVA (or Kruskal-Wallis test when appropriate) to compare mean values across distinct time periods for long-term effects.

Results: We identified three major types of social media campaigns/events: those that have a short-term impact but little long-term impact, those that have both short-term and long-term impacts, and those with little short-term or long-term impact. We examined campaigns with significant and lasting impacts and noticed that they tend to be celebrity-related/celebrity-endorsed, focused on sharing personal experiences, and occur with regular frequency.

Conclusions: To increase public awareness of brachytherapy, the American Brachytherapy Society (ABS) can consider tie-ins with events and people with high search traffic (such as Breast Cancer Awareness Month), having celebrities/influencers who were treated with brachytherapy to provide testimonials, encouraging patient engagement and sharing of their experiences with brachytherapy on social media, and setting up recurring brachytherapy publicity events.

Implementation of High-Dose-Rate, CT-Based Prostate Brachytherapy in an Academic Teaching Hospital and Residency Training Program

Introduction

Prostate brachytherapy provides the most durable local control for prostate adenocarcinoma among all radiation treatment options. However, likely due to decreased trainee familiarity with the technique and resource intensity, it has seen a decline in utilization. Here we outline our experience with starting a high-dose-rate (HDR) prostate brachytherapy program within a residency training program and present our outcome data.

Methods

Patients were identified and screened using clinical data and volume study for candidacy for brachytherapy implantation. Eligible candidates were implanted and subsequently had radiation planning and delivery in our clinic. Descriptive statistical analysis was performed on our outcomes and dosimetry data and presented in tabular form.

Results

Seventeen patients were treated for a total of 18 implants (one monotherapy). No implant was aborted. No acute urinary retention requiring catheterization or chronic urethral stricture occurred. Biochemical recurrence-free survival was 94% at a median follow-up of 28.5 months (range 8.2-50 months); the one failure occurred in a very high-risk patient at 37 months following treatment. Dosimetrically, prostate coverage, urethra sparing, and rectum sparing aims were met. Volumetric bladder aims were also met; however, the max point dose to the bladder neck was above the guideline.

Conclusion

Our department successfully implemented an HDR prostate brachytherapy program. Treatments were effective and there was no grade 3 toxicity to report.

Radiotherapy as a tool to elicit clinically actionable signalling pathways in cancer

A variety of targeted anticancer agents have been successfully introduced into clinical practice, largely reflecting their ability to inhibit specific molecular alterations that are required for disease progression. However, not all malignant cells rely on such alterations to survive, proliferate, disseminate and/or evade anticancer immunity, implying that many tumours are intrinsically resistant to targeted therapies. Radiotherapy is well known for its ability to activate cytotoxic signalling pathways that ultimately promote the death of cancer cells, as well as numerous cytoprotective mechanisms that are elicited by cellular damage. Importantly, many cytoprotective mechanisms elicited by radiotherapy can be abrogated by targeted anticancer agents, suggesting that radiotherapy could be harnessed to enhance the clinical efficacy of these drugs. In this Review, we discuss preclinical and clinical data that introduce radiotherapy as a tool to elicit or amplify clinically actionable signalling pathways in patients with cancer.

Network models of prostate cancer immune microenvironments identify ROMO1 as heterogeneity and prognostic marker

Prostate cancer (PCa) is the fifth leading cause of death from cancer in men worldwide. Its treatment remains challenging due to the heterogeneity of the tumor, mainly because of the lack of effective and targeted prognostic markers at the system biology level. First, the data were retrieved from TCGA dataset, and valid samples were obtained by consistent clustering and principal component analysis; next, key genes were analyzed for prognosis of PCa using WGCNA, MEGENA, and LASSO Cox regression model analysis, while key genes were screened based on disease-free survival significance. Finally, TIMER data were selected to explore the relationship between genes and tumor immune infiltration, and GSCAlite was used to explore the small-molecule targeted drugs that act with them. Here, we used tumor subtype analysis and an energetic co-expression network algorithm of WGCNA and MEGENA to identify a signal dominated by the ROMO1 to predict PCa prognosis. Cox regression analysis of ROMO1 was an independent influence, and the prognostic value of this biomarker was validated in the training set, the validated data itself, and external data, respectively. This biomarker correlates with tumor immune infiltration and has a high degree of infiltration, poor prognosis, and strong correlation with CD8+T cells. Gene function annotation and other analyses also implied a potential molecular mechanism for ROMO1. In conclusion, we putative ROMO1 as a portal key prognostic gene for the diagnosis and prognosis of PCa, which provides new insights into the diagnosis and treatment of PCa.

Landscape of Carbon Ion Radiotherapy in Prostate Cancer: Clinical Application and Translational Research

Carbon ion radiotherapy (CIRT) is a useful and advanced technique for prostate cancer. This study sought to investigate the clinical efficacy and translational research for prostate cancer with carbon ion radiotherapy. We integrated the data from published articles, clinical trials websites, and our data. The efficacy of CIRT for prostate cancer was assessed in terms of overall survival, biochemical recurrence-free survival, and toxicity response. Up to now, clinical treatment of carbon ion radiotherapy has been carried in only five countries. We found that carbon ion radiotherapy induced little genitourinary and gastrointestinal toxicity when used for prostate cancer treatment. To some extent, it led to improved outcomes in overall survival, biochemical recurrence-free survival than conventional radiotherapy, especially for high-risk prostate cancer. Carbon ion radiotherapy brought clinical benefits for prostate cancer patients, and quality of life assessment indicated that CIRT affected patients to a lesser extent. Potential biomarkers from our omics-based study could be used to predict the efficacy of prostate cancer with CIRT. Carbon ion radiotherapy brought clinical benefits for prostate cancer patients. The omics-based translational research may provide insights into individualized therapy.

CT-guided palladium-103 seed brachytherapy for metastatic adenoid cystic carcinoma: a retrospective study to assess initial safety and effectiveness of percutaneous CT fluoroscopy-guided permanent seed brachytherapy

Purpose

Multiple pulmonary metastases present treatment difficulties in available treatment techniques, which are inconvenient or may damage sufficient pulmonary tissue to cause pulmonary crippling. This retrospective study of a single-community practice evaluated responses to computed tomography (CT)-guided ¹⁰³Pd permanent seed brachytherapy (CTGPSB) in adenoid cystic carcinoma (ACC) synchronous pulmonary metastases. The purpose of the current study was to document that metastatic pulmonary ACC lesions can be controlled with CTGPSB.

Material and methods

Twenty-nine discrete lesions in 14 patients were evaluated with serial CT scans. All were treated with CTGPSB. Lesions were tracked over serial CT scans and volumes measured. Primary endpoint was a reduction in tumor volume on subsequent CT scan. Secondary endpoint was occurrence of CTCAE grades 2-5.

Results

There was a 100% measured reduction in tumor volume (n = 29) at follow-up. Follow-up was a mean of 3.13 years. Baseline tumor volume was a mean of 1.85 ml (range, 0.69-9.15 ml). There were two grade 1 and one grade 2 adverse events, which did not require hospitalization.

Conclusions

CTGPSB for the treatment of multiple ACC pulmonary metastases is effective, with minimal acute complications, as shown in small cohort of subjects of the present study. Further studies evaluating specific dosimetry parameters in this free-hand technique are needed to specify minimal and maximal dose constraints.

Clinical and Preclinical Outcomes of Combining Targeted Therapy With Radiotherapy

In the era of precision medicine, radiation medicine is currently focused on the precise delivery of highly conformal radiation treatments. However, the tremendous developments in targeted therapy are yet to fulfill their full promise and arguably have the potential to dramatically enhance the radiation therapeutic ratio. The increased ability to molecularly profile tumors both at diagnosis and at relapse and the co-incident progress in the field of radiogenomics could potentially pave the way for a more personalized approach to radiation treatment in contrast to the current ‘‘one size fits all’’ paradigm. Few clinical trials to date have shown an improved clinical outcome when combining targeted agents with radiation therapy, however, most have failed to show benefit, which is arguably due to limited preclinical data. Several key molecular pathways could theoretically enhance therapeutic effect of radiation when rationally targeted either by directly enhancing tumor cell kill or indirectly through the abscopal effect of radiation when combined with novel immunotherapies. The timing of combining molecular targeted therapy with radiation is also important to determine and could greatly affect the outcome depending on which pathway is being inhibited.

Multifunctional Hybrid Hydrogel Enhanced Antitumor Therapy through Multiple Destroying DNA Functions by a Triple-Combination Synergistic Therapy

Brachytherapy, as an effective setting for precise cancer therapy in clinic, can lead to serious DNA damage. However, its therapeutic efficacy is always limited by the DNA self-repair property, tumor hypoxia-associated radiation resistance as well as inhomogeneous distribution of the radioactive material. Herein, a multifunctional hybrid hydrogel (¹³¹ I-hydrogel/DOX/GNPs aggregates) is developed by loading gold nanoparticle aggregates (GNPs aggregates) and DOX into a radionuclide iodine-131 (¹³¹ I) labelled polymeric hydrogels (¹³¹ I-PEG-P(Tyr)₈ ) for tumor destruction by completely damaging DNA self-repair functions. This hybrid hydrogel exhibits excellent photothermal/radiolabel stability, biocompatibility, and fluorescence/photothermal /SPECT imaging properties. After local injection, the sustained releasing DOX within tumor greatly inhibits the DNA replication. Meanwhile, GNPs aggregates as a radiosensitizer and photosensitizer show a significant improvement of brachytherapeutic efficacy and cause serious DNA damage. Simultaneously, GNPs aggregates induce mild photothermal therapy under 808 nm laser irradiation, which not only inhibits self-repair of the damaged DNA but also effectively relieves tumor hypoxic condition to enhance the therapeutic effects of brachytherapy, leading to a triple-synergistic destruction of DNA functions. Therefore, this study provides a highly efficient tumor synergistic therapy platform and insight into the synergistic antitumor mechanism in DNA level.

Measurement of sub-zero temperatures in MRI using T1 temperature sensitive soft silicone materials: Applications for MRI-guided cryosurgery

PURPOSE

One standard method, proton resonance frequency shift, for measuring temperature using magnetic resonance imaging (MRI), in MRI-guided surgeries, fails completely below the freezing point of water. Because of this, we have developed a new methodology for monitoring temperature with MRI below freezing. The purpose of this paper is to show that a strong temperature dependence of the nuclear relaxation time T₁ in soft silicone polymers can lead to temperature-dependent changes of MRI intensity acquired with T₁ weighting. We propose the use of silicone filaments inserted in tissue for measuring temperature during MRI-guided cryoablations.

METHODS

The temperature dependence of T₁ in bio-compatible soft silicone polymers was measured using nuclear magnetic resonance spectroscopy and MRI. Phantoms, made of bulk silicone materials and put in an MRI-compatible thermal container with dry ice, allowed temperature measurements ranging from -60°C to + 20°C. T₁ -weighted gradient echo images of the phantoms were acquired at spatially uniform temperatures and with a gradient in temperature to determine the efficacy of using these materials as temperature indicators in MRI. Ex vivo experiments on silicone rods, 4 mm in diameter, inserted in animal tissue were conducted to assess the practical feasibility of the method.

RESULTS

Measurements of nuclear relaxation times of protons in soft silicone polymers show a monotonic, nearly linear, change with temperature (R²  > 0.98) and have a significant correlation with temperature (Pearson's r > 0.99, p < 0.01). Similarly, the intensity of the MR images in these materials, taken with a gradient echo sequence, are also temperature dependent. There is again a monotonic change in MRI intensity that correlates well with the measured temperature (Pearson's r < -0.98 and p < 0.01). The MRI experiments show that a temperature change of 3°C can be resolved in a distance of about 2.5 mm. Based on MRI images and external sensor calibrations for a sample with a gradient in temperature, temperature maps with 3°C isotherms are created for a bulk phantom. Experiments demonstrate that these changes in MRI intensity with temperature can also be seen in 4 mm silicone rods embedded in ex vivo animal tissue.

CONCLUSIONS

We have developed a new method for measuring temperature in MRI that potentially could be used during MRI-guided cryoablation operations, reducing both procedure time and cost, and making these surgeries safer.

3D-printed template and optical needle navigation in CT-guided iodine-125 permanent seed implantation

Purpose

To preliminarily verify the accuracy of navigation-assisted seed implantation by comparing pre-operative and actual differences in puncture characteristics and dosimetry in computed tomography (CT)-guided, navigation-assisted radioactive iodine-125 seed implantation, using 3D-printed templates for malignant tumors’ treatment.

Material and methods

A total of 27 tumor patients, who were treated with seed implantation under combination guidance in our hospital between December 2019 and December 2020 were enrolled in this study. Navigation needles (n = 1-3) were placed in each patient to obtain pre-operative and intra-operative puncture information, such as angle, depth, insertion point, and tip position. Moreover, dosimetry parameters in pre-operative and post-operative plans, including D₉₀, V₁₀₀, V₁₅₀, V₂₀₀, minimum peripheral dose (MPD), conformal index, external index, and homogeneity index of target area were investigated.

Results

Mean errors of the angle, depth, insertion point, and tip position were 0.5 ±0.5°, 4.0 ±2.0 mm, 1.7 ±1 mm, and 3.1 ±1.8 mm, respectively. There were no significant differences between intra-operative and pre-operative angles (p = 0.271), but there was a significant difference in the depth (p = 0.002). Errors of the angle, depth, and insertion point were larger for the pelvic/retroperitoneal area than for the head and neck/chest wall (p < 0.05). With the exception of MPD, there was no significant difference in dosimetry indices between post-operative and preoperative plans (p > 0.05).

Conclusions

Seed implantation under combination guidance showed good accuracy, and the actual intra-operative puncture information and post-operative doses were in agreement with those in the pre-operative plan, thereby demonstrating promising prospects for further development.

Treatment Strategies for High-Risk Localized and Locally Advanced and Oligometastatic Prostate Cancer

Simple Summary

The definitions of locally advanced and oligometastatic prostate cancer are ambiguous, and there are no standard treatments for these. Although multidisciplinary treatment combining systemic and local treatment may be effective, there are many unresolved issues such as the choice of local treatment, use of new endocrine agents and chemotherapy, and selection of optimal patients. The present article discusses the definitions, diagnoses, and treatment of very high-risk prostate cancer and oligometastatic prostate cancer.

Abstract

Despite the significant advances in the treatment of high-risk prostate cancer, patients with very high-risk features such as being locally advanced (clinical stage T3–4 or minimal nodal involvement), having a high Gleason pattern, or with oligometastasis may still have a poor prognosis despite aggressive treatment. Multidisciplinary treatment with both local and systemic therapies is thought to be effective, however, unfortunately, there is still no standard treatment. However, in recent years, local definitive therapy using a combination of radiotherapy and androgen deprivation is being supported by several randomized clinical trials. This study reviews the current literature with a focus on the definition of very high-risk prostate cancer, the role of modern imaging, and its treatment options.

Stereotactic Ablative Brachytherapy: Recent Advances in Optimization of Radiobiological Cancer Therapy

Brachytherapy (BT), a type of focal anti-cancer radiotherapy, delivers a highly focused radiation dose to localized tumors, sparing surrounding normal tissues. Recent technological advances have helped to increase the accuracy of BT and, thus, improve BT-based cancer treatment. Stereotactic ablative brachytherapy (SABT) was designed to improve the ablative effect of radiation, which was achieved via improved image guidance, and calculation of ablative dose, shorter treatment duration, and better organ preservation. Recently collected data characterized SABT as having the potential to cure various early-stage cancers. The method provides higher tumor control rate levels that were previously achievable only by surgical resection. Notably, SABT is suitable for application with unresectable malignancies. However, the pathological assessment of SABT irradiated tumors is limited due to difficulties in specimen acquisition. Prostate, lung, liver, and gynecological cancers are the most commonly reported SABT-treated malignancies. This study will give an overview of SABT, focusing on the advances in SABT optimization, and provide insights on the future benefits of the combined application of SABT with cancer immunotherapies.

Does the sequence of high-dose rate brachytherapy boost and IMRT for prostate cancer impact early toxicity outcomes? Results from a single institution analysis

•

The optimal sequence of HDR-BT boost and EBRT for prostate cancer is unclear.

•

We compared early toxicity based on the timing of HDR-BT boost.

•

The timing of HDR-BT was not based on any specific patient or clinical factors.

•

We found no difference in early GI/GU toxicity between the two groups.

•

Longer follow-up is needed to evaluate late toxicity and long-term disease control.

Background

We present the first report comparing early toxicity outcomes with high-dose rate brachytherapy (HDR-BT) boost upfront versus intensity modulated RT (IMRT) upfront combined with androgen deprivation therapy (ADT) as definitive management for intermediate risk or higher prostate cancer.

Methods and Materials

We reviewed all non-metastatic prostate cancer patients who received HDR-BT boost from 2014 to 2019. HDR-BT boost was offered to patients with intermediate-risk disease or higher. ADT use and IMRT target volume was based on NCCN risk group. IMRT dose was typically 45 Gy in 25 fractions to the prostate and seminal vesicles ± pelvic lymph nodes. HDR-BT dose was 15 Gy in 1 fraction, delivered approximately 3 weeks before or after IMRT. The sequence was based on physician preference. Biochemical recurrence was defined per ASTRO definition. Gastrointestinal (GI) and Genitourinary (GU) toxicity was graded per CTCAE v5.0. Pearson Chi-squared test and Wilcoxon tests were used to compare toxicity rates. P-value < 0.05 was significant.

Results

Fifty-eight received HDR-BT upfront (majority 2014–2016) and 57 IMRT upfront (majority 2017–2018). Median follow-up was 26.0 months. The two cohorts were well-balanced for baseline patient/disease characteristics and treatment factors. There were differences in treatment sequence based on the year in which patients received treatment. Overall, rates of grade 3 or higher GI or GU toxicity were <1%. There was no significant difference in acute or late GI or GU toxicity between the two groups.

Conclusion

We found no significant difference in GI/GU toxicity in intermediate-risk or higher prostate cancer patients receiving HDR-BT boost upfront versus IMRT upfront combined with ADT. These findings suggest that either approach may be reasonable. Longer follow-up is needed to evaluate late toxicity and long-term disease control.

Computed tomography guided interstitial percutaneous high-dose-rate brachytherapy in the management of lung malignancies. A review of the literature

A growing number of patients with lung cancer are not amenable to surgery due to their age or comorbidities. For this reason, local ablative techniques have gained increasing interest recently in the management of inoperable lung tumors. High-dose-rate percutaneous interstitial brachytherapy, performed under CT-guidance, is a newer form of brachytherapy and is a highly conformal radiotherapy technique. The aim of this study was to describe this method and review the existing literature. Eight articles comprising 234 patients reported toxicity and clinical outcome. The follow-up ranged from 6 to 28 months. Diverse fractionation schemes were reported, with 20 Gy in a single fraction being the most frequently utilized. Toxicity was limited; major pneumothoraces occurred after only 8% of the interventions. Local control rates at one year ranged between 37% and 91%. In conclusion, high-dose-rate percutaneous interstitial brachytherapy is a safe, fast, and efficient treatment option for inoperable lung tumors.