Radiotherapy For Prostate Cancer Research Articles

A patient-specific auto-planning method for MRI-guided adaptive radiotherapy in prostate cancer

Background and purposeFast and automated generation of treatment plans is desirable for magnetic resonance imaging (MRI)-guided adaptive radiotherapy (MRIgART). This study proposed a novel patient-specific auto-planning method and validated its feasibility in improving the existing online planning workflow. Materials and methodsData from 40 patients with prostate cancer were collected retrospectively. A patient-specific auto-planning method was proposed to generate adaptive treatment plans. First, a population dose-prediction model (M0) was trained using data from previous patients. Second, a patient-specific model (Mps) was created for each new patient by fine-tuning M0 with the patient’s data. Finally, an auto plan was optimized using the parameters derived from the predicted dose distribution by Mps. The auto plans were compared with manual plans in terms of plan quality, efficiency, dosimetric verification, and clinical evaluation. ResultsThe auto plans improved target coverage, reduced irradiation to the rectum, and provided comparable protection to other organs-at-risk. Target coverage for the planning target volume (+0.61 %, P = 0.023) and clinical target volume 4000 (+1.60 %, P < 0.001) increased. V2900cGy (−1.06 %, P = 0.004) and V1810cGy (−2.49 %, P < 0.001) to the rectal wall and V1810cGy (−2.82 %, P = 0.012) to the rectum were significantly reduced. The auto plans required less planning time (−3.92 min, P = 0.001), monitor units (−46.48, P = 0.003), and delivery time (−0.26 min, P = 0.004), and their gamma pass rates (3 %/2 mm) were higher (+0.47 %, P = 0.014). ConclusionThe proposed patient-specific auto-planning method demonstrated a robust level of automation and was able to generate high-quality treatment plans in less time for MRIgART in prostate cancer.

Multi-scale anatomical regularization for domain-adaptive segmentation of pelvic CBCT images.

Cone beam computed tomography (CBCT) image segmentation is crucial in prostate cancer radiotherapy, enabling precise delineation of the prostate gland for accurate treatment planning and delivery. However, the poor quality of CBCT images poses challenges in clinical practice, making annotation difficult due to factors such as image noise, low contrast, and organdeformation. The objective of this study is to create a segmentation model for the label-free target domain (CBCT), leveraging valuable insights derived from the label-rich source domain (CT). This goal is achieved by addressing the domain gap across diverse domains through the implementation of a cross-modality medical image segmentationframework. Our approach introduces a multi-scale domain adaptive segmentation method, performing domain adaptation simultaneously at both the image and feature levels. The primary innovation lies in a novel multi-scale anatomical regularization approach, which (i) aligns the target domain feature space with the source domain feature space at multiple spatial scales simultaneously, and (ii) exchanges information across different scales to fuse knowledge from multi-scaleperspectives. Quantitative and qualitative experiments were conducted on pelvic CBCT segmentation tasks. The training dataset comprises 40 unpaired CBCT-CT images with only CT images annotated. The validation and testing datasets consist of 5 and 10 CT images, respectively, all with annotations. The experimental results demonstrate the superior performance of our method compared to other state-of-the-art cross-modality medical image segmentation methods. The Dice similarity coefficients (DSC) for CBCT image segmentation results is %, and the average symmetric surface distance (ASSD) is . Statistical analysis confirms the statistical significance of the improvements achieved by ourmethod. Our method exhibits superiority in pelvic CBCT image segmentation compared to its counterparts.

Enhancing Visualization of Gold Markers in Prostate Cancer Radiation Therapy Planning Through MRI Pulse Sequence Optimization

Prostate cancer treatment often involves the use of gold markers to enhance the accuracy of radiation therapy. However, the visualization of these markers using MRI remains a challenge due to their small size and susceptibility to artifacts. This study investigates the optimization of MRI pulse sequences to improve the visibility of gold markers in the context of radiation therapy simulation for prostate cancer patients. By comparing various pulse sequences and their parameters, we aim to identify the optimal configuration that provides the best contrast and minimal artifacts.

116 Factors Associated with Successful CT Simulation in Prostate Cancer Radiotherapy

116 Factors Associated with Successful CT Simulation in Prostate Cancer Radiotherapy

Stereotactic Radiation Therapy for Localized Prostate Cancer: 10-Year Outcomes From Three Prospective Trials

Background and purposeStereotactic ablative radiotherapy (SABR) is growingly accepted for the treatment of localized prostate cancer with recent randomized trials showing non-inferiority compared to conventional or moderately hypofractionated radiotherapy. The natural history of prostate cancer necessitates extended surveillance for recurrence; however, there are few prospective studies reporting long-term outcomes. Materials and methodsThis study included patients with low and intermediate risk localized prostate cancer from three Canadian clinical trials enrolled from 2006-2013. All patients received SABR to the prostate consisting of 35-40 Gy in 5 fractions over 11-29 days. PSA, distant metastasis, and vital status were prospectively recorded. Occurrence of second malignancy after treatment was assessed by chart review and classified using modified Cahan's criteria. Results267 patients were included. Median follow up was 10.3 years (IQR 7.8 – 12.7). 10-year BF (95% CI) was 7.7% (3.9-11.5). 10-year OS, PCSS, and FFM were 84.1% (79.3 – 89.1%), 99.2% (98.1 – 100), and 98.8% (97.5-100), respectively. 27/267 (10.1%) patients experienced a SM, with 6/27 patients (22.2%) classified as having a SM likely (n=3) or possibly (n=3) related to prior radiotherapy. 10-year freedom from SM was 89.2%. ConclusionSABR shows excellent long-term disease control for low and intermediate risk localized prostate cancer. Patients treated for prostate cancer have a moderate risk of second malignancy, consistent with background rates for the population.

Hypofractionated Dose Escalation Radiotherapy for High-Risk Prostate Cancer: the survival analysis of the Prostate Cancer Study-5 (PCS-5), a GROUQ-led phase III trial

Background and objectiveProstate Cancer Study 5 (PCS5) compared conventional fractionated radiotherapy (CFRT) with hypofractionated radiotherapy (HFRT) in high-risk prostate cancer (PCa) patients, hypothesizing similar toxicity and survival outcomes. This report presents the efficacy analysis. MethodsPCS5 is a Canadian multicenter, open-label, phase 3 randomized control trial. Men with histologically proven, clinically localized PCa with one or more high-risk features (T3/T4, Gleason score ≥8, and prostate-specific antigen >20) were eligible. Patients were randomized 1:1 to CFRT (76 Gy/38 fractions [Fx] to the prostate and 46 Gy/23 Fx to the pelvic lymph nodes [PLNs]) or HFRT (68 Gy/25 Fx to the prostate and 45 Gy/25 Fx to the PLNs) and 28 mo of androgen suppression. The primary endpoint was toxicity; secondary endpoints included survival outcomes. Key findings and limitationsOf 329 patients, 164 were randomized to HFRT and 165 to CFRT, with 159 in the HFRT arm and 160 in the CFRT arm included in survival analyses. At the 5-yr median follow-up, there were no significant differences in overall survival (OS; 90.3% vs 89.7%; risk ratio [RR]: 1.01; 95% confidence interval [CI]: 0.93–1.09), PCa-specific survival (PCSS; 97.4% vs 97.5%; RR: 1.00; 95% CI: 0.93–1.07), biochemical recurrence–free survival (BCRFS; 85.2% vs 85.2%; RR: 1.00; 95% CI: 0.91–1.10), or distant metastasis–free survival (DMFS; 87.1% vs 87.1%; RR: 1.00; 95% CI: 0.92–1.09). Hazard ratios were 0.92 (95% CI: 0.56–1.53) for OS, 1.31 (95% CI: 0.46–3.78) for PCSS, 0.85 (95% CI: 0.56–1.30) for BCRFS, and 0.90 (95% CI: 0.56–1.43) for DMFS. Sample size was a limiting factor. Conclusions and clinical implicationsThere were no differences in survival outcomes between HFRT (68 Gy/25 Fx) and CFRT (76 Gy/38 Fx). HFRT, including PLN radiotherapy and long-term androgen deprivation therapy, should be considered a new standard of care for high-risk PCa patients undergoing external beam radiotherapy.

44 Ultrahypofractionated Versus Moderately Hypofractionated and Conventionally Fractionated Pelvic Radiotherapy for Prostate Cancer: Outcomes from 3 Prospective Clinical Trials

44 Ultrahypofractionated Versus Moderately Hypofractionated and Conventionally Fractionated Pelvic Radiotherapy for Prostate Cancer: Outcomes from 3 Prospective Clinical Trials

910: Comparison of Eclipse and RayStation in Multi-Criteria Optimization in Prostate Cancer Radiotherapy

910: Comparison of Eclipse and RayStation in Multi-Criteria Optimization in Prostate Cancer Radiotherapy

2943: Ultra hypofractionated radiotherapy in high risk prostate cancer: a real world experience

2943: Ultra hypofractionated radiotherapy in high risk prostate cancer: a real world experience

2592: Early Results of Curative Intent Radiotherapy in Low Burden Metastatic Prostate Cancer

2592: Early Results of Curative Intent Radiotherapy in Low Burden Metastatic Prostate Cancer

1280: Stereotactic Radiotherapy and ARTA in metastatic Castration-Resistant Prostate Cancer

1280: Stereotactic Radiotherapy and ARTA in metastatic Castration-Resistant Prostate Cancer

2802: Ultra-hypofractionated radiotherapy in High risk localised prostate cancer

2802: Ultra-hypofractionated radiotherapy in High risk localised prostate cancer

1891: The impact of fiducial markers-based image guided radiotherapy for prostate cancer.

1891: The impact of fiducial markers-based image guided radiotherapy for prostate cancer.

2710: Surface guided radiotherapy for prostate cancer: a single institution review of set up errors

2710: Surface guided radiotherapy for prostate cancer: a single institution review of set up errors

2536: Long term outcomes of stereotactic MR-guided adaptive radiotherapy for prostate cancer

2536: Long term outcomes of stereotactic MR-guided adaptive radiotherapy for prostate cancer

2991: Rectal bleeding after curative intended radiotherapy for prostate cancer

2991: Rectal bleeding after curative intended radiotherapy for prostate cancer

1212: Assessing a unique bladder preparation protocol for patients undergoing prostate cancer radiotherapy

1212: Assessing a unique bladder preparation protocol for patients undergoing prostate cancer radiotherapy

The risk of second malignancies following prostate cancer radiotherapy in the era of conformal radiotherapy: astatement of the Prostate Cancer Working Group of the German Society of Radiation Oncology (DEGRO).

Asignificant number of prostate cancer patients are long-term survivors after primary definitive therapy, and the occurrence of late side effects, such as second primary cancers, has gained interest. The aim of this editorial is to discuss the most current evidence on second primary cancers based on six retrospective studies published in 2021-2024 using large data repositories not accounting for all possible confounding factors, such as smoking or pre-existing comorbidities. Overall, prostate cancer patients treated with curative radiotherapy have an increased risk (0.7-1%) of the development of second primary cancers compared to patients treated with surgery up to 25years after treatment. However, current evidence suggests that the implementation of intensity modulated radiation therapy is not increasing the risk of second primary cancers compared to conformal 3D-planned radiotherapy. Furthermore, increasing evidence indicates that highly conformal radiotherapy techniques may not increase the probability of second primary cancers compared to radical prostatectomy. Consequently, future studies should consider the radiotherapy technique and other confounding factors to provide amore accurate estimation of the occurrence of second primary cancers.

Androgen deprivation therapy and postprostatectomy radiation: What is the optimal duration?

There is uncertainty regarding the optimal duration of androgen deprivation therapy with postoperative radiation in prostate cancer. We seek to provide clarity through our interpretation of the RADICALS‐HD trial.

Clinical and Dosimetric Comparison Between Non-image Guided Radiation Therapy and Fiducial-Based Image Guided Radiation Therapy With or Without Reduced Margin in Intensity Modulated Radiation Therapy for Prostate Cancer

PurposeThis study aimed to compare the outcomes and toxicities between patients treated with image-guided radiation therapy (IGRT) using fiducial markers and non-IGRT in intensity-modulated radiation therapy (IMRT) for prostate cancer. Methods and MaterialsIn total, 518 patients with intermediate- and high-risk prostate cancer received IMRT with 78 Gy in 39 fractions after neoadjuvant androgen deprivation therapy for at least 3 months. Of these patients, 371 were in the non-IGRT group and 147 in the IGRT group, including the IGRT-A group using the same margins as the non-IGRT group and the IGRT-B group using reduced margins. The median follow-up periods for the non-IGRT, IGRT-A, and IGRT-B groups were 99 months, 88 months, and 63 months, respectively. Results: The 5-year biochemical recurrence-free survival rates in the non-IGRT, IGRT-A, and IGRT-B groups were 88%, 95%, and 98% (non-IGRT vs. IGRT-A: p = 0.396, IGRT-A vs. IGRT-B: p = 0.426), respectively. Those for intermediate- and high-risk patients were 94%, 93%, and 96% (non-IGRT vs. IGRT-A: p = 0.916, IGRT-A vs. IGRT-B: p = 0.646) and 87%, 96%, and 100% (non-IGRT vs. IGRT-A: p = 0.500, IGRT-A vs. IGRT-B: p = 0.483), respectively. For the non-IGRT and IGRT-A groups, the rates of acute grade ≥ 2 gastrointestinal (GI) toxicities and late grade ≥ 2 genitourinary (GU) toxicities were 17% and 7% (p = 0.019); and 28% and 16% (p = 0.028), respectively. In the IGRT-A and IGRT-B groups, the rates of acute grade ≥ 2 GU toxicities were 45% and 21% (p = 0.003). All V60Gy and V70Gy values of the bladder and rectal walls in the IGRT-B group were smaller than those in the IGRT-A group. Conclusions: IGRT with fiducial markers results in lower acute and late toxicities compared with non-IGRT in IMRT for intermediate- and high-risk prostate cancer. Moreover, the toxicities are further decreased by reducing the margins in the treatment planning under IGRT. These processes do not decrease the biochemical recurrence-free survival rates.