Postprostatectomy Intensity-modulated Radiation Therapy Research Articles

Comparative toxicity outcomes of proton-beam therapy versus intensity-modulated radiotherapy for prostate cancer in the postoperative setting.

Despite increasing utilization of proton-beam therapy (PBT) in the postprostatectomy setting, no data exist regarding toxicity outcomes relative to intensity-modulated radiotherapy (IMRT). The authors compared acute and late genitourinary (GU) and gastrointestinal (GI) toxicity outcomes in patients with prostate cancer (PC) who received treatment with postprostatectomy IMRT versus PBT. With institutional review board approval, patients with PC who received adjuvant or salvage IMRT or PBT (70.2 gray with an endorectal balloon) after prostatectomy from 2009 through 2017 were reviewed. Factors including combined IMRT and PBT and/or concurrent malignancies prompted exclusion. A case-matched cohort analysis was performed using nearest-neighbor 3-to-1 matching by age and GU/GI disorder history. Logistic and Cox regressions were used to identify univariate and multivariate associations between toxicities and cohort/dosimetric characteristics. Toxicity-free survival (TFS) was assessed using the Kaplan-Meier method. Three hundred seven men (mean±SD age, 59.7±6.3years; IMRT, n=237; PBT, n=70) were identified, generating 70 matched pairs. The median follow-up was 48.6 and 46.1months for the IMRT and PBT groups, respectively. Although PBT was superior at reducing low-range (volumes receiving 10% to 40% of the dose, respectively) bladder and rectal doses (all P ≤ .01), treatment modality was not associated with differences in clinician-reported acute or late GU/GI toxicities (all P≥.05). Five-year grade ≥2 GU and grade ≥1 GI TFS was 61.1% and 73.7% for IMRT, respectively, and 70.7% and 75.3% for PBT, respectively; and 5-year grade ≥3 GU and GI TFS was >95% for both groups (all P≥.05). Postprostatectomy PBT minimized low-range bladder and rectal doses relative to IMRT; however, treatment modality was not associated with clinician-reported GU/GI toxicities. Future prospective investigation and ongoing follow-up will determine whether dosimetric differences between IMRT and PBT confer clinically meaningful differences in long-term outcomes.

Patient-reported Outcomes and Late Toxicity After Postprostatectomy Intensity-modulated Radiation Therapy

BackgroundLimited long-term data characterize patient-reported quality of life (QOL) following postprostatectomy intensity-modulated radiation therapy (PPRT), and predictors of decline are poorly defined. ObjectiveTo identify modifiable dosimetric and clinical risk factors impacting QOL and late toxicity following PPRT. Design, setting, and participantsA prospective cohort study of consecutive men with prostate cancer who received PPRT between 2007 and 2015 at a single academic institution. InterventionPatients were prospectively evaluated using the Expanded Prostate Cancer Index Composite (EPIC-26) QOL instrument. Radiation Therapy Oncology Group/Common Toxicity Criteria for Adverse Events toxicity grades were assigned at every follow-up visit. Treatment was delivered to the prostate bed (median 68Gy)±pelvic lymphatics (65%, median 50.4Gy) with daily image guidance. Androgen deprivation therapy was concomitantly administered to 132 (66%) men for a median of 4mo. Outcome measurements and statistical analysisChanges were deemed relevant if they exceeded the minimally clinically important difference (MCID), as calculated by a distribution-based method. Generalized estimating equation models and Cox regression were used for QOL and late toxicity univariate and multivariable analysis. Results and limitationsOverall, 199 men were identified with a median follow-up of 33mo. Overall urinary function (UF), bowel function (BF), sexual function (SF), and urinary irritation/obstruction (UI/UO) scores were never lower than the MCID. Between 8% and 18% of men experienced a small multidomain (1× MCID) decline, and 0–8% experienced a moderate multidomain decline (2× MCID) at a given time point up to 84mo after PPRT. The rates of freedom from grade 2 or higher (Gr2+) genitourinary (GU) and gastrointestinal (GI) toxicity were 94% and 95%, respectively, at 4yr. Factors associated with worse QOL or toxicity included longer time to PPRT (UC and UF), higher BMI (UF, BF, and late GI toxicity), older age (BF, SF, and late GU toxicity); hormone therapy (SF), total dose (late GI toxicity), tobacco history (BF), and higher bladder V70Gy (UC, UF, and late GU toxicity). ConclusionsLong-term QOL and late toxicity are favorable following postprostatectomy radiation therapy. Identifiable clinical and dosimetric risk factors may guide decision making to optimize urinary, sexual, and bowel function. Patient summaryThe following study provides a detailed report of favorable patient-reported quality of life and late side-effect profiles of radiation therapy following surgery for localized prostate cancer. Our findings provide patients guidance on what symptoms to expect if they are planning to undergo radiation therapy in this setting. It also allows physicians to counsel patients appropriately, and modify certain clinical and radiation-related risk factors to optimize quality of life.

717 - Dose-effect relationship for 1-year incontinence after post-prostatectomy intensity-modulated radiotherapy (MRT)

717 - Dose-effect relationship for 1-year incontinence after post-prostatectomy intensity-modulated radiotherapy (MRT)

A Prospective Cohort Study of Patient Reported Outcomes and Late Toxicity in Patients Receiving Post-Prostatectomy Intensity Modulated Radiation Therapy (IMRT)

A Prospective Cohort Study of Patient Reported Outcomes and Late Toxicity in Patients Receiving Post-Prostatectomy Intensity Modulated Radiation Therapy (IMRT)

Late toxicity after post-prostatectomy intensity modulated radiation therapy: Evaluating normal-tissue sparing guidelines

PurposeDose-volume histogram (DVH) toxicity relationships are poorly defined in men who receive radiation after radical prostatectomy (RP). We evaluated Radiation Therapy Oncology Group (RTOG) study 0534 and institutional intact normal-tissue sparing guidelines, as well as dose to bladder trigone, for ability to minimize late toxicity. Methods and materials164 men received intensity modulated radiation therapy (RT) to a median prostate bed dose of 66.6 Gy at a median of 22 months after RP. 46% of men were prescribed androgen deprivation therapy and pelvic lymph node irradiation to a median dose of 50.4 Gy. DVH relationships for the rectum, bladder, trigone, and bladder excluding the clinical target volume (bladder-CTV) were analyzed against the Common Terminology Criteria for Adverse Events late grade 2 + (G2+) gastrointestinal (GI) and genitourinary (GU) toxicity by log-rank test. RTOG 0534 (rectum V65, 40 Gy ≤35, 55%, and bladder-CTV V65, 40 ≤50, 70%) and intact prostate RT institutional guidelines (rectum V70, 65, 40 ≤20, 40, 80% and bladder V70, 65, 40 ≤30, 60, 80%, respectively) guidelines were evaluated. ResultsWith a median follow-up time of of 33 months, the 4-year freedom from G2 + GI and GU toxicity were both 91%. G2 + GI (n = 12) and GU (n = 15) toxicity included 4% diarrhea (n = 6), 4% hemorrhage (n = 6), 1% proctitis (n = 1), and 4% urinary frequency (n = 7), 1% obstructive (n = 2), 2% cystitis (n = 3), and 3% incontinence (n = 5), respectively. RTOG 0534 rectum and bladder goals were not achieved in 65% and 41% of cases, while the institutional intact prostate goals were not achieved in 21% and 25% of cases, respectively. Neither dose to the bladder trigone nor any of the proposed normal tissue goals were associated with late toxicity (P > .1). In the univariate analysis, age, pelvic RT, RT dose, anticoagulation use, androgen deprivation therapy, time from RP to RT, and tobacco history were not associated with toxicity. ConclusionsMore than 90% of men were free from late G2 + toxicity 4 years after post-RP intensity modulated RT. No tested parameters were associated with late toxicity. In the absence of established normal-tissue DVH guidelines in the postoperative setting, the use of intact guidelines is reasonable.

A Pilot Study: The Role of Radio-Opaque Hydrogel Tissue Marker in the Treatment of Postprostatectomy Intensity Modulated Radiation Therapy

It is well documented that the prostate bed is highly susceptible to inter-fraction motion leading to larger treatment planning margins to account for daily treatment set up uncertainties when matching to bony anatomy. The use of fiducial markers in the prostate bed has significantly improved accuracy of treatment delivery. This pilot study aims to investigate the role and benefits of radio-opaque hydrogel tissue marker in the treatment of post prostatectomy intensity modulated radiation therapy (IMRT). Twenty patients treated with IMRT to a dose of 70.2Gy in 39 fractions between Jan 2016 to Jan 2017 were included in this study. All patients underwent transperineal injection of hydrogel tissue marker at the level of vesico-urethral anastomosis and cystoscopically into the posterior bladder wall. Instructions for bladder and bowel preparation to be followed during CT simulation and daily treatments were provided to the patients. Daily on-line cone beam CT matching to the hydrogel tissue marker was performed prior to each treatment and off-sets relative to skin tattoos were recorded in 3 directions: left-right (LR); superior-inferior (SI) and anterio-posterior (AP). Daily image registration using bony matching was then assessed off-line and off-sets relative to skin tattoos were again recorded. The mean and standard deviation of the differences between the hydrogel tissue markers and bony off-sets were calculated for all fractions for each patient; then the overall mean and systematic (Σ) and random errors (σ) for the entire cohort were calculated. The planning target volume (PTV) margin required for bony matching was estimated using van Herk's formula of 2.5Σ + 0.7σ, which is designed to ensure a minimum dose of 95% of prescribed dose to the clinical target volume (CTV) in 90% of patients. These margins are relative to the hydrogel tissue markers which are assumed to be in the target tissue. A total of 1520 images were analysed. The overall mean shift differences between the hydrogel tissue markers and bones for the entire cohort were LR: 0.13mm (Σ 0.38mm, σ 1.35mm); SI: 0.92mm (Σ 1.40mm, σ 2.50mm) and AP: 0.40mm (Σ 1.98mm, σ 3.18mm). The calculated PTV margins for bony matching relative to hydrogel tissue markers were 1.90mm in LR, 5.25mm in SI and 7.17mm AP directions. Prostate bed motion is independent of pelvic bone anatomy and soft tissue matching has shown to be superior compared with pelvic bone matching. With a required PTV margin of 7.17mm in the AP direction, the use of hydrogel tissue marker can significantly improve treatment set up accuracy even in patients with optimal bowel and bladder preparations who undergo image guidance with pelvic bone matching. This will provide the best CTV coverage whilst minimising the current PTV margin and mitigating bladder and rectal toxicities.

Quality of Life after post-prostatectomy intensity modulated radiation therapy to the prostate bed with or without the use of gold fiducial markers for image guidance or higher total radiotherapy doses.

ABSTRACTPurpose To evaluate quality of life (QoL) after post-prostatectomy intensity modulated radiation therapy (IMRT) in the “adjuvant” setting starting within 4 months of radical prostatectomy for adverse features; and “salvage” setting for a PSA≥0.2ng/mL.Materials and Methods Retrospective review of 130 patients who underwent IMRT to the prostate bed±gold fiducial marker placement for image guidance to 64.8-72.0Gy (median, 70.2Gy) between 2004 and 2013. Higher doses were defined as 70.2-72.0Gy and lower doses were defined as 64.8-68.4Gy. Androgen deprivation therapy (ADT) was given to 4/48 (8%) adjuvant patients and 9/82 (11%) salvage patients. International Prostate Symptom Score (IPSS), Sexual Health Inventory for Men (SHIM), and Expanded Prostate Cancer Index Composite-26-bowel (EPIC-26-bowel) questionnaires were used to assess urinary, sexual, and bowel QoL, respectively.Results Median follow-up was 46 months. There were better urinary (p=0.03) and sexual (p=0.002) QoL scores with adjuvant IMRT relative to salvage IMRT. The use of prostate bed fiducial markers did not significantly affect urinary, sexual, or bowel QoL (p=0.39, p=0.49, and p=0.40, respectively). Higher total radiotherapy doses did not significantly affect urinary, sexual, or bowel QoL (p=0.21, p=0.61, and p=0.36, respectively).Conclusions There was no significant change in urinary, sexual, and bowel sexual QoL with post-prostatectomy IMRT regardless of whether prostate bed fiducial markers or higher total radiotherapy doses were used. QoL with IMRT in the present study compares favorably with prior reports for three-dimensional conformal radiation therapy.

Urinary and bowel quality of life after image-guided, intensity modulated radiation therapy to the prostate bed.

312 Background: Majority of patients with adverse pathological features on radical prostatectomy do not receive post-prostatectomy radiation due to concerns of negative impact on their quality of life (QOL). The purpose of this study is to evaluate QOL after post-prostatectomy intensity modulated radiation therapy (IMRT) in the “adjuvant”(ADJ) setting for positive surgical margins, extraprostatic extension, or seminal vesicle invasion with a PSA < 0.2 ng/mL and a “salvage”(SAL) setting for a PSA ≥ 0.2 ng/mL at the start of IMRT. Methods: Between 2004 and 2013, 130 patients underwent IMRT to the prostate bed. Sexual Health Inventory for Men (SHIM), International Prostate Symptom Score (IPSS), and Expanded Prostate cancer Index Composite-26 for bowel (EPIC-26-bowel) scores were recorded before radiation and at 3-month intervals after completion of treatment to assess sexual, urinary, and rectal QOL, respectively. A mixed model for repeated measurements was used to compare QOL scores over time among various subgroups. Results: ADJ and SAL radiation were delivered to 48 (37%), 82 (63%) respectively. Total radiotherapy doses were 64.8-68.4 Gy using 1.8-Gy daily in 56 (43%) patients and 70.2-72.0 Gy in 74 (57%) patients. Androgen deprivation therapy (ADT) was given to 4/48 (8%) ADJ patients and 9/82 (11%) SAL patients. Fiducials were placed in prostate bed for image guidance in 42 (32%) patients. Median follow up was 46 months. Total radiation dose did not significalntly affect QOL. SAL IMRT was associated with worse mean SHIM scores (3 points, p = 0.002) and ADJ IMRT was associated with lower mean IPSS scores (2 points, p = 0.03). Mean EPIC-26-bowel scores were lower without fiducial markers (16 points, p < 0.0001). Conclusions: SAL IMRT was associated with worse sexual QOL, possibly due to less frequent usage of phosphodiesterase-5 inhibitors. ADJ IMRT was associated with worse urinary QOL, possibly due to a shorter post-operative recovery period. Fiducial marker resulted in better rectal QOL due to greater rectal sparing. Urinary and rectal QOL with post-prostatectomy, image-guided IMRT compare favorably with previous QOL reports involving three-dimensional conformal radiation therapy.

Bladder dose-volume parameters are associated with urinary incontinence after postoperative intensity modulated radiation therapy for prostate cancer

PurposeUrinary incontinence is a potential side effect of prostatectomy and intensity modulated radiation therapy (IMRT) for prostate cancer. There are limited data on dosimetric parameters that may predict for poor continence recovery in men who receive postoperative IMRT. Methods and materialsEighty-seven men with nonmetastatic prostate cancer who underwent prostatectomy followed by adjuvant (13%) or salvage (87%) IMRT were identified. The Expanded Prostate Cancer Index composite questionnaire was prospectively collected at baseline, 6 weeks, and 6, 12, 18, 24, 36, and 48 months post-IMRT. Relevant critical structures were contoured and dose-volume metrics collected. The primary endpoint was urinary continence global score. Longitudinal analysis using a generalized estimating equation model was performed. ResultsThere was no statistically significant change in Expanded Prostate Cancer Index composite urinary continence global scores over time as compared with baseline (all P > .05). In univariate analysis, bladder volume receiving 70 Gy (V70 Gy) and penile bulb V70 Gy were associated with urinary continence (odds ratio, 0.82; P < .05). In a multivariable model that included body mass index, distance between vesicourethral junction and genitourinary diaphragm, time from surgery, use of antihypertensive medications, age, diabetes, and bladder V70 Gy, only bladder V70 Gy (odds ratio, 0.82; P = .03) was associated with outcome. After 2 years, there was a significant difference in global score for those with V70 Gy < 42.27 versus ≥42.27 mL (all P < .05 at 2 and 3 years post-IMRT). ConclusionThere was no significant change in patient-reported urinary continence scores after postprostatectomy IMRT. Bladder V70 Gy was independently associated with a decrease in urinary continence scores. Further evaluation is necessary to optimize quality of life in these men.

Image Guided Hypofractionated Postprostatectomy Intensity Modulated Radiation Therapy for Prostate Cancer

Hypofractionated radiation therapy (RT) has promising long-term biochemical relapse-free survival (bRFS) with comparable toxicity for definitive treatment of prostate cancer. However, data reporting outcomes after adjuvant and salvage postprostatectomy hypofractionated RT are sparse. Therefore, we report the toxicity and clinical outcomes after postprostatectomy hypofractionated RT. From a prospectively maintained database, men receiving image guided hypofractionated intensity modulated RT (HIMRT) with 2.5-Gy fractions constituted our study population. Androgen deprivation therapy was used at the discretion of the radiation oncologist. Acute toxicities were graded according to the Common Terminology Criteria for Adverse Events version 4.0. Late toxicities were scored using the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer scale. Biochemical recurrence was defined as an increase of 0.1 in prostate-specific antigen (PSA) from posttreatment nadir or an increase in PSA despite treatment. The Kaplan-Meier method was used for the time-to-event outcomes. Between April 2008 and April 2012, 56 men received postoperative HIMRT. The median follow-up time was 48 months (range, 21-67 months). Thirty percent had pre-RT PSA <0.1; the median pre-RT detectable PSA was 0.32 ng/mL. The median RT dose was 65 Gy (range, 57.5-65 Gy). Ten patients received neoadjuvant and concurrent hormone therapy. Posttreatment acute urinary toxicity was limited. There was no acute grade 3 toxicity. Late genitourinary (GU) toxicity of any grade was noted in 52% of patients, 40% of whom had pre-RT urinary incontinence. The 4-year actuarial rate of late grade 3 GU toxicity (exclusively gross hematuria) was 28% (95% confidence interval [CI], 16%-41%). Most grade 3 GU toxicity resolved; only 7% had persistent grade ≥3 toxicity at the last follow-up visit. Fourteen patients experienced biochemical recurrence at a median of 20 months after radiation. The 4-year bPFS rate was 75% (95% CI, 63%-87%). The biochemical control in this series appears promising, although relatively short follow-up may lead to overestimation. Late grade 3 GU toxicity was higher than anticipated with hypofractionated radiation of 65 Gy to the prostate bed, although most resolved.

Quality of Life after Post-Prostatectomy Intensity Modulated Radiation Therapy: Pelvic Nodal Irradiation Is Not Associated with Worse Bladder, Bowel, or Sexual Outcomes.

BackgroundLimited data exist regarding toxicity and quality of life (QOL) after post-prostatectomy intensity modulated radiation therapy (IMRT) and whether pelvic nodal RT influences these outcomes.Methods118 men were treated with curative-intent RT after radical prostatectomy. 69 men (58%) received pelvic nodal RT. QOL data and physician-assigned toxicity were prospectively collected. Changes in QOL from baseline were assessed with Wilcoxon signed-rank tests and risk factors associated with each domain were identified with generalized estimating equation (GEE) models. Late freedom from (FF) toxicity was estimated by the Kaplan-Meier method and comparisons were tested using the log-rank test.ResultsUrinary irritation/obstruction, bowel, and sexual domain scores declined at 2 months (all P ≤ 0.01) but were no different than baseline at subsequent visits through 4 years of follow-up. At 4 years, FF grade 2+ GI toxicity was 90% and FF grade 2+ GU toxicity was 89%. On GEE analysis, pelvic nodal RT was associated with decreased bowel function (P = 0.09) and sexual function (P = 0.01). On multivariate analysis, however, there was no significant association with either decreased bowel (P = 0.31) or sexual (P = 0.84) function. There was also no association with either FF grade 2+ GI toxicity (P = 0.24) or grade 2+ GU toxicity (P = 0.51).ConclusionsReceipt of pelvic nodal RT was not associated with inferior QOL or toxicity compared to prostate bed alone RT. For the entire cohort, RT was associated with only temporary declines in patient-reported urinary, bowel, or sexual QOL.

Determining optimal planning target volume and image guidance policy for post-prostatectomy intensity modulated radiotherapy.

BackgroundThere is limited information available on the optimal Planning Target Volume (PTV) expansions and image guidance for post-prostatectomy intensity modulated radiotherapy (PP-IMRT). As the prostate bed does not move in a uniform manner, there is a rationale for anisotropic PTV margins with matching to soft tissue. The aim of this study is to find the combination of PTV expansion and image guidance policy for PP-IMRT that provides the best balance of target coverage whilst minimising dose to the organs at risk.MethodsThe Cone Beam CT (CBCT) images (n = 377) of 40 patients who received PP-IMRT with daily online alignment to bony anatomy (BA) were reviewed. Six different PTV expansions were assessed: 3 published PTV expansions (0.5 cm uniform, 1 cm uniform, and 1 + 0.5 cm posterior) and 3 further anisotropic PTV expansions (Northern Sydney Cancer Centre (NSCC), van Herk, and smaller anisotropic). Each was assessed for size, bladder and rectum coverage and geographic miss. Each CBCT was rematched using a superior soft tissue (SST) and averaged soft tissue (AST) match. Potential geographic miss was assessed using all PTV expansions except the van Herk margin.ResultsThe 0.5 cm uniform expansion yielded the smallest PTV (median volume = 222.3 cc) and the 1 cm uniform expansion yielded the largest (361.7 cc). The Van Herk expansion includes the largest amount of bladder (28.0 %) and rectum (36.0 %) and the 0.5 cm uniform expansion the smallest (17.1 % bladder; 10.2 % rectum). The van Herk PTV expansion had the least geographic miss with BA matching (4.2 %) and the 0.5 cm uniform margin (28.4 %) the greatest. BA matching resulted in the highest geographic miss rate for all PTVs, followed by SST matching and AST matching. Changing from BA to an AST match decreases potential geographic miss by half to two thirds, depending on the PTV expansion, to <10 % for all PTV expansions. When using the smaller anisotropic PTV expansion, AST matching would reduce the geographic miss rate from 21.0 % with BA matching down to 5.6 %.ConclusionsOur results suggest the optimal PTV expansion and image guidance policy for PP-IMRT is daily average soft tissue matching using CBCT scans with a small anisotropic PTV expansion of 0.5 cm in all directions apart from a 1 cm expansion in the anterior-posterior direction in the upper prostate bed. Care must be taken to ensure adequate training of Radiation Therapists to perform soft tissue matching with CBCT scans.

Evaluation of 3 T pelvic MRI imaging in prostate cancer patients receiving postprostatectomy IMRT.

242 Background: The purpose of the study was to evaluate the utility of a 3 T pelvic magnetic resonance imaging (MRI) in detecting a local recurrence in post-prostatectomy prostate cancer patients prior to receiving adjuvant or salvage intensity-modulated radiation therapy (IMRT). Methods: Ninety prostate cancer patients status post-prostatectomy with rising prostate-specific antigen (PSA) had a 3 T pelvic MRI prior to IMRT. The following variables were analyzed for predicting positive findings on MRI: initial presenting and initial post-op PSA, PSA at the time of imaging, PSA velocity, surgical margins, Gleason score, pathological stage, pre-RT digital rectal examination, and type of surgical prostatectomy. Results: The only significant variable predictive of a positive MRI was positive margins. Specifically, 15 of 46 (33 %) patients with positive margins had a positive MRI, while 5 of 44 (11 %) patients with negative margins had a positive MRI. In the MRI positive group, the location of the positive findings on MRI corresponded with the pathology report in 9 of 12 (75 %) cases. Conclusions: Post-prostatectomy patients with pathologic positive margins are three times more likely to have positive findings on a 3 T MRI. [Table: see text]

A Comparison of Urinary and Sexual Function Patient-Reported Outcomes (PROs) Among Treatment Modalities for Prostate Cancer (PCa)

Trends in PROs for treatment modalities in localized PCa are poorly understood. We aim to report trends in PROs for urinary and sexual function using American Urologic Association Symptom Score (AUA) and Sexual Health Inventory for Men (SHIM) comparing intensity modulated radiation therapy (IMRT), low dose rate brachytherapy (LDR), post-prostatectomy IMRT (PPRT), and radical prostatectomy (RP).

Evaluation of 3 T pelvic MRI imaging in prostate cancer patients receiving post-prostatectomy IMRT

The purpose of the study was to evaluate the utility of a 3 T pelvic magnetic resonance imaging (MRI) in detecting a local recurrence in post-prostatectomy prostate cancer patients prior to receiving adjuvant or salvage intensity-modulated radiation therapy (IMRT). Ninety prostate cancer patients status post-prostatectomy with rising prostate-specific antigen (PSA) had a 3 T pelvic MRI prior to IMRT. The following variables were analyzed for predicting positive findings on MRI: initial presenting and initial post-op PSA, PSA at the time of imaging, PSA velocity, surgical margins, Gleason score, pathological stage, pre-RT digital rectal examination, and type of surgical prostatectomy. The only significant variable predictive of a positive MRI was positive margins. Specifically, 15 of 46 (33 %) patients with positive margins had a positive MRI, while 5 of 44 (11 %) patients with negative margins had a positive MRI. In the MRI positive group, the location of the positive findings on MRI corresponded with the pathology report in 9 of 12 (75 %) cases. Post-prostatectomy patients with pathologic positive margins are three times more likely to have positive findings on a 3 T MRI.

The impact of rectal and bladder variability on target coverage during post-prostatectomy intensity modulated radiotherapy

Background and purposeAccuracy when delivering post-prostatectomy intensity modulated radiotherapy (IMRT) is crucial. The aims of this study were to quantify prostate bed movement and determine what amount of bladder or rectum size variation creates the potential for geographic miss. Methods and materialsThe Cone Beam CT (CBCT) images (n=377) of forty patients who received post-prostatectomy IMRT with daily on-line alignment to bony anatomy were reviewed. Prostate bed movement was estimated using the location of surgical clips in the upper and lower sections of the PTV and correlated with rectal and bladder filling (defined as changes in the cross sectional diameter at defined levels). The number of potential geographic misses caused by bladder and rectum variation was calculated assuming a uniform CTV to PTV expansion of 1cm except 0.5cm posteriorly. ResultsVariations in bladder filling of >2cm larger, ±1cm, or >2cm smaller occurred in 3.4%, 56.2%, and 15.1% of images respectively with potential geographic misses in the upper prostate bed of 61.5%, 9.9% and 26.3% respectively. Variations in rectal filling in the upper prostate bed of >1.5cm larger, 1.5cm larger to 1cm smaller, and >1cm smaller occurred in 17.2%, 75.6%, and 7.2% of images respectively. These variations resulted in geographic misses in the upper prostate bed in 29.2%, 12.3%, and 63.0% of images respectively. Variations in bladder and rectal filling in the lower prostate bed region had minimal impact on geographic misses. ConclusionsBladder and rectal size changes at treatment affect prostate bed coverage, especially in the upper aspect of the prostate bed. The greatest potential for geographic miss occurred when either the bladder increased in size or when the rectum became smaller. Ensuring a full bladder and empty rectum at simulation will minimise this risk. Our data also support anisotropic PTV margins with larger margins superiorly than inferiorly.

The importance of prostate bed tilt during postprostatectomy intensity-modulated radiotherapy

Variations in rectal and bladder filling can create a tilt of the prostate bed, which generates the potential for a geographic miss during postprostatectomy radiotherapy. The aim of this study is to assess the effect that bladder and rectum filling has on planning target volume angle, to determine a method to assess prostate bed tilt leading to potential geographic miss, and to discuss possible implementation issues. The cone-beam computed tomography images (n = 377) of 40 patients who received postprostatectomy radiotherapy with intensity-modulated radiotherapy were reviewed. The amount of tilt in the prostate bed was defined as the angle change between 2 surgical clips, one in the upper prostate bed and another in the lower. A potential geographic miss was defined as movement of any clip of more than 1cm in any direction or 0.5cm posteriorly when aligned to bone anatomy. Variations in bladder and rectum size were correlated with the degree of prostate bed tilt, and the rate of potential geographic miss was determined. A possible clinical use of prostate bed tilt was then assessed for different imaging techniques. A tilt of more than 10° was seen in 20.2% of images, which resulted in a 57.9% geographic miss rate of the superior clip. When tilt remained within 10°, there was only a 9% rate of geographic miss. Potential geographic miss of the inferior surgical clip was rare, occurring in only 1.9% of all images reviewed. The most common occurrence when the prostate bed tilt increased by more than 10° was a smaller bladder and larger rectum (6.4% of all images). The most common occurrence when the prostate bed tilt decreased by more than 10° was a larger bladder and smaller rectum (1.3% of all images). Significant prostate bed tilt (>± 10°) occurred in more than 20% of images, creating a 58% rate of geographic miss. Greatest prostate bed tilt occurred when the bladder size increased or reduced by more than 2cm or the superior rectum size increased by more than 1.5cm or reduced by more than 1cm from the planned size. Using prostate bed tilt could be an effective measurement for assessing potential geographic miss on orthogonal images if volumetric imaging is unavailable.

Comparative Effectiveness of Intensity-Modulated Radiotherapy and Conventional Conformal Radiotherapy in the Treatment of Prostate Cancer After Radical Prostatectomy

Comparative effectiveness research of prostate cancer therapies is needed because of the development and rapid clinical adoption of newer and costlier treatments without proven clinical benefit. Radiotherapy is indicated after prostatectomy in select patients who have adverse pathologic features and in those with recurrent disease. To examine the patterns of use of intensity-modulated radiotherapy (IMRT), a newer, more expensive technology that may reduce radiation dose to adjacent organs compared with the older conformal radiotherapy (CRT) in the postprostatectomy setting, and to compare disease control and morbidity outcomes of these treatments. Data from the Surveillance, Epidemiology, and End Results-Medicare-linked database were used to identify patients with a diagnosis of prostate cancer who had received radiotherapy within 3 years after prostatectomy. Patients who received IMRT or CRT. The outcomes of 457 IMRT and 557 CRT patients who received radiotherapy between 2002 and 2007 were compared using their claims through 2009. We used propensity score methods to balance baseline characteristics and estimate adjusted incidence rate ratios (RRs) and their 95% CIs for measured outcomes. Use of IMRT increased from zero in 2000 to 82.1% in 2009. Men who received IMRT vs CRT showed no significant difference in rates of long-term gastrointestinal morbidity (RR, 0.95; 95% CI, 0.66-1.37), urinary nonincontinent morbidity (0.93; 0.66-1.33), urinary incontinence (0.98; 0.71-1.35), or erectile dysfunction (0.85; 0.61-1.19). There was no significant difference in subsequent treatment for recurrent disease (RR, 1.31; 95% CI, 0.90-1.92). Postprostatectomy IMRT and CRT achieved similar morbidity and cancer control outcomes. The potential clinical benefit of IMRT in this setting is unclear. Given that IMRT is more expensive, its use for postprostatectomy radiotherapy may not be cost-effective compared with CRT, although formal analysis is needed.

Health‐related quality of life using intensity‐modulated radiation therapy for post‐prostatectomy radiotherapy

Post-prostatectomy radiotherapy (PPRT) with intensity-modulated radiation therapy (IMRT) has the potential to decrease toxicity by reducing dose to surrounding structures. We assessed its impact on health-related quality of life (HRQoL). PPRT patients were enrolled in a prospective HRQoL database. To be eligible, patients were required to be treated with IMRT and have a minimum of 15-month follow up. HRQoL was assessed at baseline, 3, 9 and 15-24 months using the Expanded Prostate Cancer Index Composite questionnaire. Higher scores reflected better HRQoL. Results were analysed as both population means and as individual scores where a moderate change was 10-20 points and a substantial change was >20 points. There were 64 patients eligible and 83% of the cohort received salvage radiotherapy. Prescribed dose was 64 Gy in 32 fractions for adjuvant and 66 Gy in 33 fractions for salvage IMRT. Mean function scores for urinary, bowel and sexual domains were similar at baseline and 15 months (83.5, 94.2 and 16.9 vs. 82.2, 93.1 and 14.3, respectively). Mean global physical functioning (51.0 vs. 48.1) and mental functioning (51.6 vs. 54.2) showed no difference over time. Individual patient scores by 2 years showed a >20-point deterioration in urinary (12.5%), bowel (1.6%), sexual function (9.4%), physical functioning (3.1%) and mental functioning (1.6%). This report on HRQoL following post-prostatectomy IMRT demonstrates no variation in mean scores in any domain and only 1.6% of patients reporting a greater than 20-point deterioration between baseline and 15-24 months in bowel function.

Endorectal balloon reduces anorectal doses in post-prostatectomy intensity-modulated radiotherapy

Background and purposeTo investigate the effect of an endorectal balloon (ERB) on anal wall (Awall) and rectal wall (Rwall) doses in high-dose post-prostatectomy intensity-modulated radiotherapy (IMRT). Materials and methodsFor 20 patients, referred for salvage IMRT after prostatectomy for prostate cancer, two planning CT-scans were performed: one with and one without an air-filled ERB. A planning target volume (PTV) was defined, using international guidelines. Furthermore, the Awall and Rwall were delineated. In both the scans, IMRT plans were generated with a prescribed dose of 70Gy. The mean dose (Dmean), maximum dose, minimum dose, and volumes exposed to doses ranging from ⩾20 to ⩾70Gy (V20–V70) to the Awall and Rwall were calculated. Finally, inner Rwall surface areas exposed to doses ranging from ⩾20 to ⩾70Gy (A20–A70) were calculated. Dose-parameters were compared between plans with and without ERB. ResultsAll Awall parameters, except V70, were significantly reduced by the ERB with an overall Dmean reduction of 6Gy. Absolute reductions in dose–volume parameters varied from 5% to 11%. Significantly reduced Rwall V30, V40, and A40 were observed with ERB, irrespective of the target volume size. ConclusionERB application significantly reduces Awall and to a lesser degree Rwall doses in high-dose post-prostatectomy IMRT.