Body composition and mortality in men receiving prostate radiotherapy: A pooled analysis of NRG/RTOG 9406 and NRG/RTOG 0126.

PURPOSE: To validate the association between body composition and mortality in men treated with radiation for localized prostate cancer (PCa). Secondarily, to integrate body composition as a factor to classify patients by risk of all-cause mortality. MATERIALS AND METHODS: Participants of NRG/Radiation Therapy Oncology Group (RTOG) 9406 and NRG/RTOG 0126 with archived computed tomography were included. Muscle mass and muscle density were estimated by measuring the area and attenuation of the psoas muscles on a single slice at L4-L5. Bone density was estimated by measuring the attenuation of the vertebral body at mid-L5. Survival analyses, including Cox proportional hazards models, assessed the relationship between body composition and mortality. Recursive partitioning analysis (RPA) was used to create a classification tree to classify participants by risk of death. RESULTS: Data from 2066 men were included in this study. In the final multivariable model, psoas area, comorbidity score, baseline prostate serum antigen, and age were significantly associated with survival. The RPA yielded a classification tree with four prognostic groups determined by age, comorbidity, and psoas area. Notably, the classification among older (≥70 years) men into prognostic groups was determined by psoas area. CONCLUSIONS: This study strongly supports that body composition is related to mortality in men with localized PCa. The inclusion of psoas area in the RPA classification tree suggests that body composition provides additive information to age and comorbidity status for mortality prediction, particularly among older men. More research is needed to determine the clinical impact of body composition on prognostic models in men with PCa.

Clinical Learning, Didactic Education, and Research Experiences of Radiation Oncology Resident Physicians in Canada.

Changes in the field of radiation oncology (RO) impacts residency training. Assessing trainee experiences is essential to inform curriculum development. We aim to explore gaps and strengths in current Canadian RO training, as we move towards competency-based medical education (CBME). An online survey was distributed to residents at all Canadian RO training programs. Surveys consisted of 66 open-ended, Likert-scale, matrix-style, and multiple-choice questions, and assessed clinical exposure, didactic teaching, professional relationships, and research experiences. Statistics were calculated from anonymized, aggregate responses. Out of 128 eligible residents, 53 responded (41% response rate). Of these, 57% were male, and 77% were Canadian medical graduates. Senior residents (PGY-4 to PGY-5) perceived insufficient exposure to lymphoma and ocular malignancies, brachytherapy for breast and esophagus malignancies, and stereotactic radiotherapy of the pancreas, prostate, and adrenal gland. Half (51%) had training on image-guided radiotherapy (IGRT) challenges, and 43% had a formal staff mentor. Most residents presented at least one research project at conferences (77%) and authored ≥ 1 publications (66%) during residency. Canadian RO residents are satisfied with their clinical training and educational experience in high-volume tumor sites and high-volume brachytherapy procedures. Areas identified for potential improvement are (1) low-volume tumor sites; (2) low-volume brachytherapy procedures; (3) low-volume stereotactic radiotherapy sites; (4) IGRT challenges; and (5) mentorship opportunities. These findings will inform future CBME curriculum revisions.

Motivations, Well-Being, and Career Aspirations of Radiation Oncology Resident Physicians in Canada.

Prior Pan-Canadian surveys of Radiation Oncology (RO) residents reveal a decrease in Canadian RO employment opportunities. Canadian RO resident levels increased from 130 in 2003, peaked at 209 in 2009, then decreased to 130 in 2017. Recognizing that RO has entered another period of transition, we re-examined resident motivations and perspectives on the job market and explored well-being and career aspirations among a contemporary cohort of Canadian RO residents. An online survey was distributed to residents at all Canadian RO training programs. Surveys consisted of 75 open-ended, Likert-scale, matrix-style, and multiple-choice questions. Student's t test compared subgroups, with statistical significance at p ≤ 0.05. Out of 128 eligible residents, 84 completed the survey (66% response rate) with representative sampling from each training year. Demographics reveal 53% male, and 85% Canadian registry-funded. Top training-related stressors were exam performance, job prospects, and physical/psychological demands of residency. Most intend to pursue fellowship post-residency (80%) and practice in Canada (88%). Few believe they can obtain staff positions treating preferred tumor sites (38%) or at preferred geographic locations (28%). Residents view job market being less competitive than 5 years ago (40%) and predict it will be less competitive in 5 years (60%). Canadian RO residents feel adequately trained, and most pursue post-residency fellowships. Current perceptions of the Canadian job market remain guarded, but appear more optimistic about the future. This update provides insights into current RO training and identifies areas that could be addressed by incoming competency-based medical education models for RO.

Informal caregiver quality of life in a palliative oncology population.

PURPOSE: Many patients with advanced cancer receive primary supports from informal caregivers (IC). As patient health deteriorates, IC assume increasing responsibility, often accompanied by distress. We investigated the quality of life (QOL) of IC of patients referred to a palliative radiotherapy (PRT) program. METHODS: IC accompanying patients to a dedicated PRT clinic completed a survey based on the validated Caregiver Quality of Life Index-Cancer (CQOLC). Demographics, burden, and engagement in support services were evaluated. Summary statistics were calculated, and parameters were assessed for association with CQOLC scores by a generalized linear model. RESULTS: Two hundred one surveys were analyzed representing 197 unique patients. The mean age was 68.3 years, with predominantly lung (25.0%) and prostate (19.3%) malignancies. 24.4% had been in hospital/long-term care within the previous 7 days. IC were 60.8% female, and 60.6% were the patient's spouse. 69.5% lived with the patient and 38.3% were additionally employed. IC spent a daily mean of 6.6 h (SD 7) assisting with instrumental (72.5%) and basic (37.5%) activities of daily living. Mean CQOLC score was 82.1/140 (SD 20). 63.8% of IC had previously accessed support service(s), most commonly home care (37.2%) and pharmacy (29.1%). 55.9% indicated interest in services not yet accessed. Multivariate analysis revealed additional employment, cohabitation, poor patient performance status, and interest in accessing more support services significantly correlated with higher IC burden. CONCLUSIONS: Employing the CQOLC to screen IC of patients referred to a PRT program permits early identification of vulnerable IC to facilitate linkage with appropriate supports.

Metformin for Prevention of Anthropometric and Metabolic Complications of Androgen Deprivation Therapy in Prostate Cancer Patients Receiving Radical Radiotherapy: A Phase II Randomized Controlled Trial.

BACKGROUND: Patients with prostate cancer undergoing treatment with radical radiation therapy (RT) plus androgen deprivation therapy (ADT) experience a constellation of deleterious metabolic and anthropometric changes related to hypogonadism that are associated with increased morbidity and mortality. We assessed the effect of metformin versus placebo to blunt the adverse effects of ADT on body weight, waist circumference, and other metabolic parameters. METHODS AND MATERIALS: This phase 2, multicenter, randomized controlled trial (RCT) randomized normoglycemic men with locally advanced prostate cancer receiving radical RT and ADT (18-36 months) in a 1:1 ratio to receive metformin 500 mg by mouth 3 times a day (for 30-36 months) versus identical placebo. RESULTS: From December 2015 to October 2019, 83 men were randomized with median follow-up of 23 months. Baseline mean body mass Index (BMI) of the cohort was 30.2 (range 22.2-52.5). Change in mean weight relative to baseline was lower among men who received metformin compared with placebo at 5 months (-1.80 kg, P = .038), but was not significant with longer follow-up (1 year: +0.16 kg, P = .874). Although participants on ADT had increases in waist circumference in both study arms, metformin did not significantly reduce these changes (1 year: +2.79 cm (placebo) versus +1.46 cm (metformin), P = .336). Low-density lipoprotein (LDL) cholesterol was lower in the metformin arm (-0.32 mmol/L) compared with the placebo arm (-0.03 mmol/L) at 5 months (P = .022), but these differences were not significant with longer follow-up (1 year: -0.17 mmol/L vs -0.19 mmol/L, P = .896). There were no differences in HbA1C, triglyceride, high-density lipoprotein (HDL) cholesterol, and total cholesterol by study arm. CONCLUSIONS: Men receiving radical RT and ADT gained weight and had increases in waist circumference over time that metformin did not significantly mitigate. Although this study did not observe any preventive effect of metformin on the anthropometric and metabolic complications of ADT, metformin continues to be studied in phase 3 RCTs in this patient population to assess its potential antineoplastic effects.

Conventional Versus Hypofractionated Radiation for High-Risk Prostate Cancer Patients (CHIRP): 24-Month Patient-Reported Outcomes of the Randomized Phase 2 CHIRP Trial.

PURPOSE: In this study, we report the 24-month patient-reported outcomes of the randomized phase 2 CHIRP trial that compared conventional and hypofractionated radiation therapy (RT) in the treatment of high-risk prostate cancer. METHODS AND MATERIALS: Men with high-risk localized prostate cancer were randomized to either conventional (78 Gy/39 fractions) or hypofractionated RT (68 Gy/25 fractions). All patients received pelvic nodal RT and adjuvant androgen deprivation therapy. Quality of life (QoL) data were collected through the expanded prostate cancer index composite and the short-form 12 (SF-12) health-related QoL questionnaire at baseline and at 3, 6, 12, 18, and 24 months posttreatment. We assessed change from baseline to account for differences in baseline comorbidities. Independent t test was used to identify differences between the 2 groups. RESULTS: Ninety-six participants were included in the QoL analysis, 49 in the hypofractionation arm and 47 in the standard fractionation arm. Urinary and sexual scores were similar between the 2 arms at all time points. Bowel bother scores exhibited a consistent trend favoring the standard arm from 3- to 18-months posttreatment and were statistically significant at 12 months (P = .016). SF-12 physical component scores showed a consistent trend favoring the hypofractionation arm from 6- to 18-months posttreatment and were statistically significant at 18 months (P = .017). At 24 months, there were no significant differences in QoL scores between the 2 groups. CONCLUSIONS: At 24 months post-RT, there were no major differences in patient-reported QoL between standard and hypofractionated RT. Early statistically significant differences in bowel bother and SF-12 physical component scores were no longer present at 24 months.

Adding Short-Term Androgen Deprivation Therapy to Radiation Therapy in Men With Localized Prostate Cancer: Long-Term Update of the NRG/RTOG 9408 Randomized Clinical Trial.

PURPOSE: For men with localized prostate cancer, NRG Oncology/Radiation Therapy Oncology Group (RTOG) 9408 demonstrated that adding short-term androgen deprivation therapy (ADT) to radiation therapy (RT) improved the primary endpoint of overall survival (OS) and improved disease-specific mortality (DSM), biochemical failure (BF), local progression, and freedom from distant metastases (DM). This study was performed to determine whether the short-term ADT continued to improve OS, DSM, BF, and freedom from DM with longer follow-up. METHODS AND MATERIALS: From 1994 to 2001, NRG/RTOG 9408 randomized 2028 men from 212 North American institutions with T1b-T2b, N0 prostate adenocarcinoma and prostate-specific antigen (PSA) ≤20ng/mL to RT alone or RT plus short-term ADT. Patients were stratified by PSA, tumor grade, and surgical versus clinical nodal staging. ADT was flutamide with either goserelin or leuprolide for 4 months. Prostate RT (66.6 Gy) was started after 2 months. OS was calculated at the date of death from any cause or at last follow-up. Secondary endpoints were DSM, BF, local progression, and DM. Acute and late toxic effects were assessed using RTOG toxicity scales. RESULTS: Median follow-up in surviving patients was 14.8 years (range, 0.16-21.98). The 10-year and 18-year OS was 56% and 23%, respectively, with RT alone versus 63% and 23% with combined therapy (HR 0.94; 95% confidence interval [CI], 0.85-1.05; P = .94). The hazards were not proportional (P = .003). Estimated restricted mean survival time at 18 years was 11.8 years (95% CI, 11.4-12.1) with combined therapy versus 11.3 years with RT alone (95% CI, 10.9-11.6; P = .05). The 10-year and 18-year DSM was 7% and 14%, respectively, with RT alone versus 3% and 8% with combined therapy (HR 0.56; 95% CI, 0.41-0.75; P < .01). DM and BF favored combined therapy at 18 years. Rates of late grade ≥3 hepatic, gastrointestinal, and genitourinary toxicity were ≤1%, 3%, and 8%, respectively, with combined therapy versus ≤1%, 2%, and 5% with RT alone. CONCLUSIONS: Further follow-up demonstrates that OS converges at approximately 15 years, by which point the administration of 4 months of ADT had conferred an estimated additional 6 months of life.

Gastrointestinal and genitourinary toxicity profiles of metformin versus placebo in men with prostate cancer receiving prostate radiotherapy: interim toxicity results of a double-blinded, multicenter, phase II randomized controlled trial.

Androgen deprivation therapy (ADT) used for prostate cancer (PCa) management is associated with metabolic and anthropometric toxicity. Metformin given concurrent to ADT is hypothesized to counteract these changes. This planned interim analysis reports the gastrointestinal and genitourinary toxicity profiles of PCa patients receiving ADT and prostate/pelvic radiotherapy plus metformin versus placebo as part of a phase 2 randomized controlled trial. Men with intermediate or high-risk PCa were randomized 1:1 to metformin versus placebo. Both groups were given ADT for 18-36 months with minimum 2-month neoadjuvant phase prior to radiotherapy. Acute gastrointestinal and genitourinary toxicities were quantified using CTCAE v4.0. Differences in ≥ grade 2 toxicities by treatment were assessed by chi-squared test. 83 patients were enrolled with 44 patients randomized to placebo and 39 randomized to metformin. There were no significant differences at any time point in ≥ grade 2 gastrointestinal toxicities or overall gastrointestinal toxicity. Overall ≥ grade 2 gastrointestinal toxicity was low prior to radiotherapy (7.9% (placebo) vs. 3.1% (metformin), p = 0.39) and at the end of radiotherapy (2.8% (placebo) vs 3.1% (metformin), p = 0.64). There were no differences in overall ≥ grade 2 genitourinary toxicity between treatment arms (19.0% (placebo) vs. 9.4% (metformin), p = 0.30). Metformin added to radiotherapy and ADT did not increase rates of ≥ grade 2 gastrointestinal or genitourinary toxicity and is generally safe and well-tolerated.

Clinical Outcomes of the CHIRP Trial: A Phase II Prospective Randomized Trial of Conventionally Fractionated Versus Moderately Hypofractionated Prostate and Pelvic Nodal Radiation Therapy in Patients With High-Risk Prostate Cancer.

PURPOSE: Hypofractionated radiation therapy (HFRT) may offer treatment advantages for patients with prostate cancer. However, HFRT may also increase the risk of gastrointestinal (GI) or genitourinary (GU) toxicity compared with conventionally fractionated radiation therapy (CFRT). Several large trials have found that HFRT is well tolerated in mixed risk population studies. Here, we report on a phase II, randomized controlled study conducted to evaluate these endpoints in exclusively high-risk patients with prostate cancer treated with prostate and pelvic nodal radiation. METHODS AND MATERIALS: After giving informed consent, patients with high-risk prostate cancer were randomly assigned to prostate plus pelvic nodal radiation therapy with either HFRT (68 Gy in 25 fractions) or CFRT (78 Gy in 39 fractions) and 18 months of androgen suppression therapy. Toxicity was scored using the Common Terminology Criteria for Adverse Events (version 4.0). Biochemical failure was determined by the Phoenix definition. Patients were analyzed on an intention-to-treat basis. RESULTS: From 2012 to 2018, 111 patients with high-risk prostate cancer were enrolled and 109 patients were treated. The cumulative incidence of grade 2 or higher acute GI toxicity was not significantly different between the arms (HFRT 18.9% vs CFRT 21.8%; P = .812). Similarly, acute GU (HFRT 30.2% vs CFRT 30.9%; P = 1.00), late GI (HFRT 16.0% vs CFRT 10.0%; P = .554), and late GU (HFRT 16.0% vs CFRT 6.0%; P = .200) were not significantly different between the arms. Median follow-up was 38.0 months (4.8-77.8 months). The 3-year biochemical recurrence-free survival was not significantly different between the 2 arms (97.3% for HFRT vs 91.0% for CFRT; P = .606). The 3-year overall survival was 94.8% in the HFRT arm and 100.0% in the CFRT arm (P = .116). CONCLUSIONS: HFRT and CFRT using intensity modulated radiation therapy were both well tolerated for patients with high-risk prostate cancer and resulted in similar 3-year biochemical recurrence-free survival and overall survival.

Identification of a new microRNA expression profile as a potential cancer screening tool.

PURPOSE: Small non-coding microRNAs (miRNAs) are key components of cancer development and are considered as potential biomarkers for cancer diagnosis and treatment monitoring. This study investigated miRNA expression profiles of human cancer cells in order to develop a screening method for lung cancer. METHODS: A series of lung cancer related miRNAs (miR-21, miR-145, miR-155, miR-205, miR-210, miR-92, miR-17-5p, miR-143, miR-182, miR-372, let-7a) were selected as candidates for miRNA expression profiles of human lung cancer cell lines (A549, SK-mes-1). MicroRNA u6 was the endogenous control. Cancer cell lines for positive controls; breast MCF-7, prostate Du-145, and glioblastoma U118. The negative control was normal lung fibroblast cell line MRC-5. RT-PCR was performed on StepOnePlus (Applied Biosystem, USA). MiRNA expressions of malignant cells were compared with normal fibroblast cells as well as endogenous control (u6) using the thermal cycle at threshold. Assessment of miRNA expression profiles were then performed using agglomerative hierarchical cluster analysis software (SPSS13, USA). RESULTS: We demonstrated that miR-21, miR-182 and let7-5a were over-expressed, and miR-145 and miR-155 were under-expressed in all cancer cell lines. Combined with the cluster analysis we were able to clearly distinguish cell lines for normal fibroblasts, breast cancer, prostate cancer, glioblastoma, and lung cancer. CONCLUSION: There is potential utility of screening for lung cancer with miRNA expression profiles. Future work will focus on the sensitivity of such miRNA expression profiles in screening sputum for lung cancer, which can be performed in real time.

Should Stereotactic Radiosurgery Be Considered for Salvage of Intracranial Recurrence after Prophylactic Cranial Irradiation or Whole Brain Radiotherapy in Small Cell Lung Cancer? A Population-Based Analysis and Literature Review.

BACKGROUND: Prophylactic cranial irradiation (PCI) improves survival and prevents intracranial recurrence (IR) in limited stage (LS) and extensive stage (ES) small cell lung cancer (SCLC). However, despite PCI, IR affects 12%-45%, and limited data exist regarding salvage brain reirradiation (ReRT). We performed a population-based review of IR in SCLC. METHODS: Demographic, treatment, and outcome data of consecutive patients (N = 371) with SCLC assessed at a tertiary cancer centre (01/2013-12/2015) were abstracted, and summary statistics calculated. Kaplan-Meier estimates and univariate and multivariate analysis (MVA) via the Cox proportional hazard model were performed. RESULTS: Median age was 66.1 years, and 59.8% were Eastern Cooperative Oncology Group (ECOG) performance status 0-2. Median survival was 24 months (95% CI 18.3-29.7 months) for LS (N = 103) and 7 months (95% CI 6.1-7.9 months) for ES (N = 268). 72 of 103 patients with LS and 97 of 214 of those with ES received PCI. 54 of 268 ES presented with brain metastases (BM) of whom 46 of 54 received whole brain RT (WBRT). 18.9% (32/169) recurred post-PCI (13 LS; 19 ES) and 30.4% (14/46) recurred after WBRT. Of those who recurred/progressed after cranial RT, 56.5% (26/46) had <5 BM, 39.1% had no extracranial disease, and 50% were ECOG 0-2. In retrospect, 17 of 46 would have been candidates for salvage stereotactic radiosurgery: 13 post-PCI and 4 post-WBRT. CONCLUSIONS: This cohort challenges commonly held beliefs that IR is always diffuse, associated with clinical deterioration, and synchronous with systemic failure. Approximately 1 in 3 SCLC patients with IR after PCI or WBRT appear clinically appropriate for salvage stereotactic radiosurgery.

Enhanced radiation sensitivity in prostate cancer by gold-nanoparticles.

PURPOSE: Nanotechnology is an emerging field with significant translational potential in medicine. In this study, we applied gold nanoparticles (GNP) to enhance radiation sensitivity and growth inhibition in radiation-resistant human prostate cancer cells. METHODS: Gold nanoparticles (GNPs) were synthesized using HAuCl4 as the gold particle source and NaBH4 as the reductant. Either thio-glucose or sodium citrate was then added to the solution separately to bind the GNPs to form thio-glucose-capped gold nanoparticles (Glu-GNP) and neutral gold nanoparticles (TGS-GNPs). Human prostate carcinoma DU-145 cells were exposed to vehicle, irradiation, 15nM TGS-GNPs, or 15nM Glu-GNPs, or GNPs plus irradiation. The uptake assays of GNP were performed using hemocytometer to count cells and the mass spectrometry was applied to calculate gold mass. The cytotoxicity induced by GNPs, irradiation, or GNPs plus irradiation was measured using a standard colorimetric MTT assay. RESULTS: Exposure to Glu-GNPs resulted in a three times increase of nanoparticle uptake compared to that of TGS-GNPs in each target cell (p < 0.005). Cytoplasmic intracellular uptake of both TGS-GNPs and Glu-GNPs resulted in a growth inhibition by 30.57% and 45.97% respectively, comparing to 15.88% induced by irradiation alone, in prostate cancer cells after exposure to the irradiation. Glu-GNPs showed a greater enhancement, 1.5 to 2 fold increases within 72 hours, on irradiation cytotoxicity compared to TGS-GNPs. Tumour killing, however, did not appear to correlate linearly with nanoparticle uptake concentrations. CONCLUSION: These results showed that functional glucose-bound gold nanoparticles enhanced radiation sensitivity and toxicity in prostate cancer cells. In vivo studies will be followed to verify our research findings.

Initial clinical assessment of "center-specific" automated treatment plans for low-dose-rate prostate brachytherapy.

PURPOSE: To report results of an initial pilot study assessing iodine-125 prostate implant treatment plans created automatically by a new seed-placement method. METHODS AND MATERIALS: A novel mixed-integer linear programming method incorporating spatial constraints on seed locations in addition to standard dose-volume constraints was used to place seeds. The approach, described in detail elsewhere, was used to create treatment plans fully automatically on a retrospective basis for 20 patients having a wide range of prostate sizes and shapes. Corresponding manual plans used for patient treatment at a single institution were combined with the automated plans, and all 40 plans were anonymized, randomized, and independently evaluated by five clinicians using a common scoring tool. Numerical and clinical features of the plans were extracted for comparison purposes. RESULTS: A full 51% of the automated plans were deemed clinically acceptable without any modification by the five practitioners collectively versus 90% of the manual plans. Automated plan seed distributions were for the most part not substantially different from those for the manual plans. Two observed shortcomings of the automated plans were seed strands not intersecting the prostate and strands extending into the bladder. Both are amenable to remediation by adjusting existing spatial constraints. CONCLUSIONS: After spatial and dose-volume constraints are set, the mixed-integer linear programming method is capable of creating prostate implant treatment plans fully automatically, with clinical acceptability sufficient to warrant further investigation. These plans, intended to be reviewed and refined as necessary by an expert planner, have the potential to both save planner time and enhance treatment plan consistency.

Evaluating performance of a user-trained MR lung tumor autocontouring algorithm in the context of intra- and interobserver variations.

PURPOSE: Real-time tracking of lung tumors using magnetic resonance imaging (MRI) has been proposed as a potential strategy to mitigate the ill-effects of breathing motion in radiation therapy. Several autocontouring methods have been evaluated against a "gold standard" of a single human expert user. However, contours drawn by experts have inherent intra- and interobserver variations. In this study, we aim to evaluate our user-trained autocontouring algorithm with manually drawn contours from multiple expert users, and to contextualize the accuracy of these autocontours within intra- and interobserver variations. METHODS: Six nonsmall cell lung cancer patients were recruited, with institutional ethics approval. Patients were imaged with a clinical 3 T Philips MR scanner using a dynamic 2D balanced SSFP sequence under free breathing. Three radiation oncology experts, each in two separate sessions, contoured 130 dynamic images for each patient. For autocontouring, the first 30 images were used for algorithm training, and the remaining 100 images were autocontoured and evaluated. Autocontours were compared against manual contours in terms of Dice's coefficient (DC) and Hausdorff distances (dH ). Intra- and interobserver variations of the manual contours were also evaluated. RESULTS: When compared with the manual contours of the expert user who trained it, the algorithm generates autocontours whose evaluation metrics (same session: DC = 0.90(0.03), dH  = 3.8(1.6) mm; different session DC = 0.88(0.04), dH  = 4.3(1.5) mm) are similar to or better than intraobserver variations (DC = 0.88(0.04), and dH  = 4.3(1.7) mm) between two sessions. The algorithm's autocontours are also compared to the manual contours from different expert users with evaluation metrics (DC = 0.87(0.04), dH  = 4.8(1.7) mm) similar to interobserver variations (DC = 0.87(0.04), dH  = 4.7(1.6) mm). CONCLUSIONS: Our autocontouring algorithm delineates tumor contours (<20 ms per contour), in dynamic MRI of lung, that are comparable to multiple human experts (several seconds per contour), but at a much faster speed. At the same time, the agreement between autocontours and manual contours is comparable to the intra- and interobserver variations. This algorithm may be a key component of the real time tumor tracking workflow for our hybrid Linac-MR device in the future.

Unexpected Seed Migration in Prostate Brachytherapy Implants Coincident with Change in Seed Stranding Product.

PURPOSE: This study was undertaken to determine if significant seed migration occurred when our institution changed seed products by comparing patterns of seed migration in implants containing different stranding material. METHODS AND MATERIALS: Day 0 and Day 30 CT scans were registered by the contoured prostate center of mass. An implant reconstruction program identified seeds on CT according to the pre-plan, enabling one-to-one correspondence between Day 0 and Day 30 seeds. Significant seed migration was defined by review of seeds that migrated > 2 cm outside the prostate or appearance in unexpected locations.   Results: Twenty-five (149, 16.8%) new strands displayed movement > 2 cm between Day 0 and Day 30 compared with just 2/118 (1.7%) of the standard strands. Six out of 26 (23%) patients with new strands displayed significant migration compared with 2/13 (14%) of patients with standard strands. In the six patients with new strands and significant migration, a mean of four strands (17%, range: 2-8 per patient) migrated significantly with 65% due to whole strand migration, 25% due to strand breakage, and 10% strand clumping. In the control group, only two strands (2%) migrated significantly, both due to strand breakage. Despite the greater seed movement with the new strands, Day 0 and Day 30 dosimetry was acceptable. CONCLUSION: In this short report, we identified that a change to a new strand type was associated with unexpected significant seed movement compared to our typical strands. Since seed movement can arise from unexpected causes, it is important to maintain quality assurance practices when a change in technique or infrastructure is instituted.

Quantifying 125I placement accuracy in prostate brachytherapy using postimplant transrectal ultrasound images.

PURPOSE: The quality of a prostate brachytherapy implant depends on the accurate placement of sources. This study quantifies the misplacement of 125I sources from the intended location using intraoperative ultrasound images. METHODS AND MATERIALS: 125I sources were manually identified in the postimplant ultrasound images and compared to the preoperative plan. Due to the subjective nature of the identifying sources, only sources identified with high confidence were included in the analysis. Misplacements from the original intended coordinate were measured along the X, Y, and Z axes and were stratified between overall misplacements and regions of the prostate gland. RESULTS: A total of 1619 125I sources using 357 strands were implanted in 15 patients' prostate glands, with 1197 (74%) confidently identified for misplacement analysis. The overall mean displacement was 0.49 cm and in the X, Y, and Z direction was 0.13, 0.15, and 0.38 cm, respectively. Greater source misplacement occurred in the anterior part of the prostate gland than the posterior part of the prostate gland by a factor 1.33 (p < 0.0001). Comparing sources in the lateral vs. medial regions of the prostate, no statistically significant differences on source misplacement were observed. Comparing misplacement in the base vs. midgland vs. apex identified the greatest difference between the base and midgland by a factor of 1.29 (p < 0.0001). CONCLUSIONS: This study has identified significant misplacement of 125I sources from their intended locations with the greatest error misplacement occurring in the Z direction. Source misplacement tends to occur more commonly in the anterior gland and in the base of the prostate.

Late Toxicity and Outcomes in High-risk Prostate Cancer Patients Treated With Hypofractionated IMRT and Long-term Androgen Suppression Treatment.

OBJECTIVE: To assess late toxicity and outcomes in high-risk prostate cancer patients treated with hypofractionated radiation treatment with androgen suppression therapy. METHODS: Sixty high-risk prostate cancer patients were enrolled. IMRT prescription was 68 Gy/25 fractions (2.7 Gy/fraction) to the prostate and proximal seminal vesicles (SV). The pelvic lymph nodes (PLN) and distal SV concurrently received 45 Gy/25 fractions (1.8 Gy/fraction). The patients were treated with helical TomoTherapy-based IMRT and underwent daily megavoltage CT image-guided verification before each treatment. RTOG Toxicity scores were recorded for a 5-year period. RESULTS: Sixty patients completed RT with median follow-up of 63 months (range, 7 to 80 mo).At 5 years follow-up timepoint: Grade (G)2 and G3 late genitourinary toxicity was experienced in 7 (17.0%) and 1 (2.44%), respectively; gastrointestinal G2 as highest toxicity recorded in only 1 (2.44%) patient. There was no G3 gastrointestinal toxicity recorded at this timepoint.With 63-month median follow-up (mean of 65.41±1.72 mo), the 5-year overall survival was 86.67%; 5 years freedom from biochemical failure was 91.67% and freedom from clinical failure was 96.67%. CONCLUSIONS: Dose escalation and hypofractionated radiation treatment with IMRT treating the prostate and proximal SV concurrently with the pelvic lymph nodes and distal SV and long-term androgen suppression therapy is well tolerated with respect to acute and late toxicity with 5-year actuarial overall survival 86.67%, freedom from biochemical failure 91.38%, and freedom from clinical failure 96.67%. Longer follow-up will provide more information on 10-year survival outcomes.

Dose-escalated Hypofractionated Intensity-modulated Radiation Therapy With Concurrent Chemotherapy for Inoperable or Unresectable Non-Small Cell Lung Cancer.

PURPOSE: The local control of inoperable non-small cell lung cancer (NSCLC) using standard radiotherapy (RT) doses is inadequate. Dose escalation is a potential strategy to improve the local control for patients with NSCLC; however, the optimal dose required for local control in this setting is unknown. METHODS AND MATERIALS: Patients with unresectable or inoperable stage II/III NSCLC with ECOG≤1 received 48 Gy in 20 daily fractions using intensity-modulated radiotherapy, followed by 1 of 3 boost dose levels: 16.8 Gy/7 (cumulative 2 Gy equivalent dose [EQD2]≅76 Gy/38), 20.0 Gy/7 (EQD2≅84 Gy/42), and 22.7 Gy/7 (EQD2≅92 Gy/46). Two cycles of cisplatin/etoposide chemotherapy were given concurrent with RT. The maximum tolerated dose was defined as the dose at which ≥30% experienced dose-limiting toxicity (any NCIC Common Terminology for Adverse Events V3.0 grade 3 or higher acute toxicity). RESULTS: Twelve patients completed treatment with a median follow-up of 22 months (range, 7 to 48). The median age was 72 (range, 54 to 80) and 50% of patients had adenocarcinoma. Five, 3, and 4 patients were treated on dose levels 1, 2, and 3, respectively. No dose-limiting toxicity was observed. One-year local progression-free survival and overall survival estimates were 81% and 58%, respectively. CONCLUSIONS: Hypofractionated intensity-modulated radiotherapy was well tolerated and provided meaningful local control for patients with locally advanced inoperable NSCLC. The maximum tolerated dose of RT in this setting lies beyond an EQD2 of 92 Gy/46 and further dose escalation in this setting is warranted.

Phase I study of hypofractionated dose-escalated thoracic radiotherapy for limited-stage small-cell lung cancer.

PURPOSE: To determine the maximal tolerated dose of hypofractionated thoracic radiotherapy with concurrent chemotherapy for limited-stage small-cell lung cancer patients. METHODS AND MATERIALS: Three radiotherapy regimens were used. Radiotherapy was given in two phases: patients initially received 20 Gy in 10 fractions to gross tumor plus uninvolved mediastinal nodes, followed by a boost to gross disease of 30, 38, or 42 Gy in 15 fractions. Radiotherapy was planned with conformal techniques. All patients received four cycles of cisplatin (25 mg/m2) and etoposide (100 mg/m2) chemotherapy. Radiotherapy commenced with Day 1 of Cycle 2 of chemotherapy. All complete/near-complete responders were offered prophylactic cranial irradiation. The maximal tolerated dose of radiotherapy was based on the dose that caused unacceptably high rates of radiotherapy-related toxicity. RESULTS: Thirteen patients were accrued. All patients who commenced radiotherapy received all prescribed chemo- and radiotherapy. There were no treatment-related deaths. There was one Grade 3 acute nonhematologic toxicity in the 50-Gy group. Of the 6 patients given 58 Gy, 3 experienced acute Grade 3 esophagitis. With a median follow-up of 7 months, median overall survival was 9.5 months. CONCLUSIONS: The maximal tolerated dose of thoracic radiotherapy with concurrent chemotherapy on this trial was 50 Gy in 25 daily fractions.

2003 survey of Canadian radiation oncology residents.

PURPOSE: Radiation oncology's popularity as a career in Canada has surged in the past 5 years. Consequently, resident numbers in Canadian radiation oncology residencies are at all-time highs. This study aimed to survey Canadian radiation oncology residents about their opinions of their specialty and training experiences. METHODS AND MATERIALS: Residents of Canadian radiation oncology residencies that enroll trainees through the Canadian Resident Matching Service were identified from a national database. Residents were mailed an anonymous survey. RESULTS: Eight of 101 (7.9%) potential respondents were foreign funded. Fifty-two of 101 (51.5%) residents responded. A strong record of graduating its residents was the most important factor residents considered when choosing programs. Satisfaction with their program was expressed by 92.3% of respondents, and 94.3% expressed satisfaction with their specialty. Respondents planning to practice in Canada totaled 80.8%, and 76.9% plan to have academic careers. Respondents identified job availability and receiving adequate teaching from preceptors during residency as their most important concerns. CONCLUSIONS: Though most respondents are satisfied with their programs and specialty, job availability and adequate teaching are concerns. In the future, limited time and resources and the continued popularity of radiation oncology as a career will magnify the challenge of training competent radiation oncologists in Canada.