Apparent diffusion coefficient values predict response to brachytherapy in bulky cervical cancer.

BACKGROUND: Diffusion-weighted magnetic resonance imaging (DWI) provides a measurement of tumor cellularity. We evaluated the potential of apparent diffusion coefficient (ADC) values obtained from post-external beam radiation therapy (EBRT) DWI and prior to brachytherapy (BT) to predict for complete metabolic response (CMR) in bulky cervical cancer. METHODS: Clinical and DWI (b value = 500 s/mm2) data were obtained from patients undergoing interstitial BT with high-risk clinical target volumes (HR-CTVs) > 30 cc. Volumes were contoured on co-registered T2 weighted images and 90th percentile ADC values were calculated. Patients were stratified by CMR (defined by PET-CT at three months post-BT). Relation of CMR with 90th percentile ADC values and other clinical factors (International Federation of Gynecology and Obstetrics (FIGO) stage, histology, tumor and HR-CTV size, pre-treatment hemoglobin, and age) was assessed both in univariate and multivariate logistic regression analyses. Youden's J statistic was used to identify a threshold value. RESULTS: Among 45 patients, twenty-eight (62%) achieved a CMR. On univariate analysis for CMR, only 90th percentile ADC value was significant (p = 0.029) while other imaging and clinical factors were not. Borderline significant factors were HR-CTV size (p = 0.054) and number of chemotherapy cycles (p = 0.078). On multivariate analysis 90th percentile ADC (p < 0.0001) and HR-CTV size (p < 0.003) were highly significant. Patients with 90th percentile ADC values above 2.10 × 10- 3 mm2/s were 5.33 (95% CI, 1.35-24.4) times more likely to achieve CMR. CONCLUSIONS: Clinical DWI may serve to risk-stratify patients undergoing interstitial BT for bulky cervical cancer.

A pooled long-term follow-up after radiotherapy for prostate cancer with and without a rectal hydrogel spacer: impact of hydrogel on decline in sexual quality of life.

Purpose: The purpose of this study was to analyze the impact of prostate rectal spacers on sexual quality of life (QOL) following external beam radiation therapy (RT). Methods and materials: Patient- reported QOL was evaluated using the Expanded Prostate Cancer Index Composite (EPIC). Patients were pooled from two sources: a randomized controlled trial and a non-randomized cohort of patients from a single institution. Both cohorts used the same spacing product and QOL instrument. Analysis was limited to those with good baseline pre-treatment sexual QOL (EPIC >/= 60). Differences in QOL summary score and individual items were assessed compared with baseline and between treatment arms. Results: A total of 128 men had good baseline sexual function and were evaluated (64% with spacer and 36% without) with QOL data available for median 33 months (range: 2.5-69.4 months). Men without spacer were more likely to have declines in sexual function (p < 0.0001), bother (p = 0.0002), and sexual summary score (p < 0.0001). A minimally important difference of 10 points (1xMID) and 20 point (2xMID) was more likely without rectal spacer [10 points: odds ratio 3.53, (95% confidence interval 1.11-11.2), p = 0.032; 20 points: odds ratio 3.29, (95% confidence interval 1.16-9.33), p = 0.025]. Seven of 13 QOL items were statistically superior with hydrogel (six of nine functional and one of four bother), while no items were statistically superior for control. At baseline, more men treated with hydrogel had erections sufficient for intercourse; however, when analyzed only by the men with best baseline erectile potential and excluding those with worse function, the benefit of rectal spacing was maintained with a higher likelihood of preservation of erections sufficient for intercourse in those treated with hydrogel. Conclusion: In this pooled analysis of QOL after prostate RT, the utilization of a hydrogel spacer was associated with better sexual QOL, less men with measurable declines in sexual QOL, and higher rates of adequate erectile function.

Predictors of follow-up non-compliance after definitive radiotherapy for locally advanced cervical cancer at a community cancer center.

Introduction: Non-compliance to post-treatment cancer surveillance can lead to late detection of recurrence. This study aims to identify patients at high risk for loss of follow-up after radiotherapy for locally advanced cervical cancer. Methods: Consecutive patients with locally advanced cervical cancer treated with definitive chemoradiotherapy (2013-2020) at a community cancer center were retrospectively reviewed. The main outcome was overall follow-up compliance rate over time. Additionally, specialist-specific follow-up times, reasons for discontinuation and predictors of loss of follow-up events were evaluated. Results: The median age of the 154 patients included was 46.5 years (range: 26-84). The 6-month, 1-, 3-, and 5-year overall loss of follow-up rates were: 5.3%, 15.3%, 33.6%, and 48.2%, respectively. After a median overall follow-up time of 21.0 months, the median specialist-specific surveillance times were 17 months and 6 months with gynecologic and radiation oncologists, respectively (p < 0.01). Overall, the most common reasons for loss of follow-up were financial (21.7%) and relocation to another city (28.3%). By specialty, the most common reasons were relocation of care (56.5%, gynecologic oncologist) and disease progression (31.3%, radiation oncologist). In the multivariable analysis, older age (continuous, OR: 0.96; p < 0.01) and Hispanic ethnicity (OR: 0.39; p < 0.01) were protective against loss of follow-up, while increased number of gestations (continuous, OR: 1.23, p = 0.01) and living farther from the cancer center (continuous, OR: 1.002; p = 0.03) increased the chance of loss of follow-up. Conclusion: Younger, non-Hispanic, multiparous women that live far from the community cancer center have an increased chance of follow-up discontinuity, which are attributed to financial reasons in more than 20% of the cases.

Patient reported outcomes for quality of life (QOL) by Expanded Prostate Cancer Index (EPIC) on average 15 years post treatment.

Objective/purpose: Previously patient reported quality of life (QOL) was reported in men with prostate cancer a mean 2 and 6 years post treatment with open radical prostatectomy (RP), 3D conformal radiation therapy (3D CRT), or 125I low dose rate (LDR) brachytherapy (BT). Herein we update the results 15 years post-treatment QOL. Materials/methods: The Expanded Prostate Cancer Index (EPIC) domains were scored with differences evaluated at a median 15.8 years follow up based upon mean EPIC summary domains by ANOVA with pairwise post-hoc comparisons adjusted for age. Patient differences of current survey from first cross-section are reported as median change in summary score for each treatment group at median of 2.2 and 6.0, and 15.8 years. Results: Among men still alive response rate was 52% in BT, 60% in 3D CRT, and 62% in RP resulting in 30, 41, and 330 QOL questionnaires to evaluate for each corresponding modality at median follow up of 15.8 years. Men were a mean 75.3, 83.6, and 79.3 years of age after RP, 3DCRT, and BT, respectively.At a median of 15.8 years, there were largely persistent differences in EPIC domains without substantial evolution in QoL from middle time points. Persistent worsening in urinary irritative and bowel domain with 3DRT or BT compared to RP. Trend towards worse urinary incontinence with RP were noted without statistical differences within radiotherapy options. Conclusion: As the EPIC patient reported outcomes with the longest follow-up, these data uniquely reveal temporal trends from 2 to 15 years post treatment. However, the treatment modalities of open RP, 3D CRT without image guidance or intensity modulation, and BT without peripheral loading or MRI guidance may not reflect modern techniques.

Co-Inhibition of Androgen Receptor and PARP as a Novel Treatment Paradigm in Prostate Cancer-Where Are We Now?

Metastatic prostate cancer remains lethal with a 5-year survival rate of about 30%, indicating the need for better treatment options. Novel antiandrogens (NAA)-enzalutamide and abiraterone-have been the mainstay of treatment for advanced disease since 2011. In patients who progress on the first NAA, responses to the second NAA are infrequent (25-30%) and short-lasting (median PFS ~3 months). With the growing adoption of NAA therapy in pre-metastatic castration-resistant settings, finding better treatment options for first-line mCRPC has become an urgent clinical need. The regulatory approval of two PARP inhibitors in 2020-rucaparib and olaparib-has provided the first targeted therapy option for patients harboring defects in selected DNA damage response and repair (DDR) pathway genes. However, a growing body of preclinical and clinical data shows that co-inhibition of AR and PARP induces synthetic lethality and could be a promising therapy for patients without any DDR alterations. In this review article, we will investigate the limitations of NAA monotherapy, the mechanistic rationale for synthetic lethality induced by co-inhibition of AR and PARP, the clinical data that have led to the global development of a number of these AR and PARP combination therapies, and how this may impact patient care in the next 2-10 years.

Long-term follow-up after radiotherapy for prostate cancer with and without rectal hydrogel spacer: a pooled prospective evaluation of bowel-associated quality of life.

OBJECTIVE: To evaluate the long-term bowel-associated quality of life (QOL) in men after radiotherapy (RT) for prostate cancer with and without the use of rectal hydrogel spacer. PATIENTS AND METHODS: The patients' QOL was examined using the Expanded Prostate Cancer Index Composite (EPIC) and mean changes from baseline in EPIC domains were evaluated. A total of 215 patients from a randomised multi-institutional trial of RT, with or without hydrogel spacer, with a QOL endpoint were pooled with 165 non-randomised patients from a single institution with prospective QOL collection in patients with or without hydrogel spacer. The proportions of men with minimally important differences (MIDs) relative to pre-treatment baseline in the bowel domain were tested using repeated measure logistic models with a pre-specified threshold for clinically significant declines (≥5 equivalent to MIDx1 and ≥10 equivalent to MIDx2). RESULTS: A total of 380 men were evaluated (64% with spacer and 36% without) with QOL data being available for 199 men with >24 months of follow-up [median (range) 39.5 (31-71.4) months]. Treatment with spacer was associated with less decline in average long-term bowel QOL (89.4 for control and 94.7 for spacer) with differences at >24 months meeting the threshold of a MID difference between cohorts (bowel score difference from baseline: control = -5.1, spacer = 0.3, difference = -5.4; P < 0.001). When evaluated over time men without spacer were more likely to have MIDx1 (5 points) declines in bowel QOL (P = 0.01). At long-term follow-up MIDx1 was 36% without spacer vs 14% with spacer (P <0.001; odds ratio [OR] 3.5, 95% CI 1.7-6.9) while MIDx2 was seen in 19% vs 6% (P = 0.008; OR 3.6, 95% CI 1.4-9.1). The use of spacer was associated with less urgency with bowel movements (P = 0.002) and fewer loose stools (P = 0.009), as well as less bother with urgency (P = 0.007) and frequency of bowel movements (P = 0.009). CONCLUSIONS: In this pooled analysis of QOL after prostate RT with up to 5 years of follow-up, use of a rectal spacer was associated with preservation of bowel QOL. This QOL benefit was preserved with long-term follow-up.

Who Benefits From a Prostate Rectal Spacer? Secondary Analysis of a Phase III Trial.

PURPOSE: Previously a phase III trial of a hydrogel rectal spacer during prostate radiation therapy found decreased toxicity and a clinically significant improvement in bowel quality of life (QOL) at 3 years by the Expanded Prostate Cancer Index. We performed a secondary analysis to identify men less likely to benefit. METHODS AND MATERIALS: Clinical and dosimetric data for the 222 patients enrolled on the SpaceOAR phase III trial were analyzed. The volume of rectum treated to 70 Gy (V70) and the quantitative analysis of normal tissue effects in the clinic (QUANTEC) rectal dose goals were used as surrogates for clinical benefit and plan quality. Mean bowel QOL was assessed at 15 and 36 months posttreatment and the likelihood of 1× (5 points) or 2× (10 points) minimally important difference changes were assessed. RESULTS: Rectal V70 was correlated with physician scored toxicity (P = .033) and was used as a surrogate for plan quality. There was no correlation between prostate volume and rectal V70 (r = 0.077). Rectal V70 pre- and post-hydrogel was 13% and 3% for the smallest prostates (<40 mL) and 12% and 2% for the largest (>80 mL). The relative reduction in rectal V70 of 78% did not vary by prespacer V70, but the absolute reduction was greater for a higher V70. All spacer plans met the 5 QUANTEC rectal dose constraints, although 92% of control plans met all constraints. At 3 years, those not meeting all QUANTEC goals had a 15.0-point (standard deviation 15.1) decline, control patients meeting QUANTEC goals had a 4.0-point (9.5) decline, and spacer had >0.5 (7.6; P < .01). Previous surgery was not correlated with QOL (P = .8). Across prognostic groups, including age, body mass index, previous surgery, target volume, or quality of radiation plans, there was no statistically significant heterogeneity in the relative benefit of spacer in decreasing the risk of 1× or 2× the minimally important difference declines. CONCLUSIONS: There was little heterogeneity in the likelihood of spacer reducing the risk of declines in bowel QOL across clinical and dosimetric variables. Even for the >95% of plans meeting QUANTEC rectal criteria, hydrogel spacer provided potentially meaningful benefits.

Gleason pattern 5 is associated with an increased risk for metastasis following androgen deprivation therapy and radiation: An analysis of RTOG 9202 and 9902.

BACKGROUND/PURPOSE: Stratification of Gleason score (GS) into three categories (2-6, 7, and 8-10) may not fully utilize its prognostic discrimination, with Gleason pattern 5 (GP5) previously identified as an independent adverse factor. MATERIALS/METHODS: Patients treated on RTOG 9202 (n = 1292) or RTOG 9902 (n = 378) were pooled and assessed for association of GS and GP5 on biochemical failure (BF), local failure (LF), distant metastasis (DM), and overall survival (OS). Fine and Gray's regression and cumulative incidence methods were used for univariate and multivariate analyses. RESULTS: With median follow-up of 9.4 years, patients with GS 8-10 with GP5 had worse outcome than GS 4 + 4 for DM on both RTOG9202 (p = 0.038) and RTOG9902 (p < 0.001) with a trend toward worse OS (p = 0.059 and p = 0.089, respectively), but without differences in BF or LF. At 10-years DM was higher by 11% (RTOG 9202) and 18% (RTOG 9902) with GP5 compared to GS 4 + 4. On multivariate analysis restricted to long-term androgen deprivation therapy the presence of GP5 substantially increased distant metastasis (HR = 0.43, 95%CI: 0.24-0.76, p = 0.0039) with a trend toward worse OS (HR:0.74, 95% CI:0.54-1.0, p = 0.052) without association with LF (HR:0.55, 95%CI:0.28-1.09, p = 0.085) or BF (HR:1.15, 95%CI:0.84-1.59, p = 0.39). We did not observed substantial differences between Gleason 3 + 5, 5 + 3, or Gleason 9-10. CONCLUSIONS: These results validate GP5 as an independent prognostic factor which is strongest for DM. As a result GP5 should be considered when stratifying patients with GS 8 and may be a patient population in which to evaluate newly approved systemic therapies or additional local treatments.

Trimodality therapy for atypical teratoid/rhabdoid tumor is associated with improved overall survival: A surveillance, epidemiology, and end results analysis.

BACKGROUND: Atypical teratoid/rhabdoid tumors (AT/RTs) are rare aggressive central nervous system tumors. The use of radiation therapy (RT) remains controversial, especially for patients younger than three years of age. The purpose of the current investigation is to robustly analyze the impact of RT among pediatric AT/RT patients using the Surveillance, Epidemiology, and End Results (SEER) database. METHODS: SEER 18 Custom Data registries were queried for AT/RT (ICD-0-3 9508/3). A total of 190 pediatric AT/RT patients were identified, of whom 102 underwent surgery + chemotherapy and 88 underwent trimodality therapy. Univariate and multivariable analyses using Kaplan-Meier and Cox proportional hazards regression modeling were performed. Propensity-score matched analysis with inverse probability of treatment weighting was performed to account for indication bias. The landmark method was used to account for immortal time bias. RESULTS: The majority of patients were <3 years old (75.8%). Patients <3 were more likely to be treated without RT as compared with older patients (62% vs 38%). Doubly robust MVA identified distant disease as a negative prognostic factor (HR 2.1, P = 0.003), whereas trimodality therapy was strongly protective (HR 0.39, P < 0.001). Infants (<1), toddlers (1-2), and older children (3+) all benefited from trimodality therapy, with largest benefit for infants (HR 0.34, P = 0.02) and toddlers (HR 0.31, P < 0.001). CONCLUSION: The current study provides further evidence that trimodality therapy improves clinical outcomes among patients with AT/RT. This finding was most pronounced for younger patients; therefore, further studies are needed to confirm this finding in this vulnerable population.

Spinal Growth Patterns After Craniospinal Irradiation in Children With Medulloblastoma.

PURPOSE: This study aimed to evaluate the impact on spine growth in children with medulloblastoma using either photon or electron craniospinal irradiation (CSI). METHODS AND MATERIALS: This was a single institution retrospective review of children who were treated with CSI for medulloblastoma. Spine growth was measured on magnetic resonance imaging scans at defined locations on the basis of a published predictive model of spine growth after CSI. Differences between spine growth in the anterior, middle, and posterior aspect of the designated vertebral segments were also assessed. Differences between the groups treated with photons or electrons were assessed with student's t test. RESULTS: A total of 19 patients (10 patients treated with electrons and 9 with photons) with a median follow-up time of 45.5 months (confidence interval, 34.9-55.1 months) were evaluated. Patients treated with electrons were younger than those who received photons (5.1 years [range, 3.8-9.0 years] vs 9.6 years [range, 3.5-12.9 years]); however, there were no differences in other clinical characteristics, treatment, or follow-up between the groups. Spine growth rate for patients treated with electrons fit the predictive model (104% ± 5.2%), but patients treated with photons had growth that was faster than predicted by the model (150% ± 47%) and different from that observed with electrons. The differences between treatment the modalities were statistically significant (P = .03). For patients treated with photons, there were no statistical differences between the growth rate of the anterior vertebral body compared with the posterior aspect, but for patients treated with electrons, a faster spine growth in the anterior L1-L5 lumbar spine was observed compared with the posterior lumbar spine (3.90 vs 2.52 mm/year; P = .006) without differences in the cervical or thoracic spine. CONCLUSIONS: The use of electrons to treat the craniospinal axis in children with medulloblastoma resulted in no significant difference in spine growth compared with the predicted spine growth on the basis of previously published models using photons, but with a clinically insignificant faster spine growth rate in the anterior lumbar spine.

Time Interval to Biochemical Failure as a Surrogate End Point in Locally Advanced Prostate Cancer: Analysis of Randomized Trial NRG/RTOG 9202.

BACKGROUND: In prostate cancer, end points that reliably portend prognosis and treatment benefit (surrogate end points) can accelerate therapy development. Although surrogate end point candidates have been evaluated in the context of radiotherapy and short-term androgen deprivation (AD), potential surrogates under long-term (24 month) AD, a proven therapy in high-risk localized disease, have not been investigated. MATERIALS AND METHODS: In the NRG/RTOG 9202 randomized trial (N = 1,520) of short-term AD (4 months) versus long-term AD (LTAD; 28 months), the time interval free of biochemical failure (IBF) was evaluated in relation to clinical end points of prostate cancer-specific survival (PCSS) and overall survival (OS). Survival modeling and landmark analysis methods were applied to evaluate LTAD benefit on IBF and clinical end points, association between IBF and clinical end points, and the mediating effect of IBF on LTAD clinical end point benefits. RESULTS: LTAD was superior to short-term AD for both biochemical failure (BF) and the clinical end points. Men remaining free of BF for 3 years had relative risk reductions of 39% for OS and 73% for PCSS. Accounting for 3-year IBF status reduced the LTAD OS benefit from 12% (hazard ratio [HR], 0.88; 95% CI, 0.79 to 0.98) to 6% (HR, 0.94; 95% CI, 0.83 to 1.07). For PCSS, the LTAD benefit was reduced from 30% (HR, 0.70; 95% CI, 0.52 to 0.82) to 6% (HR, 0.94; 95% CI, 0.72 to 1.22). Among men with BF, by 3 years, 50% of subsequent deaths were attributed to prostate cancer, compared with 19% among men free of BF through 3 years. CONCLUSION: The IBF satisfied surrogacy criteria and identified the benefit of LTAD on disease-specific survival and OS. The IBF may serve as a valid end point in clinical trials and may also aid in risk monitoring after initial treatment.

Patient-Reported Sexual Aid Utilization and Efficacy After Radiation Therapy for Localized Prostate Cancer.

PURPOSE: To report sexual health-related quality of life outcomes and utilization and efficacy of sexual aids in a contemporary cohort of patients treated for localized prostate cancer. PATIENTS AND METHODS: Between 2008 and 2013, 471 consecutive men with localized prostate cancer were treated on 2 institutional protocols (NCT01766492, NCT01618851) or on a prospective institutional registry with patient-reported health-related quality of life. All patients were treated with ultra-hypofractionated radiation therapy. Erectile function (EF) was defined as "firm enough for intercourse" with or without aids per Expanded Prostate Cancer Index Composite-26 (n = 222 at baseline); results apply to this cohort unless specifically noted. Sexual aid utilization and efficacy were patient reported. Multivariable analysis of EF was performed. RESULTS: Median follow-up was 60 months, median age was 67 years, and 70% had intermediate- or high-risk disease per National Comprehensive Cancer Network guidelines. At 24 and 60 months, questionnaire response rates were 86% and 67%, and EF was retained in 53% and 41%, respectively. Baseline sexual aid utilization was 37% (n = 82) and was associated with lower 24-month EF preservation on multivariable analysis (adjusted odds ratio 0.49, 95% confidence interval 0.26-0.92). By 60 months, 70% of men had tried aids. Of those who found aids helpful at baseline, 84% to 89% reported continued benefit at 24 to 60 months. Among aid-naïve patients, efficacy was 80% with first-time use within 12 months and 70% more than 12 months after radiation therapy (P = .02). Among men who developed erectile dysfunction but found sexual aids helpful, 25% were not current users at 60 months. CONCLUSIONS: One-third of men used sexual aids at baseline, which doubled by 5 years after radiation therapy. Self-reported efficacy was high and sustained. Despite significant declines in EF, a number of men reported helpfulness of aids but were not active users. Future study is required to understand drivers of aid utilization to optimize posttreatment sexual function.

Double-blind placebo-controlled multicenter phase II trial to evaluate D-methionine in preventing/reducing oral mucositis induced by radiation and chemotherapy for head and neck cancer.

BACKGROUND: The purpose of this study was to test if oral D-methionine (D-met) reduced mucositis during chemoradiotherapy. METHODS: We conducted a placebo-controlled double-blind randomized phase II trial of D-met (100 mg/kg p.o. b.i.d.) testing the rate of severe (grades 3-4) mucositis. RESULTS: Sixty patients were randomized. Grade 2 + oral pain was higher with placebo (79% vs 45%; P = .0165), whereas grade 2 + body odor was greater with D-met (3% vs 41%; P = .0015). Mucositis was decreased with D-met by the physician (World Health Organization [WHO], P = .007; Radiation Therapy Oncology Group [RTOG], P = .009) and patient functional scales (RTOG, P = .0023). The primary end point of grades 3 to 4 mucositis on the composite scale demonstrated a decrease with D-met (48% vs 24%; P = .058), which was borderline in significance. A planned secondary analysis of a semiquantitative scoring system noted decreased oral ulceration (2.2 vs 1.5; P = .023) and erythema (1.6 vs 1.1; P = .048) with D-met. CONCLUSION: Although not meeting the primary end point, results of multiple assessments suggest that D-met decreased mucositis.

Changes in prostate orientation due to removal of a Foley catheter.

PURPOSE: Investigate the impact on prostate orientation caused by use and removal of a Foley catheter, and the dosimetric impact on men prospectively treated with prostate stereotactic body radiotherapy (SBRT). METHODS: Twenty-two men underwent a CT simulation with a Foley in place (FCT), followed immediately by a second treatment planning simulation without the Foley (TPCT). The change in prostate orientation was determined by rigid registration of three implanted transponders between FCT and TPCT and compared to measured orientation changes during treatment. The impact on treatment planning and delivery was investigated by analyzing the measured rotations during treatment relative to both CT scans, and introducing rotations of ±15° in the treatment plan to determine the maximum impact of allowed rotations. RESULTS: Removing the Foley caused a statistically significant prostate rotation (P < 0.0028) compared to normal biological motion in 60% of patients. The largest change in rotation due to removing a Foley occurs about the left-right axis (tilt) which has a standard deviation two to five times larger than changes in rotation about the Sup-Inf (roll) and Ant-Post (yaw) axes. The change in tilt due to removing a Foley for prone and supine patients was -1.1° ± 6.0° and 0.3° ± 7.4°, showing no strong directional bias. The average tilt during treatment was -1.6° ± 7.1° compared to the TPCT and would have been -2.0° ± 7.1° had the FCT been used as the reference. The TPCT was a better or equivalent representation of prostate tilt in 82% of patients, vs 50% had the FCT been used for treatment planning. However, 92.7% of fractions would still have been within the ±15° rotation limit if only the FCT were used for treatment planning. When rotated ±15°, urethra V105% = 38.85Gy  < 20% was exceeded in 27% of the instances, and prostate (CTV) coverage was maintained above D95%  > 37 Gy in all but one instance. CONCLUSIONS: Removing a Foley catheter can cause large prostate rotations. There does not appear to be a clear dosimetric benefit to obtaining the CT scan with a Foley catheter to define the urethra given the changes in urethral position from removing the Foley catheter. If urethral sparing is desired without the use of a Foley, utilization of an MRI to define the urethra may be necessary, or a pseudo-urethral planning organ at risk volume (PRV) may be used to limit dosimetric hot spots.

A multi-institutional phase 2 trial of prostate stereotactic body radiation therapy (SBRT) using continuous real-time evaluation of prostate motion with patient-reported quality of life.

PURPOSE: The use of stereotactic body radiation therapy (SBRT) for prostate cancer has been reported predominantly from single institutional studies, although concerns for broader adoption exist. METHODS AND MATERIALS: From 2011 through 2013, 66 men were accrued to a phase 2 trial at 5 centers. SBRT consisted of 5 fractions of 7.4 Gy to a total dose of 37 Gy using conventional linear accelerators. Electromagnetic transponders were used for motion management. Health-related quality of life (HRQOL) was evaluated via the Expanded Prostate Cancer Index Composite 26 questionnaire. Acute and late toxicities were collected according to Common Terminology Criteria for Adverse Events, version 4.0. Linear mixed modeling was performed to assess changes in HRQOL over time. RESULTS: Median follow-up was 36 months. All men had low- or intermediate-risk disease. There have been 0 biochemical recurrences. No grade 3 urinary or bowel toxicity was reported. Twenty-three percent of patients had acute grade 2 urinary toxicity, with 9% late grade 2 urinary toxicity. Four percent and 5% experienced acute or late grade 2+ bowel toxicity, respectively. Urinary bother and bowel HRQOL transiently decreased during the first 6 to 12 months post-SBRT, and then returned to baseline. In men with good erectile function at baseline, sexual HRQOL declined during the first 6 months and stabilized thereafter. On linear mixed modeling, the strongest predictor of sustained bowel and sexual HRQOL was baseline HRQOL. CONCLUSIONS: In this multi-institutional phase 2 clinical trial using continuous real-time evaluation of prostate motion, prostate SBRT has excellent intermediate-term tumor control with mild and expected treatment-related side effects.