Radiotherapy For Cancer Research Articles

As-Needed Pilocarpine for Radiation-Induced Xerostomia in Head and Neck Cancers.

This study aimed to evaluate the efficacy of as-needed pilocarpine for the management of radiation-induced xerostomia. Additionally, the study sought to assess the side effects associated with an as-needed regimen. A randomized, double-blinded, placebo-controlled crossover study was conducted on patients who had undergone radiation therapy for head and neck cancers and developed xerostomia. Participants took pilocarpine or placebo as needed for symptom relief at 2 weeks per treatment, which included a one-week washout period. The primary outcome measure was the severity of dry mouth symptoms, quantified using the Xerostomia Inventory (XI). The primary outcome was the change in the XI score. Among the 20 participants who completed the crossover study, there was a significant reduction in XI scores during the treatment phase with pilocarpine compared to the scores during the placebo phase. The mean difference in XI scores was -18.05 (95% CI: -17.17, -6.13, p < 0.001), with a-49.77 ± 3.22% change (p < 0.001). Only one participant withdrew due to pilocarpine side effects. As-needed pilocarpine administration is effective in relieving symptoms of radiation-induced xerostomia, with fewer side effects and reduced treatment costs compared to fixed-dose regimens. This study guides the potential shift toward flexible dosing strategies in clinical practice, promoting enhanced patient-centered, tailored care and adherence. According to the Oxford Center for Evidence-Based Medicine 2011 level of evidence guidelines Laryngoscope, 134:4542-4548, 2024.

A comprehensive evaluation of toxicity after radical hysterectomy or trachelectomy and postoperative pelvic intensity-modulated radiation therapy for cervical cancer

A comprehensive evaluation of toxicity after radical hysterectomy or trachelectomy and postoperative pelvic intensity-modulated radiation therapy for cervical cancer

Hypofractionated short-course radiation therapy for recurrent ovarian cancer: A retrospective cohort study

Hypofractionated short-course radiation therapy for recurrent ovarian cancer: A retrospective cohort study

Comparative Cardiovascular Risks of Radical Prostatectomy and External Beam Radiation Therapy in Early-Stage Prostate Cancer: A Comprehensive Retrospective Analysis.

The risk of cardiac disease mortality has recently become a focal point of concern within the medical community for patients with prostate cancer (PCa). Given that radical prostatectomy (RP) and external beam radiation therapy (EBRT) are the main treatment modalities for localized PCa, their specific impact on cardiovascular-specific mortality (CSM) remains unclear. This study explored the specific effects of RP and EBRT on CSM risk to guide clinical treatment decisions. Data from patients aged 45-74years, who were diagnosed with T1-2N0M0 stage PCa from the SEER database (2010-2015), were used. Multivariate statistical methods, including propensity score matching (PSM), competing risk regression, COX regression analysis, and Fine-Gray testing, were applied to assess the impact of RP and EBRT on CSM risk. Among 146,082 T1-2 stage PCa patients, cardiac disease emerged as the primary cause of death, surpassing PCa itself. Multifactorial COX regression and competing risk regression analyses indicated that local treatments do not increase CSM risk. Further analysis revealed a significant increase in CSM risk for patients undergoing only EBRT compared with those undergoing only RP (hazard ratio [HR] = 2.71, 95% confidence interval [CI] 1.96-3.74, P < 0.001), with subsequent PSM adjustment, further confirming a significantly reduced risk in the RP treatment group (HR 0.23, 95% CI 0.13-0.40, P < 0.001). T1-2 stage PCa patients face a significant risk of CSM, with RP offering a potential advantage over EBRT in reducing this risk. These findings encourage clinicians to comprehensively consider the potential impact on cardiac health when formulating treatment plans, providing crucial guidance for optimizing treatment strategies.

Validation of different automated segmentation models for target volume contouring in postoperative radiotherapy for breast cancer and regional nodal irradiation

IntroductionTarget volume delineation is routinely performed in postoperative radiotherapy (RT) for breast cancer patients, but it is a time-consuming process. The aim of the present study was to validate the quality, clinical usability and institutional-specific implementation of different auto-segmentation tools into clinical routine. MethodsThree different commercially available, artificial intelligence-, ESTRO-guideline-based segmentation models (M1-3) were applied to fifty consecutive reference patients who received postoperative local RT including regional nodal irradiation for breast cancer for the delineation of clinical target volumes: the residual breast, implant or chestwall, axilla levels 1 and 2, the infra- and supraclavicular regions, the interpectoral and internal mammary nodes. Objective evaluation metrics of the created structures were conducted with the Dice similarity index (DICE) and the Hausdorff distance, and a manual evaluation of usability. ResultsThe resulting geometries of the segmentation models were compared to the reference volumes for each patient and required no or only minor corrections in 72 % (M1), 64 % (M2) and 78 % (M3) of the cases. The median DICE and Hausdorff values for the resulting planning target volumes were 0.87–0.88 and 2.96–3.55, respectively. Clinical usability was significantly correlated with the DICE index, with calculated cut-off values used to define no or minor adjustments of 0.82–0.86. Right or left sided target and breathing method (deep inspiration breath hold vs. free breathing) did not impact the quality of the resulting structures. ConclusionArtificial intelligence-based auto-segmentation programs showed high-quality accuracy and provided standardization and efficient support for guideline-based target volume contouring as a precondition for fully automated workflows in radiotherapy treatment planning.

Elective pelvic nodal irradiation in the setting of ultrahypofractionated versus moderately hypofractionated and conventionally fractionated radiotherapy for prostate cancer: Outcomes from 3 prospective clinical trials

Background and purposeData is needed regarding the use of ultrahypofractionated radiotherapy (UHRT) in the context of prostate cancer elective nodal irradiation (ENI), and how this compares to conventionally fractionated radiotherapy (CFRT) ENI with CFRT or moderately hypofractionated radiotherapy (MHRT) to the prostate. Materials and methodsBetween 2011–2019, 3 prospective clinical trials of unfavourable intermediate or high-risk prostate cancer receiving CFRT (78 Gy in 39 fractions to prostate; 46 Gy in 23 fractions to pelvis), MHRT (68 Gy in 25 fractions to prostate; 48 Gy to pelvis), or UHRT (35–40 Gy in 5 fractions to prostate +/- boost to 50 Gy to intraprostatic lesion; 25 Gy to pelvis) were conducted. Primary endpoints included biochemical failure (Phoenix definition), and acute and late toxicities (CTCAE v3.0/4.0). ResultsTwo-hundred-forty patients were enrolled: 90 (37.5 %) had CFRT, 90 (37.5 %) MHRT, and 60 (25 %) UHRT. Median follow-up time was 71.6 months (IQR 53.6–94.8). Cumulative incidence of biochemical failure (95 % CI) at 5-years was 11.7 % (3.5–19.8 %) for CFRT, 6.5 % (0.8–12.2 %) MHRT, and 1.8 % (0–5.2 %) UHRT, which was not significantly different between treatments (p = 0.38). Acute grade ≥ 2 genitourinary toxicity was significantly worse for UHRT versus CFRT and MHRT, but not for acute grade ≥ 3 genitourinary, or acute gastrointestinal toxicities. UHRT was not associated with worse late toxicities. ConclusionENI with UHRT resulted in similar oncologic outcomes to CFRT ENI with prostate CFRT/MHRT, with worse acute grade ≥ 2 GU toxicity but no differences in late toxicity. Randomized phase 3 trials of ENI using UHRT techniques are much anticipated.

Friday, July 12, 20241:30 PM - 2:45 PM PL01 Presentation Time: 1:30 PM: A Randomized Comparison of LDR or HDR Brachytherapy Boost Combined with Pelvic External Beam Radiation for Unfavorable Intermediate or High-Risk Prostate Cancer. Efficacy Results at Median 6 Years Follow Up

Friday, July 12, 20241:30 PM - 2:45 PM PL01 Presentation Time: 1:30 PM: A Randomized Comparison of LDR or HDR Brachytherapy Boost Combined with Pelvic External Beam Radiation for Unfavorable Intermediate or High-Risk Prostate Cancer. Efficacy Results at Median 6 Years Follow Up

The role of adjuvant chemotherapy among patients who undergo preoperative radiation in endometrial cancer: An NCDB study

The role of adjuvant chemotherapy among patients who undergo preoperative radiation in endometrial cancer: An NCDB study

Contact X-ray Brachytherapy as a sole treatment in selected patients with early rectal cancer – Multi-centre study

Background and purposeRadical surgery is the standard of care for early rectal cancer. However, alternative organ-preserving approaches are attractive, especially in frail or elderly patients as these avoid surgical complications. We have assessed the efficacy of sole Contact X-ray Brachytherapy (CXB) treatment in stage-1 rectal cancer patients who were unsuitable for or declined surgery. Materials and methodsThis retrospective multi-centre study (2009–2021) evaluated 76 patients with T1/2-N0-M0 rectal adenocarcinomas who were treated with CXB alone. Outcomes were assessed for the entire cohort and sub-groups based on the T-stage and the criteria for receiving CXB alone; Group A: patients who were fit enough for surgery but declined, Group B: patients who were high-risk for surgery and Group C: patients who had received prior pelvic radiation for a different cancer. ResultsWith a median follow-up of 26(IQR:12–49) months, initial clinical Complete Response (cCR) was 82(70–93)% with rates of local regrowth 18(8–29)%, 3-year actuarial local control (LC) 84(75–95)%, distant relapse 3 %, and no nodal relapse. 5-year disease-free survival (DFS) and overall survival (OS) were 66(48–78)% and 58(44–75)%. Lower OS was observed in Groups B [HR:2.54(95 %CI:1.17, 5.59), p = 0.02] and C [HR:2.75(95 %CI:1.15, 6.58), p = 0.03]. Previous pelvic radiation predicted lower cCR and OS. The main toxicity was G1-2 rectal bleeding (26 %) and symptoms of impaired anal sphincter function were not reported in any patients. ConclusionCXB treatment alone achieved a high cCR rate with satisfactory LC and DFS. Inferior oncological outcomes were observed in patients who had received prior pelvic radiotherapy. CXB alone, with its favourable toxicity profile and avoidance of general anaesthesia and surgery risks, therefore, can be considered for patients who are unsuitable for or refuse surgery.

Prediction of radiation proctitis in cervical cancer radiotherapy using MRI-based radiomics

Prediction of radiation proctitis in cervical cancer radiotherapy using MRI-based radiomics

Mechanistic study of EPHB2 affecting the sensitivity of cervical cancer radiotherapy by regulating autophagy through AKT/mTOR pathway

Mechanistic study of EPHB2 affecting the sensitivity of cervical cancer radiotherapy by regulating autophagy through AKT/mTOR pathway

Prediction of radiation proctitis in cervical cancer radiotherapy using MRI-based radiomics

Prediction of radiation proctitis in cervical cancer radiotherapy using MRI-based radiomics

Procedural findings and follow-up results of catheter ablation of atrial fibrillation in patients after radiation therapy for breast cancer

Abstract Backround Data on breast cancer radiation therapy (RT) associated atrial cardiomyopathy and its potential role in the pathophysiology of atrial fibrillation (AF) is very limited. Objectives To investigate the effect of breast cancer radiotherapy (RT) on atrial cardiomyopathy and its possible role in the pathophysiology of atrial fibrillation. What is the therapeutic success of antral pulmonary vein isolation (PVI) with possible substrate modifications (CFAE) in patients with breast cancer radiation therapy and paroxysmal or persistent atrial fibrillation. Methods We searched the institution’s data base for patients who received RT for breast cancer and underwent subsequently 3D mapping guided AF ablation. Intraprocedural mapping data and short- and long-term results of ablation were evaluated according to "no low voltage" and "low voltage" present. Low voltage amplitudes in bipolar electrograms were defined as &amp;lt;0.5 mV for endocardial maps created during SR and &amp;lt;0.3mV during AF. Ablation strategy comprised pulmonary vein isolation (PVI) ± additional substrate modification according to the mapping results. Follow Up (FU) was evaluated using repetitive 7-days Holter ECG and clinical visits. Results We included 45 patients (all female, 70.9±7.2 years) with paroxysmal or persistent AF (n=18 and n=27). In 3D mapping, 60% of the patients (27/45) showed left atrial low voltage (LV group) with the majority showing low voltage in the anterior wall of the left atrium (LA) in 18 of 45 patients (40%). PVI with ablation of complex fractionated signals (CFAE) was predominantly performed (18/27). After one ablation, 33.3% (9) of the patients in the LV group were recurrence-free and after an average of 1.9 ablations, freedom from recurrence was achieved in 21 patients with low voltage (77.8%). In 18 patients, no low voltage was detected (NLV group) and PVI only was performed in the majority (14/18). In this NLV group, 61.1% (11) of the patients were recurrence-free after one ablation and freedom from recurrence was achieved in 72.2% (13) after an average of 1.2 ablations. Conclusion Thoracic radiation therapy in patients with breast cancer can lead to low voltage in the LA with the predominant low voltage location being the anterior wall of the LA. An extended ablation strategy (PVI &amp; CFAE) can show good treatment options in these patients with atrial fibrillation, with high freedom from recurrence after a mean of two ablation procedures.Freedom from recurrence after ablationCharacteristics of left atrium (LA)

The intra-tumoral microbiome as a potential biomarker of response to external beam radiation therapy in cervical cancer

BackgroundWe aimed to determine the potential predictive value of the intra-tumoral microbiome as a marker of the response to external beam radiation therapy (EBRT) in cervical cancer (CC).MethodsA prospective longitudinal trial of 36 CC patients receiving pelvic radiotherapy was designed to investigate microbial characteristic signatures and diversity (alpha and beta) of multiple sites (tumor, vaginal, gut, urethral, and oral) in the superior response (SR) and inferior response (IR) groups of CC patients by 16S rRNA sequencing. Utilized the least absolute shrinkage and selection operator (LASSO) logistic regression method to analyze clinicopathological factors that potentially influenced the efficacy of EBRT. LEfSe analysis highlighted the microbiome features that best distinguished the categorized patient samples. Selected parameters were validated with Spearman correlation analysis, receiver operating characteristic (ROC) area under the curve (AUC) analysis and Kaplan-Meier survival analysis.ResultsFirstly, in our cohort, LASSO logistic regression analysis revealed no association between clinicopathological factors and EBRT efficacy. Subsequently, we employed 16S rRNA sequencing to compare microbiome differences across multiple sites and their correlations with major clinicopathological factors. We discovered that the intra-tumoral microbiome was independent of clinicopathologic features and represented the most direct and reliable reflection of the microbial differences between the SR and IR groups. We found lower alpha diversity in the tumor microbiome of SR group and identified the most relevant microbiome taxa (Bifidobacteriaceae, Beijerinckiaceae, and Orbaceae) associated with the efficacy of the response to EBRT in CC patients. We then conducted ROC analysis, finding that specific microbial taxa had an AUC of 0.831 (95% CI, 0.667–0.995), indicating the potential of these taxa as biomarkers for predicting EBRT efficacy. Kaplan-Meier survival analysis showed a better prognosis for patients with lower alpha diversity and higher relative abundance of Bifidobacteriaceae.ConclusionsOur data suggested that intra-tumoral specific microbiome taxa and lower alpha diversity may play an important role in the CC patient sensitivity to EBRT and offer novel potential biomarkers for predicting the response to EBRT efficacy.

Intraoperative Radiation Therapy for Recurrent Cervical and Endometrial Cancer: Predicting Morbidity and Mortality in a Contemporary Cohort

Background/Objectives: Our objective was to describe the use of intraoperative radiation therapy (IORT) for the treatment of recurrent/persistent cervical or endometrial cancer and assess predictors of postoperative complications and 3-year mortality. Methods: In this multi-site retrospective study, data were abstracted for recurrent/persistent endometrial or cervical cancer patients who underwent IORT from June 2004 to May 2021. Complications were graded on the six-point Accordion scale. Variables associated with complications were analyzed with univariate logistic regression, while variables associated with death within 3 years were analyzed with Cox proportional hazards modeling. Survival was analyzed with the Kaplan–Meier method. Results: Eighty patients had planned IORT for recurrent/persistent endometrial (n = 35) or cervical cancer (n = 45). The mean age of the cohort was 56.8 years (SD = 13.7), and the median disease-free interval from primary disease to recurrence was 20.0 months (IQR 10.0–63.1). The overall survival at 3 years was 48.6% (95% CI: 38.3–61.6%) with a median survival of 2.8 years. Within 30 days postoperative, 16 patients (20.1%) had grade 3–5 complications and one death (1.3%) occurred. Factors associated with grade 3+ complication included ECOG PS 2–3 (OR 18.00, p = 0.04), neoadjuvant chemotherapy and/or immunotherapy (OR 6.98, p &lt; 0.01), and pelvic sidewall involvement (OR 8.80, p = 0.04). Factors associated with death within 3 years of surgery included ECOG PS 2–3 (HR 8.97, p &lt; 0.01), neoadjuvant chemotherapy and/or immunotherapy (HR 2.34, p = 0.03), whether exenteration was performed (HR 2.64, p = 0.01), and positive resection margin (HR 3.37, p &lt; 0.01). Conclusions: In well-selected patients, IORT is a feasible and safe option for the treatment of recurrent/persistent gynecologic malignancy with an appreciable survival benefit.

Hypofractionated radiotherapy with simultaneous integrated boost for localized prostate cancer patients: effects on immune system and prediction of toxicity

BackgroundThe other side of radiotherapy (RT), in addition to the cytotoxic effect, is the ability to modulate the immune system in terms of activation or suppression, also depending on the dose and fractionation delivered. This immune RT effect can be detected both locally in the irradiated tumor site and in the peripheral blood. The aim of this study was to assess the consequence of pelvic irradiation on peripheral immune cells and cytokine secretions in localized prostate cancer (PC) patients undergoing pelvic irradiation with a simultaneous moderately hypofractionated prostate/prostate bed boost by Volumetric Modulated Arc Therapy (VMAT). Furthermore, we analyzed whether there was a correlation between these peripheral immune parameters and acute and late genitourinary (GU) and gastrointestinal (GI) toxicity.MethodsThirty-eight PC patients were treated with pelvis irradiation (dose per fraction 1.8 Gy) and simultaneous hypofractionated (median dose per fraction: 2.7 Gy) prostate/prostate bed boost. A longitudinal analysis was performed for 12 months on peripheral blood to assess changes in 9 different lymphocyte subpopulations by flow cytometry and 10 circulating cytokines by Multiplex Luminex assay and ELISA.ResultsOur analysis revealed that basal IFN-γ serum values were significantly lower in the definitive (curative intent for patients with prostate) patient group respect to the post-operative one. All the lymphocyte subsets and IFN-α, IFN-β and Il-2 peripheral concentrations displayed significant variations between the different time points considered. The immune cell population that suffers the greatest RT toxicity in the blood was B lymphocyte. We found an interesting correlation between basal TGF-β1 and late GU toxicity. In particular, TGF-β1 concentrations before RT were significantly higher in patients that experienced grade 2-3 of late GU toxicity, respect to grade 0-1. Exploring possible correlations between some clinical/biological findings and radiation planning parameters, we found no statistical significance.ConclusionsOur study analyzed, in the context of hypofractionated radiotherapy in prostate cancer, different parameters of the peripheral immune system. We have highlighted longitudinally the peripheral behavior of the different lymphocyte subpopulations and of a group of 10 cytokines during the first year after RT. One of the analyzed cytokines, such as TGF-β1, has proven to be promising predictive factor of severe late GU toxicity.

Are novel ASCVD risk factors more prevalent in young middle eastern women who have classical risk factors

Abstract Introduction Urbanization is an important contributor to atherosclerotic cardiovascular disease (ASCVD) in the Middle East, especially in the younger age groups. There is a scarcity of data on clinical profiles and cardiovascular risk factors (RFs) in urban young women compared with those who reside in rural areas in this region. Purpose To study the demographic and clinical profiles and prevalence of traditional and novel CV RFs in a cohort study of young urban Middle Eastern women compared with those in rural areas. Methods The prevalence of 19 traditional and novel cardiovascular RFs were compared in urban vs. rural young women residents (18-50 years of age), who were enrolled in 12 centers (August 2020 to October 2023). Results Of 627 young women enrolled (mean age 44.2 ± 5.1 years old), 463 (74%) were urban residents and 164 (26%) were rural residents. ASCVD was diagnosed in 32% of urban and 37.3% of rural young women. Table shows the prevalence of traditional and novel, sex-specific RFs with significant differences in the 2 groups. Other RFs with no significant differences included hypertension, diabetes and gestational diabetes, preterm delivery, persistent weight gain after delivery, radiation for breast cancer, and polycystic ovary syndrome. Conclusion In this cohort of Middle Eastern young women, despite heterogeneity, those who were urban residents had worse clinical profiles with higher prevalence of certain classical and sex-specific risk factors.

Characteristics and outcomes of patients with a history of cancer enrolled in our prospective HFpEF registry

Abstract Background Along with the aging population, the incidence of concomitant heart failure with preserved ejection fraction (HFpEF) and cancer, is increasing. However, little is known about the typical characteristics of patients with both HFpEF and a history of oncologic disease. Aim We aimed to characterize the distinctive characteristics and outcomes of patients with a history of cancer within a prospective HFpEF registry. Methods We analyzed data from 491 unselected HFpEF patients from our tertiary university center between 2010 and 2022 and followed the patients until 2023. Laboratory parameters and comorbidities were assessed. Patients were categorized into those with and without a history of cancer, including various malignancies, survivors of childhood cancer, radiation therapy, with or without chemotherapy. Kaplan-Meier estimates were used to explore the association between cancer history, as well as previous radiotherapy, and a combined endpoint of heart failure hospitalization and/or all-cause death. Results In this analysis of 491 HFpEF patients, a total of 101 patients (21%); had a history of cancer [mean age 74±7 years; female 72 (72%), male 29 (29%)]. The median time from cancer diagnosis to the initial HFpEF visit was 7.0 years (IQR 13-0.5 years). The most prevalent primary cancer sites included the chest wall (32%) comprising 4 adenocarcinomas of the lung and 28 cases of breast cancer, followed by the gastric (28%), urogenital system (18%), hematologic and lymphatic system (16%), cancers located at the head and neck (5%) and endocrine malignancies (1%). Radiotherapy (39%) and chemotherapy (26%) were common. Notably, no significant differences were observed, between patients with or without a history of cancer, in terms of median NT-proBNP levels [1037 (IQR 416-2075) vs. 1060 pg/ml (IQR 462-2013)] and the frequency of key cardiovascular comorbidities (all p&amp;gt;0.05, see Table 1). Over the study period [median follow-up 50 months (IQR 18-76)], 64 (64%) of cancer patients met the combined endpoint, with no statistically significant difference in outcomes between HFpEF patients with and without a cancer history (log-rank p=0.222, see Figure 1). Furthermore, there was no significant difference in the combined endpoint between patients who had undergone radiotherapy and those without (log-rank p=0.162). Conclusion Our findings highlight a high coexistence of cancer and HFpEF, which can frequently occur after oncology therapies. The data suggest that the presence of a history of cancer or previous radiotherapy did not significantly impact overall outcomes in HFpEF patients compared to those without cancer during the study period. Further research is needed to characterize patients with both disease entities in detail. Due to modern cardiovascular therapy in a university and cardio-oncology clinic setting, outcomes for cancer patients appear better than expected.

Mathematical Modeling Unveils Optimization Strategies for Targeted Radionuclide Therapy of Blood Cancers.

Targeted radionuclide therapy is based on injections of cancer-specific molecules conjugated with radioactive nuclides. Despite the specificity of this treatment, it is not devoid of side-effects limiting its use and is especially harmful for rapidly proliferating organs well perfused by blood, like bone marrow. Optimization of radioconjugates administration accounting for toxicity constraints can increase treatment efficacy. Based on our experiments on disseminated multiple myeloma mouse model treated by 225Ac-DOTA-daratumumab, we developed a mathematical model which investigation highlighted the following principles for optimization of targeted radionuclide therapy. 1) Nuclide to antibody ratio importance. The density of radioconjugates on cancer cells determines the density of radiation energy deposited in them. Low labeling ratio as well as accumulation of unlabeled antibodies and antibodies attached to decay products in the bloodstream can mitigate cancer radiation damage due to excessive occupation of specific receptors by antibodies devoid of radioactive nuclides. 2) Cancer binding capacity-based dosing. The total number of specific receptors on cancer cells is a critical factor for treatment optimization, which estimation may allow increasing treatment efficacy close to its theoretical limit. Injection of doses significantly exceeding cancer binding capacity should be avoided since radioconjugates remaining in the bloodstream have negligible efficacy to toxicity ratio. 3) Particle range-guided multi-dosing. The use of short-range particle emitters and high-affinity antibodies can allow for robust treatment optimization via initial saturation of cancer binding capacity, enabling redistribution of further injected radioconjugates and deposited dose towards still viable cells that continue expressing specific receptors.

Mortality rates in radical cystectomy patients with bladder cancer after radiation therapy for prostate cancer.

To conduct a population-based study examining cancer-specific mortality (CSM) and other-cause mortality (OCM) differences in patients with radiation-induced secondary bladder cancer (RT-BCa) vs those with primary bladder cancer (pBCa) undergoing radical cystectomy (RC). Within the Surveillance, Epidemiology, and End Results database (2004-2020), we identified patients with T2-4N0-3M0 bladder cancer treated with RC, who had previously been treated with external beam radiation therapy (EBRT) or brachytherapy for prostate cancer, as well as patients with T2-4N0-3M0 pBCa treated with RC. Cumulative incidence plots and multivariable competing risks regression (CRR) models were used to assess CSM after additional adjustment for OCM. The same methodology was then repeated based on organ-confined (OC: T2N0M0) and non-organ-confined (NOC: T3-4 and/or N1-3) disease. Of 9957 RC patients, RT-BCa was identified in 347 (3%) compared with 9610 (97%) who had pBCa. In multivariable CRR models, no CSM differences were recorded in the overall comparison (P = 0.8), nor in sub-groups based on OC and NOC disease (P = 0.8 and 0.7, respectively). Conversely, multivariable CRR models identified RT-BCa as an independent predictor of 1.3-fold higher OCM in the overall cohort and of 1.5-fold higher OCM in those with NOC disease. In a sensitivity analysis of patients with NOC disease, EBRT was associated with higher OCM rates (hazard ratio 1.5). By contrast, OCM rates were not different in those with OC disease (P = 0.8). Our study showed that RC for RT-BCa was associated with similar CSM rates as RC for pBCa, regardless of disease stage. However, patients who had undergone EBRT exhibited significantly higher OCM in the NOC sub-group.