Prostate Radiotherapy Research Articles

1655: Radiation-induced T-lymphocyte Apoptosis and Prostate Radiotherapy: final data of the French trial

1655: Radiation-induced T-lymphocyte Apoptosis and Prostate Radiotherapy: final data of the French trial

2664: OARs auto-segmentation in cervical and prostate radiotherapy: evaluation of four automatic tools

2664: OARs auto-segmentation in cervical and prostate radiotherapy: evaluation of four automatic tools

2549: Prostate radiotherapy with rectal spacer in patients with bowel comorbidities - one year on.

2549: Prostate radiotherapy with rectal spacer in patients with bowel comorbidities - one year on.

2250: Accuracy of seed- and grey value match in Elekta XVI software for prostate and mamma radiotherapy

2250: Accuracy of seed- and grey value match in Elekta XVI software for prostate and mamma radiotherapy

2513: Testing the feasibility of image matching prostate radiation therapy with online 2D MRI CINE imaging

2513: Testing the feasibility of image matching prostate radiation therapy with online 2D MRI CINE imaging

636: Dosimetric factors impacting urethral toxicity following stereotactic prostate radiotherapy

636: Dosimetric factors impacting urethral toxicity following stereotactic prostate radiotherapy

1674: Bladder and rectal dose accumulation for prostate radiotherapy agrees with planned dose goals

1674: Bladder and rectal dose accumulation for prostate radiotherapy agrees with planned dose goals

1401: End-to-end automatic treatment planning for prostate radiotherapy

1401: End-to-end automatic treatment planning for prostate radiotherapy

2221: Quantifying dose errors in prostate radiotherapy due to 6DoF prostate and pelvic lymph node motion

2221: Quantifying dose errors in prostate radiotherapy due to 6DoF prostate and pelvic lymph node motion

376: The impact of margin reduction on dose distribution of prostate radiotherapy with 1.5-T MR-Linac

376: The impact of margin reduction on dose distribution of prostate radiotherapy with 1.5-T MR-Linac

786: Utilizing Pareto optimization to refine ML training data in prostate radiotherapy planning

786: Utilizing Pareto optimization to refine ML training data in prostate radiotherapy planning

1411: Quantitative and qualitative evaluation of an automated planning solution for prostate radiotherapy

1411: Quantitative and qualitative evaluation of an automated planning solution for prostate radiotherapy

Evaluation of safety margins for cone beam CT-based adaptive prostate radiotherapy

Adaptive radiotherapy is characterized by the use of a daily imaging system, such as CBCT (Cone-Beam Computed Tomography) images to re-optimize the treatment based on the daily anatomy and position of the patient. By systematically re-delineating the Clinical Target Volume (CTV) at each fraction, target delineation uncertainty features a random component instead of a pure systematic. The goal of this work is to identify the random and systematic contributions of the delineation error and compute a new relevant Planning Target Volume (PTV) safety margin.169 radiotherapy sessions from 10 prostate cancer patients treated on the Varian ETHOS treatment system have been analyzed. Intra-patient and inter-patient delineation variabilities were computed in six directions, by considering the prostate as a rigid, non-rotating volume. By doing so, we were able to directly compare the delineations done by the physicians on daily CBCT images with the initial delineation done on the CT-sim and MRI, and sort them by direction using the polar coordinates of the points. The computed variabilities were then used to compute a PTV margin based on Van Herk margin recipe.The total margin computed with random and systematic delineation uncertainties was of 2.7, 2.4, 5.6, 4.8, 4.9 and 3.6 mm in the left, right, anterior, posterior, cranial and caudal directions, respectively.According to our results, the gain offered by the separation of the delineation uncertainty into systematic and random contributions due to the adaptive delineation process justifies a reduction of the PTV margin down to 3 to 5 mm in every direction.

Comparison of commercial atlas-based automatic segmentation software for prostate radiotherapy treatment planning.

This study aims to assess the accuracy of automatic atlas-based contours for various key anatomical structures in prostate radiotherapy treatment planning. The evaluated structures include the bladder, rectum, prostate, seminal vesicles, femoral heads and penile bulb. CT images from 20 patients who underwent intensity-modulated radiotherapy were randomly chosen to create an atlas library. Atlas contours of the seven anatomical structures were generated using four software packages: ABAS, Eclipse, MIM, and RayStation. These contours were then compared to manual delineations performed by oncologists, which served as the ground truth. Evaluation metrics such as dice similarity coefficient (DSC), mean distance to agreement (MDA), and volume ratio (VR) were calculated to assess the accuracy of the contours. Additionally, the time taken by each software to generate the atlas contour was recorded. The mean DSC values for the bladder exhibited strong agreement (>0.8) with manual delineations for all software except for Eclipse and RayStation. Similarly, the femoral heads showed significant similarity between the atlas contours and ground truth across all software, with mean DSC values exceeding 0.9 and MDA values close to zero. On the other hand, the penile bulb displayed only moderate agreement with the ground truth, with mean DSC values ranging from 0.5 to 0.7 for all software. A similar trend was observed in the prostate atlas contours, except for MIM, which achieved a mean DSC of over 0.8. For the rectum, both ABAS and MIM atlases demonstrated strong agreement with the ground truth, resulting in mean DSC values of more than 0.8. Overall, MIM and ABAS outperformed Eclipse and RayStation in both DSC and MDA. These results indicate that the atlas-based segmentation employed in this study produces acceptable contours for the anatomical structures of interest in prostate radiotherapy treatment planning.

Surgical management of rectal cancer with synchronous treatment of prostate cancer.

To assess the safety and efficacy of synchronous treatments for rectal (RC) and prostate (PC) cancers. Single-center retrospective study (2007-2021) of patients treated with neoadjuvant radiotherapy (RT) and total mesorectal excision (TME) for RC with synchronous PC treatment. The endpoints were 30-day postoperative severe complications, R0 resection rates, 3-year disease-free survival (DFS) and 3-year overall survival (OS). Among the 16 patients, 15 (93.7%) received neoadjuvant pelvic RT (40-50.4 Gray) followed by either transperineal high dose rate prostate brachytherapy (62.5%), prostate external RT boost (25.0%), or androgen deprivation therapy (ADT) alone (6.3%). One (6.3%) patient received neoadjuvant rectal brachytherapy and ADT. Pelvic RT was combined with chemotherapy in 87.5% of cases. TME was performed in all patients with low anterior resection (87.5%) or abdominoperineal resection (12.5%), primarily using minimally invasive surgery (87.5%). The R0 resection rate was 93.8%. Six (37.5%) patients experienced 30-day Clavien-Dindo grade IIIb complications, including one (7.1%) anastomotic leak. After a median follow-up of 39.0months, 63.6% of diverting ileostomies were reversed. Three-year DFS from RC was 71.4% (CI 40.2-88.3) and 3-year OS was 84.4% (CI 95% 50.4-95.9). No PC recurrence or death occurred. Synchronous management of RC and PC with pelvic RT followed by curative prostate RT doses and TME showed acceptable morbidity and oncologic results. Prostate brachytherapy, the most commonly used treatment modality, allowed avoidance of prostatectomy and additional external RT to the rectum. PC should not limit the curative intent of RC, as all recurrences were from rectal origin.

Clinical evaluation of the efficacy of limbus artificial intelligence software to augment contouring for prostate and nodes radiotherapy.

To determine if Limbus, an artificial intelligence (AI) auto-contouring software, can offer meaningful time savings for prostate radiotherapy treatment planning. Three clinical oncologists recorded the time taken to contour prostate and seminal vesicles, lymph nodes, bladder, rectum, bowel, and femoral heads on CT scans for 30 prostate patients (15 prostate, 15 prostate and nodes). Limbus 1.6.0 was used to generate these contours on the 30 CT scans. The time taken by the oncologists to modify individual Limbus contours was noted and compared with manual contouring times. The geometric similarity of Limbus and expert contours was assessed using the Dice Similarity Coefficient (DSC), and the dosimetric impact of using un-edited Limbus organs at risk contours was studied. Limbus reduced the time to produce clinically acceptable contours by 26 minutes for prostate and nodes patients and by 13 minutes for the prostate only patients. DSC values of greater than 0.7 were calculated for all contours, demonstrating good initial agreement. A dosimetric study showed that 5 of the 20 plans optimized using unmodified AI structures required unnecessary compromise of PTV coverage, highlighting the importance of expert review. Limbus offers significant time saving and has become an essential part of our clinical practice. This article is the first to include bowel and lymph nodes when assessing potential time savings using Limbus software. It demonstrates that Limbus can be used as an aid for prostate and node radiotherapy treatment planning.

Current Systemic Therapy in Men with Metastatic Castration-Sensitive Prostate Cancer.

This review aims to explore the evolving landscape of treatments available for metastatic castration-sensitive prostate cancer (mCSPC) patients. In less than a decade, evidence was chronologically provided that (1) systemic treatment intensification with docetaxel improves outcomes, including survival, in men with mCSPC, (2) then that these outcomes are also improved when a second-generation androgen receptor pathway inhibitor (ARPI) is combined with androgen deprivation therapy (ADT), and (3) using a "triplet systemic therapy," which consists in the combination of ADT, an ARPI and docetaxel, further improves outcomes, including survival. Radiotherapy to the prostate combined with ADT alone is now recommended in men with low-volume mCSPC. Combining prostate radiotherapy and intensified systemic treatment including abiraterone may be synergistic as suggested in the PEACE-1 trial. Also, the role of metastases-directed local therapies (mostly stereotactic radiotherapy) is currently being assessed in phase 3 trials. Finally, the integration of biomarkers (e.g. BRCA2 gene alterations, PTEN loss, PSMA expression) for decision making is not currently established, though trials are also currently underway. Importantly, most evidence currently available was obtained in men with de novo metastases, while for those with metastatic relapse after definitive local treatment, the role of treatment intensification is less well established. Treatment intensification is nowadays the standard of care for patients with de novo mCSPC as it leads to outcomes improvement, including survival, and the standard of care is evolving almost on a yearly basis.

Developing and validating a simple urethra surrogate model to facilitate dosimetric analysis to predict genitourinary toxicity

PurposeThe urethra is a critical structure in prostate radiotherapy planning; however, it is impossible to visualise on CT. We developed a surrogate urethra model (SUM) for CT-only planning workflow and tested its geometric and dosimetric performance against the MRI-delineated urethra (MDU). MethodsThe SUM was compared against 34 different MDUs (within the treatment PTV) in patients treated with 36.25Gy (PTV)/40Gy (CTV) in 5 fractions as part of the PACE-B trial. To assess the surrogate's geometric performance, the Dice similarity coefficient (DSC), Hausdorff distance (HD), mean distance to agreement (MDTA) and the percentage of MDU outside the surrogate (UOS) were calculated. To evaluate the dosimetric performance, a paired t-test was used to calculate the mean of differences between the MDU and SUM for the D99, D98, D50, D2 and D1. The D(n) is the dose (Gy) to n% of the urethra. ResultsThe median results showed low agreement on DSC (0.32; IQR 0.21–0.41), but low distance to agreement, as would be expected for a small structure (HD 8.4mm (IQR 7.1–10.1mm), MDTA 2.4mm (IQR, 2.2mm-3.2mm)). The UOS was 30% (IQR, 18–54%), indicating nearly a third of the urethra lay outside of the surrogate. However, when comparing urethral dose between the MDU and SUM, the mean of differences for D99, D98 and D95 were 0.12Gy (p=0.57), 0.09Gy (p=0.61), and 0.11Gy (p=0.46) respectively. The mean of differences between the D50, D2 and D1 were 0.08Gy (p=0.04), 0.09Gy (p=0.02) and 0.1Gy (p=0.01) respectively, indicating good dosimetric agreement between MDU and SUM. ConclusionWhile there were geometric differences between the MDU and SUM, there was no clinically significant difference between urethral dose-volume parameters. This surrogate model could be validated in a larger cohort and then used to estimate the urethral dose on CT planning scans in those without an MRI planning scan or urinary catheter.

Radical prostatectomy versus radiotherapy as local therapy for primary tumors in patients with oligometastatic prostate cancer.

We compared radical prostatectomy (RP) and radiotherapy (RT) as local therapies for primary tumors and examined their associations with survival outcomes and urinary tract complications in patients with oligometastatic prostate cancer (omPC). We evaluated the data of 85 patients diagnosed with omPC who underwent local therapy for primary tumors between January 2008 and December 2018. Of the 85 patients, 31 underwent prostate RT, while 54 underwent RP. Oligometastatic disease was defined as the presence of fewer than five metastatic lesions without visceral metastasis. Urinary tract complications, progression-free survival (PFS), cancer-specific survival (CSS), and overall survival (OS) were evaluated using the Kaplan-Meier method and Cox regression analyses. Patients treated with RT showed higher prostate-specific antigen levels. There was no significant difference in the 5-year PFS (52.5% vs. 37.9%, p=0.351), CSS (67.6% vs. 84.7%, p=0.473), or OS (63.6% vs. 73.8%, p=0.897) between the RT and RP groups. In the multivariate analyses, the type of local therapy was not associated with PFS (hazard ratio [HR]=1.334, p=0.356), CSS (HR=0.744, p=0.475), or OS (HR=0.953, p=0.897). Therefore, RP seems to be a possible treatment option for patients with omPC, exhibiting oncologic outcomes comparable to those with RT.

Effect of Bacille Calmette-Guérin for Non-Muscle-Invasive Bladder Cancer After Prostate Radiotherapy.

Little is known about the impact of prior prostate radiation therapy (RT) on the Bacille Calmette-Guerin (BCG) immunotherapy response in patients with non-muscle invasive bladder cancer (NMIBC). We hypothesized that the damaging radiation effects on the bladder could negatively influence BCG efficacy. Men with a history of high-risk NMIBC were identified within the Surveillance, Epidemiology, and End Results-Medicare database. All patients completed adequate BCG defined as at least 5 plus 2 treatments completed within 12 months. Patients were stratified into 2 groups: with prior RT for prostate cancer and without prior RT before the diagnosis of NMIBC. The primary endpoint was a 5-year composite for progression defined as disease progression requiring systemic chemotherapy, checkpoint inhibitors, radical or partial cystectomy, or cancer-specific death. We identified 3,466 patients with NMIBC, including 145 with prior RT for prostate cancer. Five-year progression occurred in 471 patients (13.6%). Patients with prior RT were older than patients without prior RT (77.0 vs 75.0 years; P < .001). The distribution of T stage was significantly different at diagnosis between the RT and non-RT groups (RT: Ta, 44.8%; Tis, 18.6%; T1, 36.6%; without RT: Ta, 40.9%; Tis, 10.8%; T1, 48.3%; P = .002). No difference in the risk of total progression was observed between patients with and without prior RT (P = .67). Similarly, no difference was observed after multivariable adjustment (hazard ratio, 0.99; 95% CI, 0.61-1.58; P = .95). For patients with NMIBC who undergo adequate BCG treatment, prior RT for prostate cancer was not associated with worse 5-year progression-free survival.