Salvage Radiotherapy Research Articles

Urothelial carcinoma of the upper urinary tract

Urothelial carcinoma of the upper urinary tract (upper tract urothelial carcinoma, UTUC) is less common than bladder carcinoma with nearly identical risk factors and has a poorer prognosis. The standard diagnostic procedure is imaging of the upper urinary tract by computed tomography urography. In cases of diagnostic uncertainty, a diagnostic ureterorenoscopy with biopsy sampling can be performed in addition to urine cytology. Treatment depends primarily on the stage and grading of the tumor. Depending on the extent and localization, organ-preserving treatment or radical nephroureterectomy is indicated. Perioperative systemic treatment in high-risk UTUC can be performed in both neoadjuvant and adjuvant settings, although the current data on neoadjuvant chemo- and immunotherapy do not yet allow standard application. For metastatic disease, amultimodal treatment approach consisting of cisplatin-based or carboplatin-based chemotherapy, immunotherapy, and treatment with enfortumab vedotin can be considered. Salvage surgery, radiotherapy and metastasectomy are available for rare individual cases.

Neurocognitive function outcomes in NRG/RTOG 0534, the SPPORT trial.

12022 Background: RTOG 0534 established the benefit of adding of short term androgen deprivation therapy (PBRT+STADT, Arm 2) to prostate bed salvage radiotherapy (PBRT, Arm 1), and demonstrated that elective pelvic lymph node irradiation combined with STADT (PBRT+STADT+PLNRT, Arm 3) results in further reductions in progression. Longitudinal monitoring of neurocognitive function (NCF) was conducted to evaluate the hypothesis that patients treated with STADT will demonstrate greater decline in NCF compared to patients receiving PBRT alone. Methods: Patients were administered the Clinical Trial Battery [Hopkins Verbal Learning Test – Revised (HVLT-R), Trail Making Test (TMT), and the Controlled Oral Word Association (COWA) test] by certified test administrators at baseline, and at 6 weeks (6w), 1 year (1yr), and 5 years after the end of RT (5yr). Raw NCF tests scores were converted to standardized z-scores adjusted for age and education when necessary. Analyses included z-score change and reliable change index (RCI) determined decline compared to baseline, and longitudinal mixed effect regression models using z-scores. To control for multiplicity, p < 0.025 is required for statistical significance. Results: Among the 1716 analyzable patients, 429 consented to NCF monitoring. There were no significant differences in sociodemographic or clinical characteristics between arms. NCF test completion was 82, 76, 63 and 30% at baseline, 6w, 1yr, and 5yr, respectively. RCI-based NCF deterioration was more frequent in Arm 3 compared to Arm 1 at 6 weeks on Delayed Recall (16% vs. 7%, p = 0.023). Patients in Arm 3 evidenced greater z-score decline compared to patients in Arm 1 at 6w on HVLT-R Total Recall [M(SD) Z-score∆ = -0.1(1.0) vs 0.2(0.9), (p = 0.020)] and Delayed Recall [M(SD) Z-score∆ = -0.4(1.5) vs 0.1(1.2), (p = 0.012)]. Mixed effects models identified statistically significant differences in z-scores between Arm 3 and 1 at 6w on Delayed Recall [-0.541 (SE 0.178, p = 0.002)]. A statistically significant difference was observed between Arm 2 and 1 at 6w on TMTB [1.498 (SE 0.626, p = 0.017) favoring Arm 2]. Between arm differences were not seen at any other time point, or on other NCF outcomes. Conclusions: Compared to patients treated with PBRT alone, patients treated with PBRT+STADT+PLNRT exhibited greater worsening in episodic verbal learning and memory processes at 6 weeks after the end of RT, while patients treated with PBRT+STADT exhibited greater improvement in processing speed. The absence of long term or progressive cognitive decline associated with STADT-containing regimens is promising but limited by substantial missing data at year 5. FUNDING This project was supported by grants 10CA180868 (NRG Oncology Operations), U10CA180822 (NRG Oncology SDMC), CTEP from the National Cancer Institute (NCI). Clinical trial information: NCT00567580 .

Do we need to redefine the phoenix criteria after the arrival of the new generation imaging techniques?

e17018 Background: The biochemical recurrence (BCR) criteria are different depending on the primary tumour treatment: PSA ≥0.2 ng/mL after radical prostatectomy (RP) and PSA ≥ 2 ng/mL above the nadir after radiotherapy (RT)[Phoenix criteria]. The latter was established based on the detection of metastasis by conventional imaging tests (CT and bone scanning). Next generation imaging (NGI) techniques (18F-choline PET/CT and specially 18F-PSMA PET/CT), allow detection of metastasis with PSA values much lower than the Phoenix criteria. The purpose of this study is to compare the profile of patients diagnosed with metastatic hormone sensitive prostate cancer (mHSPC) by NGI techniques after BCR according to the primary tumour treatment performed. Methods: Patients diagnosed with mHSPC in our Radiation Oncology Department after BCR between February 2021 and December 2022 were reviewed. All of them underwent NGI: 18F-choline PET/CT if there was BCR following RT or a PSA level > 2 ng/ml after PTR; 18F-PSMA PET/CT if there was BCR after PTR or if 18F-choline PET/CT offered diagnostic uncertainties. Then, were stratified according to primary treatment: PTR (+/- salvage RT to the prostatic bed) vs RT (external or brachytherapy). PSA levels prior to NGI, number of metastases (≤5: oligometastatic vs > 5: polymetastatic) and their location (M1a: exclusive lymph node metastasis, M1b: presence of bone metastasis and M1c: presence of visceral metastasis) were compared. Results: A total of 38 patients were idiagnosed with mHSPC: 42.1% after PTR and 57.9% after RT. PTR group had PSA levels prior to NGI of 1.08 ng/ml, of which 75% were 18F-PSMA PET/CT. Twenty-five per cent of patients in this group were classified as polymetastatic. In RT group the median PSA levels prior to NGI was 3.5 ng/ml, of which 68.2% were 18F-choline PET/CT. The proportion of polymetastatic patients was 50%. The location of metastases in PTR and RT group was: M1a (68.8% vs 59.1%), M1b (31.3% vs 36.4%) and M1c (0% vs 4.5%). Conclusions: The percentage of polymetastatic patients in RT group is double that of PTR group, which is a worse prognostic factor. (4). This difference in the number of metastases is due to the higher PSA levels prior to NGI in RT group, which is directly related to the definition established by the Phoenix criteria(3). Given that NGI techniques can detect metastases with PSA values below the Phoenix criteria, it would be reasonable to redefine it in order to reduce the percentage of polymetastatic patients through earlier detection and thus improve their prognosis.

COMBINED MODALITY ULTRA‐LOW‐DOSE ADAPTIVE RADIOTHERAPY AND RITUXIMAB AS TREATMENT STRATEGY FOR INDOLENT NON‐HODGKIN LYMPHOMAS: THE UT SOUTHWESTERN EXPERIENCE

Introduction: For indolent non-Hodgkin lymphomas (iNHL), ultra-low-dose radiation therapy (ULDRT) with 4 Gy (2 Gy × 2 or “boom-boom”) has demonstrated durable local control (70%), though distal relapses may occur. Concurrent systemic chemotherapy with RT extends PFS but is often avoided due to toxicity. We hypothesize that the combination of adaptive ULDRT and single-agent rituximab results in excellent local and systemic control with minimal toxicity. Methods: We conducted an IRB approved retrospective review of patients with iNHL who were treated with both ULDRT and rituximab (4 weekly doses of 375 mg/m2) as frontline therapy, either concurrently, or within a short interval (median 13 days), at our institution from 2017-2023. Treatment response and disease control (local and distant) were measured. Overall and progression-free survival (OS and PFS) were analyzed using the Kaplan-Meier method. Results: Baseline patient characteristics and treatment sites are shown in Table 1. The overall response rate at first follow up was 21/22 (95%), of which 17 sites (77%) achieved complete response (CR), 4 (18%) partial response (PR), and 1 (5%) stable disease (SD). Of those with PR, 1 had residual disease in-field, 1 out-of-field, and 2 both in- and out-of-field of RT. Repeat ULDRT was given to sites of PR with all achieving CR except for 1 patient with both in and out-of-field PR who declined salvage RT and was managed with active surveillance with SD on last follow up. Two patients experienced mild acute RT-related toxicities (diarrhea and dysgeusia), and 1 patient with Sjogren’s syndrome experienced long-term mild dry mouth. There were no major toxicities associated with rituximab. Of 14/22 initially symptomatic treatment sites, 12/14 (86%) noted resolution after treatment. In our cohort, the 2-year PFS and OS were 86% and 100%, respectively. The median time to relapse was 23 months. Of the patients who relapsed, 1 relapsed in-field, and 2 relapsed both in- and out-of-field of ULDRT. Two of these patients were retreated with ULDRT, while one is undergoing systemic treatment with bendamustine/rituximab. Conclusion: The combination of rituximab and ULDRT demonstrates sustained local and distant disease control with minimal side effects in iNHL. In situations where there is prohibitive toxicity risk for chemotherapy and/or higher radiation doses, this strategy presents a reasonable alternative. Further studies are needed to elucidate potential mechanisms of synergy and define the optimal use of this treatment paradigm. Keywords: combination therapies, indolent non-Hodgkin lymphoma, radiation therapy Conflicts of interests pertinent to the abstract G. Kaur Employment or leadership position: SANOFI, BMS, Janssen, Cellectar, Arcellx Consultant or advisory role Advisory

18F-DCFPyL PSMA-PET affects management of salvage radiotherapy for post-prostatectomy patients with biochemical failure: A matched cohort study.

Our objective was to assess the effect of 18F-DCFPyL prostate-specific membrane antigen (PSMA) positron emission tomography (PET) on the management and outcomes of patients receiving salvage radiotherapy following biochemical failure (BF) post-radical prostatectomy (RP) using a matched cohort analysis. A PSMA-PET cohort of patients with BF post-RP was identified through a prospective registry. Patients from this registry were included if they did not have disease outside of the pelvis and underwent salvage radiotherapy to the prostate and/or pelvis. Case-control matching was performed with a contemporary cohort of patients with BF post-RP without PSMA-PET information. Forty-four patients were included in the PSMA-PET cohort and 80 were analyzed in the non-PSMA-PET cohort. The PSMA-PET cohort had a significantly higher pre-radiotherapy median prostate-specific antigen (PSA) of 0.48 ng/mL compared to 0.20 ng/mL in the non-PSMA-PET cohort (p<0.001), but these levels were similar after matching. The PSMA-PET cohort had a higher proportion of patients receiving radiotherapy to pelvic lymph nodes (n=27 [61.4%] vs. n=16 [20.0%], p<0.001). Median followup was 26 months (interquartile range 18.8-33) for both cohorts. BF-free survival and event-free survival were not significantly different between the two cohorts for all (p=0.662 and >0.99) and matched patients (p=0.808 and 0.808), respectively. Metastasis-free survival was significantly higher in the matched PSMA-PET cohort compared to the matched non-PSMA-PET cohort (p=0.046), although a higher proportion of patients in the non-PSMA-PET cohort underwent PSMA-PET restaging after BF (52% vs. 20%, p=0.08726). Our study showed that patients undergoing PSMA-PET scans after BF post-RP had a higher likelihood of pelvic nodal treatment at the time of salvage RT. Despite higher PSA levels at salvage, we identified no recurrence or survival differences.

Location of Recurrences after Trimodality Treatment for Glioblastoma with Respect to the Delivered Radiation Dose Distribution and Its Influence on Prognosis.

While prognosis of glioblastoma after trimodality treatment is well examined, recurrence pattern with respect to the delivered dose distribution is less well described. Therefore, here we examine the gain of additional margins around the resection cavity and gross-residual-tumor. All recurrent glioblastomas initially treated with radiochemotherapy after neurosurgery were included. The percentage overlap of the recurrence with the gross tumor volume (GTV) expanded by varying margins (10 mm to 20 mm) and with the 95% and 90% isodose was measured. Competing-risks analysis was performed in dependence on recurrence pattern. Expanding the margins from 10 mm to 15 mm, to 20 mm, to the 95%- and 90% isodose of the delivered dose distribution with a median margin of 27 mm did moderately increase the proportion of relative in-field recurrence volume from 64% to 68%, 70%, 88% and 88% (p < 0.0001). Overall survival of patients with in-and out-field recurrence was similar (p = 0.7053). The only prognostic factor significantly associated with out-field recurrence was multifocality of recurrence (p = 0.0037). Cumulative incidences of in-field recurrences at 24 months were 60%, 22% and 11% for recurrences located within a 10 mm margin, outside a 10 mm margin but within the 95% isodose, or outside the 95% isodose (p < 0.0001). Survival from recurrence was improved after complete resection (p = 0.0069). Integrating these data into a concurrent-risk model shows that extending margins beyond 10 mm has only small effects on survival hardly detectable by clinical trials. Two-thirds of recurrences were observed within a 10 mm margin around the GTV. Smaller margins reduce normal brain radiation exposure allowing for more extensive salvage radiation therapy options in case of recurrence. Prospective trials using margins smaller than 20 mm around the GTV are warranted.

Development and Validation of a Multi-institutional Nomogram of Outcomes for PSMA-PET–Based Salvage Radiotherapy for Recurrent Prostate Cancer

Prostate-specific antigen membrane positron-emission tomography (PSMA-PET) is increasingly used to guide salvage radiotherapy (sRT) after radical prostatectomy for patients with recurrent or persistent prostate cancer. To develop and validate a nomogram for prediction of freedom from biochemical failure (FFBF) after PSMA-PET-based sRT. This retrospective cohort study included 1029 patients with prostate cancer treated between July 1, 2013, and June 30, 2020, at 11 centers from 5 countries. The initial database consisted of 1221 patients. All patients had a PSMA-PET scan prior to sRT. Data were analyzed in November 2022. Patients with a detectable post-radical prostatectomy prostate-specific antigen (PSA) level treated with sRT to the prostatic fossa with or without additional sRT to pelvic lymphatics or concurrent androgen deprivation therapy (ADT) were eligible. The FFBF rate was estimated, and a predictive nomogram was generated and validated. Biochemical relapse was defined as a PSA nadir of 0.2 ng/mL after sRT. In the nomogram creation and validation process, 1029 patients (median age at sRT, 70 years [IQR, 64-74 years]) were included and further divided into a training set (n = 708), internal validation set (n = 271), and external outlier validation set (n = 50). The median follow-up was 32 months (IQR, 21-45 months). Based on the PSMA-PET scan prior to sRT, 437 patients (42.5%) had local recurrences and 313 patients (30.4%) had nodal recurrences. Pelvic lymphatics were electively irradiated for 395 patients (38.4%). All patients received sRT to the prostatic fossa: 103 (10.0%) received a dose of less than 66 Gy, 551 (53.5%) received a dose of 66 to 70 Gy, and 375 (36.5%) received a dose of more than 70 Gy. Androgen deprivation therapy was given to 325 (31.6%) patients. On multivariable Cox proportional hazards regression analysis, pre-sRT PSA level (hazard ratio [HR], 1.80 [95% CI, 1.41-2.31]), International Society of Urological Pathology grade in surgery specimen (grade 5 vs 1+2: HR, 2.39 [95% CI, 1.63-3.50], pT stage (pT3b+pT4 vs pT2: HR, 1.91 [95% CI, 1.39-2.67]), surgical margins (R0 vs R1+R2+Rx: HR, 0.60 [95% CI, 0.48-0.78]), ADT use (HR, 0.49 [95% CI, 0.37-0.65]), sRT dose (>70 vs ≤66 Gy: HR, 0.44 [95% CI, 0.29-0.67]), and nodal recurrence detected on PSMA-PET scans (HR, 1.42 [95% CI, 1.09-1.85]) were associated with FFBF. The mean (SD) nomogram concordance index for FFBF was 0.72 (0.06) for the internal validation cohort and 0.67 (0.11) in the external outlier validation cohort. This cohort study of patients with prostate cancer presents an internally and externally validated nomogram that estimated individual patient outcomes after PSMA-PET-guided sRT.

(403) Artificial Urinary Sphincter Implantation for Severe Post-Prostatectomy Incontinence in Setting of Salvage Radiotherapy and Prior Inflatable Penile Prosthesis

Abstract Introduction Artificial urinary sphincter (AUS) implantation is one of the most common treatment options for individuals with severe stress urinary incontinence (SUI), which is a common complication after radical prostatectomy (RP). The modern AUS consists of a urethral cuff, pump, and reservoir, which serves as a replacement for the native incompetent sphincter. There are various surgical approaches for AUS insertion, including transperineal, transscrotal, and abdominal approaches. Objective This video covers the surgical technique for the implantation of an AUS for management of SUI. Notably, this patient underwent RP followed by salvage radiotherapy (XRT) for biochemical recurrence of prostate cancer and had prior inflatable penile prosthesis (IPP) placement. Methods A standard step-by-step surgical technique for placement of an AUS through a perineal incision and additional counter incision to allow for high submuscular placement of the pressure-regulating balloon is demonstrated in this unique case of a patient with prior IPP placement and salvage XRT. Results We highlight a meticulous dissection around the urethra in a case that had a challenging urethral dissection secondary to prior radiotherapy and a prior IPP in the proximal corpora. The AUS pump was successfully placed in the subdartos pouch of the scrotum on the contralateral side to avoid the patient’s prior IPP pump. At the conclusion, a flexible cystourethroscopy showed adequate AUS cuff coaptation and cycling. Conclusions This video covers the step-by-step technique for insertion of an AUS with a transperineal approach in the unique context of a patient with prior IPP placement and XRT. Preoperative counseling, evaluation, and careful intraoperative dissection of key parts of the procedure are critical for successful placement of the AUS, especially in patients who are at high-risk for complications, such as in this case. Disclosure No

Adverse risk factors for salvage radiotherapy outcomes after radical prostatectomy in prostate cancer patients.

To investigate salvage treatment approaches and treatment outcomes in high-risk prostate cancer after radical prostatectomy (RP). In this retrospective, multicenter study, 272 patients who underwent salvage radiotherapy (RT) ± androgen deprivation therapy (ADT) for recurrent prostate cancer after RP between 2007 and 2021 were analysed. Univariate analyses of time to biochemical and clinical relapse after salvage therapies were conducted using Kaplan-Meier plots and log-rank tests. Multivariate analyses were performed using a Cox proportional hazards model to determine the risk factors for disease relapse. Median age was 65 (48-82) years. All patients underwent salvage prostate bed RT. Pelvic lymphatic RT was performed in 66 patients (24.3%) and ADT was included in 158 (58.1%) patients. The median PSA value before RT was 0.35ng/mL. The median follow-up time was 64 (12-180) months. 5-years bRFS, cRFS, and OS were 75.1%, 84.8%, and 94.9% respectively. In multivariate cox regression analysis; seminal vesicle invasion (HR 8.64, 95% CI 3.47-21.48, p < 0.001), pre-RT PSA higher than 0.14ng/mL (HR 3.79, 95% CI 1.47-9.78, p= 0.006), and ≥ 2 positive pelvic lymph nodes (HR 2.50, 95% CI 1.11-5.62, p= 0.027) were found to be unfavorable prognostic factors for bRFS. Salvage RT ± ADT provided 5-years biochemical disease control in 75.1% of patients. Seminal vesicle invasion, ≥ 2 positive pelvic nodes and delayed administration of salvage RT (PSA levels higher than 0.14ng/mL) were found to be adverse risk factors for relapse. Such factors should be taken into account during the decision process on salvage treatment.

Can 68 Ga-PSMA positron emission tomography and multiparametric MRI guide treatment for biochemical recurrence after radical prostatectomy?

To evaluate the role of multiparametric magnetic resonance imaging (mpMRI) and Gallium-68 (68 Ga)-prostate-specific membrane antigen (PSMA) positron emission tomography (PET)/computed tomography (CT) in guiding salvage therapy for patients with biochemical recurrence (BCR) post-radical prostatectomy. Patients were evaluated with paired mpMRI and 68 Ga-PSMA PET/CT scans for BCR (prostate-specific antigen [PSA] >0.2 ng/mL). Patient, tumour, PSA and imaging characteristics were analysed with descriptive statistics. A total of 117 patients underwent paired scans to investigate BCR, of whom 53.0% (62/117) had detectable lesions on initial scans and 47.0% (55/117) did not. Of those without detectable lesions, 8/55 patients proceeded to immediate salvage radiotherapy (sRT) and 47/55 were observed. Of patients with negative imaging who were initially observed, 46.8% (22/47) did not reach threshold for repeat imaging, while 53.2% were rescanned due to rising PSA levels. Of these rescanned patients, 31.9% (15/47) were spared sRT due to proven distant disease, or due to absence of disease on repeat imaging. Of the original 117 patients, 53 (45.3%) were spared early sRT due to absence of disease on imaging or presence of distant disease, while those undergoing delayed sRT still maintained good PSA responses. Of note, patients with high-risk features who underwent sRT despite negative imaging demonstrated satisfactory PSA responses to sRT. Study limitations include the observational design and absence of cause-specific or overall survival data. Our findings support the use of mpMRI and 68 Ga-PSMA PET/CT in guiding timing and necessity of salvage therapy tailored to detected lesions, with potential to reduce unnecessary sRT-related morbidity. Larger or randomized trials are warranted to validate this.

The Longitudinal Course of Prospectively Recorded Patient-reported Outcomes in Prostate Cancer Patients Treated with Surgery and Salvage Radiotherapy

BackgroundPatient-reported outcome measures (PROMs) after prostate cancer (PC) treatment, including both radical prostatectomy (RP) and salvage radiation therapy (SRT), are under-reported. ObjectiveTo investigate PROMs longitudinally from before SRT until 18 mo after SRT for men treated with contemporary treatment modalities. Design, setting, and participantsThis prospective, longitudinal cohort study included 120 men (whole cohort) treated with SRT administered with volumetric modulated arc radiotherapy from 2016 to 2021 at the University Hospital of North Norway. The whole cohort was followed from before SRT until 18 mo after SRT. A subcohort of 48 men was followed from before RP until 18 mo after SRT. Outcome measurements and statistical analysisPROMs were collected with the Expanded Prostate Cancer Index-26 (EPIC-26), covering symptoms of urinary incontinence, urinary irritative, bowel, sexual, and hormonal domains. The domain scores were inquired before RP, 3 mo after RP, before SRT, at SRT termination, and 3 and 18 mo after SRT. We used linear mixed models with repeated measurements design to assess changes in PROMs throughout the treatment period. Results and limitationsThe median age before SRT was 63 yr. For the whole cohort, all five domains worsened at 3 and 18 mo after SRT compared with those before SRT. The estimated mean changes from before SRT to 18 mo after SRT are as follows: urinary incontinence –13.1, urinary irritative function –10.4, bowel –16.8, sexual function –9.1, and hormonal function –20.2 (at clinically important levels for all domains but sexual). For the subcohort, the mean urinary incontinence, bowel, sexual, and hormonal functions were significantly worsened 3 and 18 mo after SRT compared with those before RP at clinically important levels. ConclusionsMen treated for PC report particular increased severity of urinary, bowel, sexual, and hormonal symptoms after SRT compared with baseline status. Patient summaryFor men with prostate cancer, the treatment combination of surgery and salvage radiotherapy worsens urinary incontinence and bowel, sexual, and hormonal functions.

Outcomes of Salvage Therapy for Oropharyngeal Cancer Recurrence Following Upfront Radiation Therapy and Prognostic Factors.

This study aimed to investigate the oncologic outcomes and prognostic factors of salvage treatments in patients with recurrent oropharyngeal squamous cell carcinoma (OPSCC) after radiotherapy (RT)-based treatment. A cancer registry was used to retrieve the records of 337 patients treated with definitive RT or concurrent chemoradiotherapy (CRT) from 2008 to 2018 at a single institution. The poor-responder group (PRG) was defined as patients with residual or recurrent disease after primary treatment, and the oncologic outcomes for each salvage treatment method were analyzed. In addition, prognostic indicators of recurrence-free survival (RFS) and overall survival (OS) were identified in patients who underwent salvage treatment. After initial (C)RT, the PRG comprised 71 of the 337 patients (21.1%): 18 patients had residual disease, and 53 had recurrence after primary treatment (mean time to recurrence 19.5 months). Of these, 63 patients received salvage treatment (surgery 57.2%, re-(C)RT 23.8%, and chemotherapy 19.0%), and the salvage success rate was 47.6% at the last follow-up. The overall 2-year OS for salvage treatments was 56.4% (60.8% for the salvage surgery group and 46.2% for the salvage re-(C)RT). Salvage surgery patients with negative resection margins had better oncologic outcomes than those with close/positive resection margins. Using multivariate analyses, locoregional recurrence and residual disease after primary surgery were associated with poor outcome after salvage treatment. In Kaplan-Meier analyses, p16 status was significantly associated with OS in the initial treatment setting but not in the salvage setting. In recurrent OPSCC after RT-based treatment, successful salvage was achieved in 56.4% patients who had undergone salvage surgery and radiation treatment. Salvage treatment methods should be selected carefully, given recurrence site as a prognostic factor for RFS.

Salvage Radiation Therapy After Radical Prostatectomy: Analysis of Toxicity by Dose-Fractionation in the RADICALS-RT Trial

Emerging data indicate comparable disease control and toxicity of normal postoperative fractionation and moderate hypofractionation radiation therapy (RT) in prostate cancer. In RADICALS-RT, patients were planned for treatment with either 66 Gy in 33 fractions (f) over 6.5 weeks or 52.5 Gy in 20 f over 4 weeks. This non-randomized, exploratory analysis explored the toxicity of these 2 schedules in patients who had adjuvant RT. Information on RT dose was collected in all patients. The Radiation Therapy Oncology Group toxicity score was recorded every 4 months for 2 years, every 6 months until 5 years, then annually until 15 years. Patient-reported data were collected at baseline and at 1, 5, and 10 years using standard measures, including the Vaizey fecal incontinence score (bowel) and the International Continence Society Male Short-Form questionnaire (urinary incontinence). The highest event grade was recorded within the first 2 years and beyond 2 years and compared between treatment groups using the χ² test. Of 634 patients, 217 (34%) were planned for 52.5 Gy/20f and 417 (66%) for 66 Gy/33f. In the first 2 years, grade 1 to 2 cystitis was reported more frequently among the 66 Gy/33f group (52.5 Gy/20f: 20% vs 66 Gy/33f: 30%; P=.04). After 2 years, grade 1 to 2 cystitis was reported in 16% in the 66-Gy group and 9% in the 52.5-Gy group (P=.08). Other toxic effects were similar in the 2 groups, and very few patients had any grade 3 to 4 toxic effects. Patients reported slightly higher urinary and fecal incontinence scores at 1 year than at baseline, but no clinically meaningful differences were reported between the 52.5 Gy/20f and 66 Gy/33f groups. Patient-reported health was similar at baseline and at 1 year and similar between the 52.5 Gy/20f and 66 Gy/33f groups. Severe toxic effects were rare after prostate bed radiation therapy with either 52.5 Gy/20f or 66 Gy/33f. Only modest differences were recorded in toxic effects or in patient-reported outcomes between these 2 schedules.

PD-0566 MRI before salvage radiotherapy after radical prostatectomy in prostate cancer: a case-control study

PD-0566 MRI before salvage radiotherapy after radical prostatectomy in prostate cancer: a case-control study

PD-0567 CT-based radiomic signatures to predict biochemical recurrence after salvage radiotherapy

PD-0567 CT-based radiomic signatures to predict biochemical recurrence after salvage radiotherapy

PO-1284 Comprehensive analysis to predict lymphedema after salvage irradiation in locoregional breast cancer

PO-1284 Comprehensive analysis to predict lymphedema after salvage irradiation in locoregional breast cancer

MO-0872 Circulating tumor cells and efficacy of prostate bed salvage radiotherapy combined with abiraterone

MO-0872 Circulating tumor cells and efficacy of prostate bed salvage radiotherapy combined with abiraterone

PO-1517 Timing of Salvage Radiotherapy After Prostatectomy: From Randomized Trials to the Real World

PO-1517 Timing of Salvage Radiotherapy After Prostatectomy: From Randomized Trials to the Real World

PO-1459 Stereotactic salvage radiotherapy for prostate red relapse, early analysis from a prospective trial

PO-1459 Stereotactic salvage radiotherapy for prostate red relapse, early analysis from a prospective trial

OC-0435 Multi-institutional nomogram for PSMA-PET based salvage radiotherapy in recurrent prostate cancer

OC-0435 Multi-institutional nomogram for PSMA-PET based salvage radiotherapy in recurrent prostate cancer