Assessment of Proton Beam Therapy Use Among Patients With Newly Diagnosed Cancer in the US, 2004-2018.

Importance: Proton beam therapy (PBT) is a potentially superior technology to photon radiotherapy for tumors with complex anatomy, those surrounded by sensitive tissues, and childhood cancers. Objective: To assess patterns of use of PBT according to the present American Society of Radiation Oncology (ASTRO) clinical indications in the US. Design, Setting, and Participants: Individuals newly diagnosed with cancer between 2004 and 2018 were selected from the National Cancer Database. Data analysis was performed from October 4, 2021, to February 22, 2022. ASTRO's Model Policies (2017) were used to classify patients into group 1, for which health insurance coverage for PBT treatment is recommended, and group 2, for which coverage is recommended only if additional requirements are met. Main Outcomes and Measures: Use of PBT. Results: Of the 5 919 368 patients eligible to receive PBT included in the study, 3 206 902 were female (54.2%), and mean (SD) age at diagnosis was 62.6 (12.3) years. Use of PBT in the US increased from 0.4% in 2004 to 1.2% in 2018 (annual percent change [APC], 8.12%; P < .001) due to increases in group 1 from 0.4% in 2010 to 2.2% in 2018 (APC, 21.97; P < .001) and increases in group 2 from 0.03% in 2014 to 0.1% in 2018 (APC, 30.57; P < .001). From 2010 to 2018, among patients in group 2, PBT targeted to the breast increased from 0.0% to 0.9% (APC, 51.95%), and PBT targeted to the lung increased from 0.1% to 0.7% (APC, 28.06%) (P < .001 for both). Use of PBT targeted to the prostate decreased from 1.4% in 2011 to 0.8% in 2014 (APC, -16.48%; P = .03) then increased to 1.3% in 2018 (APC, 12.45; P < .001). Most patients in group 1 treated with PBT had private insurance coverage in 2018 (1039 [55.4%]); Medicare was the most common insurance type among those in group 2 (1973 [52.5%]). Conclusions and Relevance: The findings of this study show an increase in the use of PBT in the US between 2004 to 2018; prostate was the only cancer site for which PBT use decreased temporarily between 2011 and 2014, increasing again between 2014 and 2018. These findings may be especially relevant for Medicare radiation oncology coverage policies.

Proton versus photon-based radiation therapy for prostate cancer: emerging evidence and considerations in the era of value-based cancer care.

BACKGROUND: Advances in radiation technology have transformed treatment options for patients with localized prostate cancer. The evolution of three-dimensional conformal radiation therapy and intensity-modulated radiation therapy (IMRT) have allowed physicians to spare surrounding normal organs and reduce adverse effects. The introduction of proton beam technology and its physical advantage of depositing its energy in tissue at the end-of-range maximum may potentially spare critical organs such as the bladder and rectum in prostate cancer patients. Data thus far are limited to large, observational studies that have not yet demonstrated a definite benefit of protons over conventional treatment with IMRT. The cost of proton beam treatment adds to the controversy within the field. METHODS: We performed an extensive literature review for all proton treatment-related prostate cancer studies. We discuss the history of proton beam technology, as well as its role in the treatment of prostate cancer, associated controversies, novel technology trends, a discussion of cost-effectiveness, and an overview of the ongoing modern large prospective studies that aim to resolve the debate between protons and photons for prostate cancer. RESULTS: Present data have demonstrated that proton beam therapy is safe and effective compared with the standard treatment options for prostate cancer. While dosimetric studies suggest lower whole-body radiation dose and a theoretically higher relative biological effectiveness in prostate cancer compared with photons, no studies have demonstrated a clear benefit with protons. CONCLUSIONS: Evolving trends in proton treatment delivery and proton center business models are helping to reduce costs. Introduction of existing technology into proton delivery allows further control of organ motion and addressing organs-at-risk. Finally, the much-awaited contemporary studies comparing photon with proton-based treatments, with primary endpoints of patient-reported quality-of-life, will help us understand the differences between proton and photon-based treatments for prostate cancer in the modern era.

Clinical needs assessment for sexual health among cancer patients receiving pelvic radiation: Implications for development of a radiation oncology sexual health clinic.

BACKGROUND: Cancer patients treated with pelvic radiation therapy (RT) often experience sexual health-related side effects during and following treatment. A clinical needs assessment was used to evaluate sexual health needs and to determine how needs differed between patients receiving and who had completed RT. METHODS AND MATERIALS: A questionnaire was used to evaluate sexual health needs among patients treated with pelvic RT. All answers were rated using a 4-point Likert scale. Convenience sampling was used, and patients were stratified by whether they were on-treatment or in follow-up. Charts were reviewed for demographic, diagnostic, and treatment information. Pearson's χ2 test and logistic regression analysis were used to analyze the associations between sexual health-related topics and clinical variables. RESULTS: A total of 107 of 109 (98%) invited patients completed the questionnaire (46 females, 61 males; 52 undergoing RT, 54 completed RT). Most (75%) reported some degree of change in sexual health from the effects of cancer and/or treatment; 22% and 28% reported "quite a bit" or "very much" change, respectively. Sixty-nine percent reported that they experienced some degree of distress from sexual health changes (28% reported "very much" or "quite a bit" of distress). Seventy-six percent "agreed" or "strongly agreed" that they were interested in access to a multidisciplinary sexual health clinic (MSHC). Compared with patients currently receiving RT, patients in follow-up were significantly more likely to report worsening degrees of "change" (P = .008) and "distress" (P = .04) and to express interest in having access to an MSHC (P = .03). CONCLUSION: The majority of patients receiving pelvic RT reported a change in sexual health with associated distress, with more reports among those in follow-up. Patients undergoing pelvic RT expressed a high interest in attending a radiation oncology MSHC. Our findings emphasize the important role radiation oncologists can play in the quality of life of our patients.

Incidence, Clinicopathological Risk Factors, Management and Outcomes of Nonmuscle Invasive Recurrence after Complete Response to Trimodality Therapy for Muscle Invasive Bladder Cancer.

PURPOSE: We describe the incidence, clinicopathological risk factors, management and outcomes of recurrent nonmuscle invasive bladder cancer after a complete response to trimodality therapy of muscle invasive bladder cancer. MATERIALS AND METHODS: We retrospectively reviewed the records of 342 patients with cT2-4aN0M0 muscle invasive bladder cancer and a complete response after trimodality therapy from 1986 to 2013. Using competing risks analyses we examined the association between baseline clinicopathological variables and nonmuscle invasive bladder cancer outcomes. Kaplan-Meier and the generalized Fleming-Harrington test were used to compare disease specific and overall survival. RESULTS: At a median followup of 9 years nonmuscle invasive bladder cancer recurred in 85 patients (25%) who had had a complete response. On Kaplan-Meier analysis baseline carcinoma in situ was associated with recurrent nonmuscle invasive bladder cancer (p = 0.02). However, on multivariate analysis carcinoma in situ and other baseline clinicopathological characteristics did not predict such recurrence. Patients with recurrent nonmuscle invasive bladder cancer had worse 10-year disease specific survival than those without recurrence (72.1% vs 78.4%, p = 0.002), although overall survival was similar (p = 0.66). Of the 39 patients (46%) who received adjuvant intravesical bacillus Calmette-Guérin 29 (74%) completed induction therapy and 19 (49%) reported bacillus Calmette-Guérin toxicity. Three-year recurrence-free and progression-free survival after induction bacillus Calmette-Guérin was 59% and 63%, respectively. CONCLUSIONS: After a complete response to trimodality therapy nonmuscle invasive bladder cancer recurred in 25% of patients, developing in some of them more than a decade after trimodality therapy. No baseline clinicopathological characteristics were associated with such recurrence after a complete response. Patients with nonmuscle invasive bladder cancer recurrence had worse disease specific survival than those without such recurrence but similar overall survival. Adjuvant intravesical bacillus Calmette-Guérin had a reasonable toxicity profile and efficacy in this population. Properly selected patients with recurrent nonmuscle invasive bladder cancer after a complete response may avoid immediate salvage cystectomy.

Promoting the Appropriate Use of Advanced Radiation Technologies in Oncology: Summary of a National Cancer Policy Forum Workshop.

PURPOSE: Leaders in the oncology community are sounding a clarion call to promote "value" in cancer care decisions. Value in cancer care considers the clinical effectiveness, along with the costs, when selecting a treatment. To discuss possible solutions to the current obstacles to achieving value in the use of advanced technologies in oncology, the National Cancer Policy Forum of the National Academies of Sciences, Engineering, and Medicine held a workshop, "Appropriate Use of Advanced Technologies for Radiation Therapy and Surgery in Oncology" in July 2015. The present report summarizes the discussions related to radiation oncology. METHODS AND MATERIALS: The workshop convened stakeholders, including oncologists, researchers, payers, policymakers, and patients. Speakers presented on key themes, including the rationale for a value discussion on advanced technology use in radiation oncology, the generation of scientific evidence for value of advanced radiation technologies, the effect of both scientific evidence and "marketplace" (or economic) factors on the adoption of technologies, and newer approaches to improving value in the practice of radiation oncology. The presentations were followed by a panel discussion with dialogue among the stakeholders. RESULTS: Challenges to generating evidence for the value of advanced technologies include obtaining contemporary, prospective, randomized, and representative comparative effectiveness data. Proposed solutions include the use of prospective registry data; integrating radiation oncology treatment, outcomes, and quality benchmark data; and encouraging insurance coverage with evidence development. Challenges to improving value in practice include the slow adoption of higher value and the de-adoption of lower value treatments. The proposed solutions focused on engaging stakeholders in iterative, collaborative, and evidence-based efforts to define value and promote change in radiation oncology practice. Recent examples of ongoing or successful responses to the discussed challenges were provided. CONCLUSIONS: Discussions of "value" have increased as a priority in the radiation oncology community. Practitioners in the radiation oncology community can play a critical role in promoting a value-oriented framework to approach radiation oncology treatment.

Temporal Trends and the Impact of Race, Insurance, and Socioeconomic Status in the Management of Localized Prostate Cancer.

BACKGROUND: Numerous management options exist for patients with prostate cancer; however, recent trends and their influencing factors are not well described. OBJECTIVE: To describe modern patterns of care and factors associated with management choice using the National Cancer Database. DESIGN, SETTING, AND PARTICIPANTS: Patients with localized prostate cancer diagnosed between 2004 and 2012 were included and grouped according to National Comprehensive Cancer Network guidelines into low, intermediate, or high risk. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Trend analyses and multivariate logistic regression was used to identify factors associated with management. RESULTS AND LIMITATIONS: There were 598 640 patients who met the study criteria; 36.3% were classified as low risk, 43.8% intermediate risk, and 20.0% high risk. Over the study period, among low-risk patients, observation increased from 9.2% to 21.3%, while radical prostatectomy (RP) increased from 29.5% to 51.1% (p<0.001 for both). In contrast, external beam radiotherapy decreased from 24.3% to 14.5%, while brachytherapy decreased from 31.7% to 11.1%. A similar pattern was seen for patients with intermediate-risk or high-risk disease. Among high-risk patients, RP increased from 25.1% to 43.4% replacing external beam radiotherapy as the dominant therapy. On multivariate analysis, racial minorities, the uninsured, and low-income patients were less likely to receive RP. Low-risk patients in similar subgroups were significantly more likely to be observed. Limitations include potential miscoding or misclassification of variables. CONCLUSIONS: Patterns of care in localized prostate cancer are changing rapidly. While use of observation is increasing in low-risk groups, the use of RP is increasing across all risk groups with a concomitant decline in use of radiotherapy. Socioeconomic factors appear to influence management choice. PATIENT SUMMARY: In this report we identify a recent significant increase in the use of radical prostatectomy for prostate cancer patients. Socioeconomic factors such as race, insurance type, and income may affect treatments offered to and received by patients.

Management and outcomes of clinical stage IIA/B seminoma: Results from the National Cancer Data Base 1998-2012.

PURPOSE/OBJECTIVE: Disease-specific survival for testicular seminoma approaches 100%, even for those with node-positive disease. We sought to describe modern practice patterns, survival outcomes, and factors associated with postoperative therapy for patients with clinical stage (CS) IIA/B disease. METHODS AND MATERIALS: Data on patients diagnosed with CS IIA/B seminoma from 1998 to 2012 were extracted from the National Cancer Data Base. Demographic, clinical, treatment, and payer characteristics were evaluated using multivariate regression to identify factors associated with receipt of chemotherapy or radiation therapy (RT) within 6 months of orchiectomy. Five-year Kaplan-Meier overall survival (OS) by CS and treatment was calculated. A Cox proportional hazards regression for 5-year OS was performed. RESULTS: A total of 1885 patients were included; 38.5% received chemotherapy and 61.5% received RT. On multivariate analysis, factors associated with receipt of postorchiectomy RT rather than chemotherapy included CS IIA (odds ratio [OR], 3.04; P < .01) and community treatment setting (OR, 1.81-2.76; P < .01). Reduced likelihood of receiving RT was associated with Medicaid insurance (OR, 0.50; P < .01), more recent year of diagnosis (continuous OR, 0.93; P < .01), and primary pathologic tumor 3/4 stage (OR, 0.47; P < .01). On multivariate Cox regression, decreased 5-year OS was associated with receipt of chemotherapy in CS IIA patients (hazard ratio, 13.33; P < .01) but not in CS IIB patients (hazard ratio, 1.39; P = .45). For CS IIA, 5-year OS was 99.4% for orchiectomy and RT versus 91.2% for orchiectomy and chemotherapy (log-rank P < .01). For CS IIB, 5-year OS was 96.1% for orchiectomy and RT versus 92.8% for orchiectomy and chemotherapy (log-rank P = .08). CONCLUSIONS: Consistent with national guideline recommendations, our analysis supports preferred status for RT in CS IIA. In addition, these data also support use of RT for CS IIB. CS, treatment year, primary pathologic tumor stage, insurance, and facility type were associated with type of postoperative therapy. Longer follow-up to account for potential late effects of treatment is needed.

Can We Advance Proton Therapy for Prostate? Considering Alternative Beam Angles and Relative Biological Effectiveness Variations When Comparing Against Intensity Modulated Radiation Therapy.

PURPOSE: For prostate treatments, robust evidence regarding the superiority of either intensity modulated radiation therapy (IMRT) or proton therapy is currently lacking. In this study we investigated the circumstances under which proton therapy should be expected to outperform IMRT, particularly the proton beam orientations and relative biological effectiveness (RBE) assumptions. METHODS AND MATERIALS: For 8 patients, 4 treatment planning strategies were considered: (A) IMRT; (B) passively scattered standard bilateral (SB) proton beams; (C) passively scattered anterior oblique (AO) proton beams, and (D) AO intensity modulated proton therapy (IMPT). For modalities (B)-(D) the dose and linear energy transfer (LET) distributions were simulated using the TOPAS Monte Carlo platform and RBE was calculated according to 3 different models. RESULTS: Assuming a fixed RBE of 1.1, our implementation of IMRT outperformed SB proton therapy across most normal tissue metrics. For the scattered AO proton plans, application of the variable RBE models resulted in substantial hotspots in rectal RBE weighted dose. For AO IMPT, it was typically not possible to find a plan that simultaneously met the tumor and rectal constraints for both fixed and variable RBE models. CONCLUSION: If either a fixed RBE of 1.1 or a variable RBE model could be validated in vivo, then it would always be possible to use AO IMPT to dose-boost the prostate and improve normal tissue sparing relative to IMRT. For a cohort without rectum spacer gels, this study (1) underlines the importance of resolving the question of proton RBE within the framework of an IMRT versus proton debate for the prostate and (2) highlights that without further LET/RBE model validation, great care must be taken if AO proton fields are to be considered for prostate treatments.

Cost implications and complications of overtreatment of low-risk prostate cancer in the United States.

BACKGROUND: Evidence-based consensus guidelines recommend only observation for men with low-risk prostate cancer and life expectancy less than 10 years. This report describes the incidence, drivers, cost, and morbidity of overtreatment of low-risk prostate cancer within the United States. METHODS: The SEER-Medicare Program was used to identify 11,744 men aged 66 years or older diagnosed with low-risk prostate cancer in 2004 through 2007. Overtreatment of prostate cancer was defined as definitive treatment of a patient with a life expectancy of less than 10 years. Expected survival was estimated using NCCN methodology. Costs were the amount paid by Medicare in years after minus year before diagnosis. Toxicities were relevant Medicare diagnoses/interventions. P values are 2-sided. RESULTS: Of 3001 men with low-risk prostate cancer and a life expectancy of less than 10 years, 2011 men (67%) were overtreated. On multivariable logistic regression, overtreated men were more likely to be married (odds ratio [OR], 1.29; 95% CI, 1.05-1.59; P=.02), reside in affluent regions (P<.001), and harbor more advanced disease at diagnosis (P<.001). Two-year toxicity was greater in overtreated patients (P<.001). Relative to active surveillance/watchful waiting/observation, the median additional cost per definitive treatment was $18,827 over 5 years; the cumulative annual cost attributable to overtreatment in the United States was $58.7 million. The ability to avoid treating the 80% of men with low-grade disease who will never die of prostate cancer would save $1.32 billion per year nationally. CONCLUSIONS: Overtreatment of low-risk prostate cancer is partially driven by sociodemographic factors and occurs frequently, with marked impact on patient quality of life and health-related costs.

Management trends in stage I testicular seminoma: Impact of race, insurance status, and treatment facility.

BACKGROUND: The management of stage I testicular seminoma is evolving rapidly. This study examined modern trends in the management of stage I testicular seminoma and the effects of sociodemographic factors on therapy choice. METHODS: Data from the National Cancer Data Base on 34,067 patients with stage I testicular seminoma who were treated between 1998 and 2011 were analyzed. Multivariate logistic regression models were used to assess factors associated with adjuvant management strategies. RESULTS: For patients with stage IA/B testicular seminoma, rates of observation after orchiectomy increased from 23.7% to 54.0%, the receipt of adjuvant chemotherapy increased from 1.5% to 16.0%, and the receipt of radiotherapy decreased from 70.8% to 28.8%. A similar pattern was seen in stage IS testicular seminoma, although these patients were more likely to receive adjuvant radiotherapy/chemotherapy (60.7% vs 44.8% for stage IA/B in 2011, P < .001). For patients with stage IA/B testicular seminoma, observation after orchiectomy was more common in racial minorities (odds ratio [OR] for blacks vs whites, 1.31, P < .001; OR for Hispanics vs whites, 1.39, P < .001) and in the uninsured (OR for uninsured vs privately insured, 1.33, P < .001) and less common at community centers (OR for community centers vs National Cancer Institute-designated cancer centers, 0.80, P = .044). In those with stage IA/B testicular seminoma who received adjuvant radiotherapy/chemotherapy, the receipt of chemotherapy was more common at academic centers and for patients with nonprivate insurance. CONCLUSIONS: Postorchiectomy observation in stage I testicular seminoma has increased significantly in recent years, as has the receipt of chemotherapy, whereas the receipt of radiotherapy has declined, particularly at academic centers. Race, insurance status, and facility type are strongly associated with the choice of adjuvant management.

Proton beam radiation therapy for prostate cancer-is the hype (and the cost) justified?

Although in use for over 40 years, proton beam therapy for prostate cancer has only recently come under public scrutiny, due to its increased cost compared to other forms of treatment. While the last decade has seen a rapid accumulation of evidence to suggest that proton beam therapy is both safe and effective in this disease site, a rigorous comparison to other radiotherapy techniques has not yet been completed. In this review, we provide an in-depth look at the evidence both supporting and questioning proton beam therapy's future role in the treatment of prostate cancer, with emphasis on its history, physical properties, comparative clinical and cost effectiveness, advances in its delivery and future promise.

Use of potentially curative therapies for muscle-invasive bladder cancer in the United States: results from the National Cancer Data Base.

BACKGROUND: Despite its lethal potential, many patients with muscle-invasive bladder cancer (MIBC) do not receive aggressive, potentially curative therapy consistent with established practice standards. OBJECTIVE: To characterize the treatments received by patients with MIBC and analyze their use according to sociodemographic, clinical, pathologic, and facility measures. DESIGN, SETTING, AND PARTICIPANTS: Using the National Cancer Data Base, we analyzed 28 691 patients with MIBC (stages II-IV) treated between 2004 and 2008, excluding those with cT4b tumors or distant metastases. Treatments included radical or partial cystectomy with or without chemotherapy (CT), chemoradiotherapy (CRT), radiation therapy (RT), or CT alone and observation following biopsy. Aggressive therapy (AT) was defined as radical or partial cystectomy or definitive RT/CRT (total dose ≥ 50 Gy). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: AT use and correlating variables were assessed by multivariable, generalized estimating equation models adjusted for facility clustering. RESULTS AND LIMITATIONS: According to the database, 52.5% of patients received AT; 44.9% were treated surgically, 7.6% received definitive CRT or RT, and 25.9% of patients received observation only. AT use decreased with advancing age (odds ratio [OR]: 0.34 for age 81-90 yr vs ≤ 50 yr; p<0.001). AT use was also lower in racial minorities (OR: 0.74 for black race; p<0.001), the uninsured (OR: 0.73; p<0.001), Medicaid-insured patients (OR: 0.81; p=0.01), and at low-volume centers (OR: 0.64 vs high-volume centers; p<0.001). Use of AT was higher with increasing tumor stage (OR: 2.23 for T3/T4a vs T2; p<0.001) and nonurothelial histology (OR: 1.25 and 1.43 for squamous and adenocarcinoma, respectively; p<0.001). Study limitations include retrospective design and lack of information about patient and provider motivations regarding therapy selection. CONCLUSIONS: AT for MIBC appears underused, especially in the elderly and in groups with poor socioeconomic status. These data point to a significant unmet need to inform policy makers, payers, and physicians regarding appropriate therapies for MIBC.

Prospective preference assessment of patients' willingness to participate in a randomized controlled trial of intensity-modulated radiotherapy versus proton therapy for localized prostate cancer.

PURPOSE: To investigate patients' willingness to participate (WTP) in a randomized controlled trial (RCT) comparing intensity-modulated radiotherapy (IMRT) with proton beam therapy (PBT) for prostate cancer (PCa). METHODS AND MATERIALS: We undertook a qualitative research study in which we prospectively enrolled patients with clinically localized PCa. We used purposive sampling to ensure a diverse sample based on age, race, travel distance, and physician. Patients participated in a semi-structured interview in which they reviewed a description of a hypothetical RCT, were asked open-ended and focused follow-up questions regarding their motivations for and concerns about enrollment, and completed a questionnaire assessing characteristics such as demographics and prior knowledge of IMRT or PBT. Patients' stated WTP was assessed using a 6-point Likert scale. RESULTS: Forty-six eligible patients (33 white, 13 black) were enrolled from the practices of eight physicians. We identified 21 factors that impacted patients' WTP, which largely centered on five major themes: altruism/desire to compare treatments, randomization, deference to physician opinion, financial incentives, and time demands/scheduling. Most patients (27 of 46, 59%) stated they would either "definitely" or "probably" participate. Seventeen percent (8 of 46) stated they would "definitely not" or "probably not" enroll, most of whom (6 of 8) preferred PBT before their physician visit. CONCLUSIONS: A substantial proportion of patients indicated high WTP in a RCT comparing IMRT and PBT for PCa.

Outcomes after intensity-modulated versus conformal radiotherapy in older men with nonmetastatic prostate cancer.

PURPOSE: There is little evidence comparing complications after intensity-modulated (IMRT) vs. three-dimensional conformal radiotherapy (CRT) for prostate cancer. The study objective was to test the hypothesis that IMRT, compared with CRT, is associated with a reduction in bowel, urinary, and erectile complications in elderly men with nonmetastatic prostate cancer. METHODS AND MATERIALS: We undertook an observational cohort study using registry and administrative claims data from the SEER-Medicare database. We identified men aged 65 years or older diagnosed with nonmetastatic prostate cancer in the United States between 2002 and 2004 who received IMRT (n = 5,845) or CRT (n = 6,753). The primary outcome was a composite measure of bowel complications. Secondary outcomes were composite measures of urinary and erectile complications. We also examined specific subsets of bowel (proctitis/hemorrhage) and urinary (cystitis/hematuria) events within the composite complication measures. RESULTS: IMRT was associated with reductions in composite bowel complications (24-month cumulative incidence 18.8% vs. 22.5%; hazard ratio [HR] 0.86; 95% confidence interval [CI], 0.79-0.93) and proctitis/hemorrhage (HR 0.78; 95% CI, 0.64-0.95). IMRT was not associated with rates of composite urinary complications (HR 0.93; 95% CI, 0.83-1.04) or cystitis/hematuria (HR 0.94; 95% CI, 0.83-1.07). The incidence of erectile complications involving invasive procedures was low and did not differ significantly between groups, although IMRT was associated with an increase in new diagnoses of impotence (HR 1.27, 95% CI, 1.14-1.42). CONCLUSION: IMRT is associated with a small reduction in composite bowel complications and proctitis/hemorrhage compared with CRT in elderly men with nonmetastatic prostate cancer.