Radiotherapy after prostatectomy: is the evidence for dose escalation out there?

Evaluating the relationship between contouring variability and modelled treatment outcome for prostate bed radiotherapy

Objectives.Contouring similarity metrics are often used in studies of inter-observer variation and automatic segmentation but do not provide an assessment of clinical impact. This study focused on post-prostatectomy radiotherapy and aimed to (1) identify if there is a relationship between variations in commonly used contouring similarity metrics and resulting dosimetry and (2) identify the variation in clinical target volume (CTV) contouring that significantly impacts dosimetry.Approach.The study retrospectively analysed CT scans of 10 patients from the TROG 08.03 RAVES trial. The CTV, rectum, and bladder were contoured independently by three experienced observers. Using these contours reference simultaneous truth and performance level estimation (STAPLE) volumes were established. Additional CTVs were generated using an atlas algorithm based on a single benchmark case with 42 manual contours. Volumetric-modulated arc therapy (VMAT) treatment plans were generated for the observer, atlas, and reference volumes. The dosimetry was evaluated using radiobiological metrics. Correlations between contouring similarity and dosimetry metrics were calculated using Spearman coefficient (Γ). To access impact of variations in planning target volume (PTV) margin, the STAPLE PTV was uniformly contracted and expanded, with plans created for each PTV volume. STAPLE dose-volume histograms (DVHs) were exported for plans generated based on the contracted/expanded volumes, and dose-volume metrics assessed.Mainresults. The study found no strong correlations between the considered similarity metrics and modelled outcomes. Moderate correlations (0.5 <Γ< 0.7) were observed for Dice similarity coefficient, Jaccard, and mean distance to agreement metrics and rectum toxicities. The observations of this study indicate a tendency for variations in CTV contraction/expansion below 5 mm to result in minor dosimetric impacts.Significance. Contouring similarity metrics must be used with caution when interpreting them as indicators of treatment plan variation. For post-prostatectomy VMAT patients, this work showed variations in contours with an expansion/contraction of less than 5 mm did not lead to notable dosimetric differences, this should be explored in a larger dataset to assess generalisability.

Prostatectomy Bed Image-guided Dose-escalated Salvage Radiotherapy (SPIDER): An International Multicenter Retrospective Study

BACKGROUND

Management of macroscopic local recurrence (MLR) after radical prostatectomy is a challenging situation with no standardized approach.

OBJECTIVE

The objective of our study was to assess the efficacy and safety of functional image-guided salvage radiotherapy (SRT) in patients with MLR in the prostate bed.

DESIGN, SETTING, AND PARTICIPANTS

In this international multicenter retrospective study across 16 European centers, eligible patients were initially treated by radical prostatectomy (RP) with or without pelvic lymph node dissection for localized or locally advanced adenocarcinoma of the prostate.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Prostate-specific antigen (PSA) measured 4 wk after RP was <0.1 ng/ml. All patients presented a biochemical relapse after RP defined by an increase in PSA level of ≥0.2 ng/ml on two successive measures. Only patients with an MLR lesion in the prostatectomy bed visualized on functional imaging (multiparametric magnetic resonance imaging, positron emission tomography/computed tomography [PET/CT] choline, or PET/CT prostate-specific membrane antigen) were eligible. Patients with lymph node, bone, or visceral dissemination at restaging imaging (CT and/or bone scintigraphy and/or magnetic resonance imaging and/or PET) were excluded. Dose escalation was defined as a dose of >66 Gy prescribed to the prostate bed or to MLR. Toxicities were classified using the Common Terminology Criteria for Adverse Events scale, version 4.03. The primary endpoint was progression-free survival (PFS). Secondary outcomes were metastasis-free survival (MPFS), biochemical progression-free survival, and overall survival. Genitourinary (GU) and gastrointestinal (GI) toxicities were analyzed.

RESULTS AND LIMITATIONS

Between January 2000 and December 2019, 310 patients received at least one dose escalation on MLR and 25 patients did not receive any dose escalation. The median PSA level before SRT was 0.63 ng/ml (interquartile range [IQR], 0.27-1.7). The median follow-up was 54 mo (IQR, 50-56). Five-year PFS and MPFS were 70% (95% confidence interval [CI]: [64; 75]) and 84% (95% CI: [78; 88]), respectively. Grade ≥2 GU and GI late toxicities were observed in 43 (12%) and 11 (3%) patients, respectively. When the prescribed dose on the MLR lesion was ≥72 Gy, an improvement in 5-yr PFS was found for patients received at least one dose escalation (73% [95% CI: 65-79]) vs 60% [95% CI: 48; 70]; p = 0.03).

CONCLUSIONS

In this contemporary study integrating functional imaging data, we found potential efficacy of SRT with dose escalation ≥72 Gy for patients with MLR in the prostate bed and with an acceptable toxicity profile. Prospective data exploring this MLR dose escalation strategy are awaited.

PATIENT SUMMARY

In this report, we looked at the outcomes from salvage radiotherapy for prostate cancer and macroscopic relapse in a large European population. We found that outcomes varied with prostate-specific antigen at relapse, Gleason score, and dose escalation. We found potential efficacy of salvage radiotherapy with dose escalation for macroscopic relapse in the prostate bed, with an acceptable toxicity profile.

Post-Operative Radiotherapy in Prostate Cancer: Is It Time for a Belt and Braces Approach?

Approximately 30% of patients treated with radical prostatectomy (RP) for prostate cancers experience biochemical recurrence (BCR). Post-operative radiation therapy (RT) can be either offered immediately after the surgery in case of aggressive pathological features or proposed early if BCR occurs. Until recently, little data were available regarding the optimal RT timing, protocol, volumes to treat, and the benefit of adding androgen deprivation therapies to post-operative RT. In this review, we aim to pragmatically discuss current literature data on these points. Early salvage RT appears to be the optimal post-operative approach, improving oncological outcomes especially with low prostate-specific antigen (PSA) levels, as well as sparing several unnecessary adjuvant treatments. The standard RT dose is still 64–66 Gy to the prostate bed in conventional fractionation, but hypofractionation protocols are emerging pending on late toxicity data. Several scientific societies have published contouring atlases, even though they are heterogeneous and deserve future consensus. During salvage RT, the inclusion of pelvic lymph nodes is also controversial, but preliminary data show a possible benefit for PSA > 0.34 ng/ml at the cost of increased hematological side effects. Concomitant ADT and its duration are also discussed, possibly advantageous (at least in terms of metastasis-free survival) for PSA rates over 0.6 ng/ml, taking into account life expectancy and cardiovascular comorbidities. Intensified regimens, for instance, with new-generation hormone therapies, could further improve outcomes in carefully selected patients. Finally, recent advances in molecular imaging, as well as upcoming breakthroughs in genomics and artificial intelligence tools, could soon reshuffle the cards of the current therapeutic strategy.

Salvage therapy for prostate cancer after radical prostatectomy

More than 40% of men with intermediate-risk or high-risk prostate cancer will experience a biochemical recurrence after radical prostatectomy. Clinical guidelines for the management of these patients largely focus on the use of salvage radiotherapy with or without systemic therapy. However, not all patients with biochemical recurrence will go on to develop metastases or die from their disease. The optimal pre-salvage therapy investigational workup for patients who experience biochemical recurrence should, therefore, include novel techniques such as PET imaging and genomic analysis of radical prostatectomy specimen tissue, as well as consideration of more traditional clinical variables such as PSA value, PSA kinetics, Gleason score and pathological stage of disease. In patients without metastatic disease, the only known curative intervention is salvage radiotherapy but, given the therapeutic burden of this treatment, importance must be placed on accurate timing of treatment, radiation dose, fractionation and field size. Systemic therapy also has a role in the salvage setting, both concurrently with radiotherapy and as salvage monotherapy.

Postoperative radiotherapy in prostate cancer: Dose and volumes

Approximately thirty percent of patients experience biochemical recurrence after radical prostatectomy for prostate cancer. Early salvage radiotherapy has recently become a standard of care in this setting. The purpose of this review is first to summarize current knowledge in terms of dose to the prostate bed in light of the recent SAKK 09/10 randomized phase III trial results. The evidence on moderate hypofractionation will also be discussed whereas extreme hypofractionation remains highly investigational. Regarding target volumes, several different guidelines have been published to address the need for standardization of postoperative target delineation. The recent GFRU (Groupe Francophone de Radiothérapie Urologique) recommendations could represent an international consensus.

Salvage-Radiation Therapy and Regional Hyperthermia for Biochemically Recurrent Prostate Cancer after Radical Prostatectomy (Results of the Planned Interim Analysis)

Simple Summary

Several efforts like dose-escalated salvage radiation therapy and the use of androgen deprivation therapy aimed to improve the postoperative treatment in patients with biochemical recurrence of prostate cancer after prostatectomy. However, the oncological outcome is still not satisfactory. Hyperthermia is well-known to improve the efficacy of radiation therapy, whereas only limited data for postoperative therapy in prostate cancer are available. Thus, we conducted a prospective multicenter non-randomized Phase-II-Trial (HTProstate) investigating the implementation of combined salvage radiation therapy and regional hyperthermia in case of biochemical recurrence after prostatectomy with the aim to evaluate the safety, feasibility, and oncological outcome of this approach. The results of our planned interim analysis (n = 50) met the criteria of safety (only one patient with acute grade 3 hyperthermia-specific toxicity), showed feasibility of planned radiation and hyperthermia therapy, no significant changes in quality of life and promising short-term prostate-specific antigen response. Late toxicity and robust oncological outcome data will be reported after completion of the trial.

Abstract

Efforts to improve the outcome of prostate cancer (PC) patients after radical prostatectomy (RP) include adjuvant or salvage radiation therapy (SRT), but still up to 50% of patients develop a disease progression after radiotherapy (RT). Regional hyperthermia (HT) is well-known to improve tumor sensitivity to RT in several entities. Here we report on a planned interim analysis of tolerability and feasibility after recruitment of the first 50 patients of a trial combining SRT and HT. We conducted a prospective multicenter non-randomized Phase-II-Trial (HTProstate-NCT04159051) investigating the implementation of combined moderate-dose escalated SRT (70 Gy in 35 fractions) and locoregional deep HT (7–10 HT sessions). The primary endpoints were the rate of acute genitourinary (GU), gastrointestinal (GI), and HT-related toxicities, completed HT sessions (≥7), and SRT applications per protocol (≥95% of patients). The two-step design included a planned interim analysis for acute GU-, GI- and HT-specific toxicities to ensure patients’ safety. Between November 2016 and December 2019, 52 patients entered into the trial. After 50 patients completed therapy and three months of follow-up, we performed the planned interim analysis. 10% of patients developed acute grade 2 GU and 4% grade 2 GI toxicities. No grade ≥3 GU or GI toxicities occurred. HT-specific symptoms grade 2 and 3 were observed in 4% and 2% of all patients. Thus, the pre-specified criteria for safety and continuation of recruitment were met. Moreover, ≥7 HT treatments were applicable, indicating the combination of SRT + HT to be feasible. Evaluation of early QoL showed no significant changes. With its observed low rate of GU and GI toxicities, moderate and manageable rates of HT-specific symptoms, and good feasibility, the combined SRT + HT seems to be a promising treatment approach for biochemical recurrence after RP in PC patients.

Predictors of 2-Year Incidence of Patient-Reported Urinary Incontinence After Post-prostatectomy Radiotherapy: Evidence of Dose and Fractionation Effects

Objective: To investigate predictors of patient-reported urinary incontinence (PRUI) in the first 2 years after post-prostatectomy radiotherapy (PORT) with particular emphasis on possible dose-effect relationships.

Patients and Methods: Two-hundred-thirteen patients, whose clinical and dosimetric data were prospectively collected within a registered multi-institutional cohort study, underwent PORT with adjuvant (n = 106) or salvage (n = 107) intent with conventional (n = 123, prescribed dose to the prostatic bed: 66.6–79.8Gy in 1.8–2.0Gy/fr) or moderately hypo- (n = 90, 65.8–76.8Gy in 2.1–2.7Gy/fr) fractionation during the period 2011–2017. PRUI was evaluated through the ICIQ-SF questionnaire filled in at baseline and every 6 months thereafter. The analysis focused on three ICIQ-based clinically relevant endpoints: (a) very frequent leakage (FREQUENCY, ICIQ3 score >3), (b) moderate to severe amount of urine loss (AMOUNT, ICIQ4>2) (c) objective severe symptoms (OBJECTIVE, ICIQ3+4>5). Predictors of the incidence within 2 years for the three endpoints were investigated focusing only on patients without endpoint symptoms at baseline. A uni-variable logistic regression analysis was performed in order to determine the best dose metrics describing PRUI risk in terms of 2-Gy equivalent dose (EQD2) calculated with different α/β values reported in the literature (0.8, 3, 5Gy), and to identify the most significant clinical variables. Variables showing p < 0.20 at uni-variable analysis were entered into a backward stepwise multi-variable logistic regression analysis. Lastly, the goodness of fit and model calibration were evaluated and internally validated.

Results: Patients without symptoms at baseline experienced (a), (b), and/or (c) within 2 years in 41/130 (32%), 40/192 (21%), and 41/129 (32%) of the cases, respectively. EQD2 for α/β = 0.8Gy was the best dose metric associated with PRUI. Multi-variable analysis identified baseline incontinence levels as the strongest predictor for all endpoints (p < 0.006). Both FREQUENCY and OBJECTIVE were significantly influenced also by EQD2(α/β = 0.8Gy). The goodness of fit was excellent, as was the calibration; internal calibration confirmed apparent performance.

Conclusion: Baseline mild urinary incontinence symptoms strongly modulate the 2-year risk of PRUI. In addition, FREQUENCY is characterized by a marked dose-effect relationship also influencing the trend of OBJECTIVE, with results more reliable than AMOUNT as an objective index. A strong impact of fractionation on severe PRUI after post-prostatectomy radiotherapy also emerged.

18F-choline PET/CT driven salvage radiotherapy in prostate cancer patients: up-date analysis with 5-year median follow-up

PURPOSE

Salvage radiotherapy is generally considered as the standard treatment for biochemical relapse after surgery. Best results have been obtained with a PSA value < 0.5 ng/ml at relapse, while 60-66 Gy is deemed as standard total dose. Modern imaging, as dynamic-18F-choline PET/CT may identify site of recurrence, allowing dose escalation to a biological target volume.

METHODS

Hundred and fifty patients showed a local relapse at dynamic-18F-choline PET/CT at time of biochemical recurrence. High-dose salvage radiotherapy was delivered up to total dose of 80 Gy to 18F-choline PET/CT positive area. Toxicity and relapse-free survival were recorded.

RESULTS

Median PSA value at the beginning of salvage radiotherapy was 0.47 ng/ml (range 0.2-17.5 ng/ml). One-hundred and thirty nine patients (93%) completed salvage radiotherapy without interruptions. Acute gastrointestinal grade ≥ 2 toxicity was recorded in 13 patients (9%), acute genitourinary grade ≥ 2 toxicity in 2 patients (1.4%). One patient (0.7%) experienced late gastrointestinal grade 4 toxicity and 2 patients (1.4%) late acute genitourinary grade 3 toxicity. With a median follow-up of 63.5 months, 5 and 7-years relapse-free survival were 70% and 60.7%, respectively.

CONCLUSION

With a median follow-up of 5 years the present study confirms that high-dose salvage radiotherapy to a biological target volume is feasible, with low rate of late toxicity and promising activity.

Clinical Outcomes of Postoperative Radiotherapy Following Radical Prostatectomy in Patients with Localized Prostate Cancer: A Multicenter Retrospective Study (KROG 18-01) of a Korean Population

PURPOSE

The purpose of this study was to investigate the clinical outcomes of postoperative radiotherapy (PORT) patients who underwent radical prostatectomy for localized prostate cancer.

Materials and Methods

Localized prostate cancer patients who received PORT after radical prostatectomy between 2001 and 2012 were identified retrospectively in a multi-institutional database. In total, 1,117 patients in 19 institutions were included. Biochemical failure after PORT was defined as prostate-specific antigen (PSA) ≥ nadir+2 after PORT or initiation of androgen deprivation therapy (ADT) for increasing PSA regardless of its value.

RESULTS

Ten-year biochemical failure-free survival, clinical failure-free survival, distant metastasisfree survival, overall survival (OS), and cause-specific survival were 60.5%, 76.2%, 84.4%, 91.1%, and 96.6%, respectively, at a median of 84 months after PORT. Pre-PORT PSA ≤ 0.5 ng/ml and Gleason's score ≤ 7 predicted favorable clinical outcomes, with 10-year OS rates of 92.5% and 94.1%, respectively. The 10-year OS rate was 82.7% for patients with a PSA > 1.0 ng/mL and 86.0% for patients with a Gleason score of 8-10. The addition of longterm ADT (≥ 12 months) to PORT improved OS, particularly in those with a Gleason score of 8-10 or ≥ T3b.

CONCLUSION

Clinical outcomes of PORT in a Korean prostate cancer population were very similar to those in Western countries. Lower Gleason score and serum PSA level at the time of PORT were significantly associated with favorable outcomes. Addition of long-term ADT (≥ 12 months) to PORT should be considered, particularly in unfavorable risk patients with Gleason scores of 8-10 or ≥ T3b.

Postoperative elective pelvic nodal irradiation compared to prostate bed irradiation in locally advanced prostate cancer - a retrospective analysis of dose-escalated patients

Background

It is uncertain if whole-pelvic irradiation (WPRT) in addition to dose-escalated prostate bed irradiation (PBRT) improves biochemical progression-free survival (bPFS) after prostatectomy for locally advanced tumors. This study was initiated to analyze if WPRT is associated with bPFS in a patient cohort with dose-escalated (> 70 Gy) PBRT.

Methods

Patients with locally advanced, node-negative prostate carcinoma who had PBRT with or without WPRT after prostatectomy between 2009 and 2017 were retrospectively analyzed. A simultaneous integrated boost with equivalent-doses-in-2-Gy-fractions (EQD-2) of 79.29 Gy or 71.43 Gy to the prostate bed was applied in patients with margin-positive (or detectable) and margin-negative/undetectable tumors, respectively. WPRT (44 Gy) was offered to patients at an increased risk of lymph node metastases.

Results

Forty-three patients with PBRT/WPRT and 77 with PBRT-only were identified. Baseline imbalances included shorter surgery-radiotherapy intervals (S-RT-Intervals) and fewer resected lymph nodes in the WPRT group. WPRT was significantly associated with better bPFS in univariate (p = 0.032) and multivariate models (HR = 0.484, p = 0.015). Subgroup analysis indicated a benefit of WPRT (p = 0.029) in patients treated with rising PSA values who mostly had negative margins (74.1%); WPRT was not associated with a longer bPFS in the postoperative setting with almost exclusively positive margins (96.8%).

Conclusion

We observed a longer bPFS after WPRT compared to PBRT in patients with locally advanced prostate carcinoma who underwent dose-escalated radiotherapy. In subset analyses, the association was only observed in patients with rising PSA values but not in patients with non-salvage postoperative radiotherapy for positive margins.

Electronic supplementary material

The online version of this article (10.1186/s13014-019-1301-5) contains supplementary material, which is available to authorized users.

Use of high and very high dose radiotherapy after radical prostatectomy for prostate cancer in the United States

BACKGROUND

The cost-benefit tradeoff of radiation dose-intensification for prostate cancer in the post-prostatectomy setting is difficult to predict and is ideally studied in randomized trials. The purpose of this study was to assess the use of dose-escalated post-operative radiation (PORT) for prostate cancer in the United States, during a period in which there were no published level 1 studies on dose-escalation.

METHODS

We performed analyses on pT2-3, N0, M0 prostate cancer patients who received PORT after an R0-1 resection within the National Cancer Data Base (NCDB), 2003-2012. We classified patients according to the use of high dose (>66.60 cGy) and very high dose (>70.20 cGy) radiation. We used regression analysis to assess the association of year of treatment with use of high and very high dose PORT. To demonstrate the potential of a registry-based network like the NCDB to prospectively monitor changes in radiation dosing patterns, we determined the year in which a significant change in dose could have been first detected had dose been actively monitored.

RESULTS

Between 2003 and 2012, the use of high dose PORT increased from 29.9% CI (26.7-33.1) to 63.5% CI (60.6-66.5) and very high dose PORT from 4.5% CI (3.1-5.9) to 10.8% CI (8.9-12.6) (adjusted p < 0.01, for both trends). Patients diagnosed at community centers were less likely to be treated with high dose PORT compared to those at academic or comprehensive centers (p < 0.01 for both comparisons). Had the NCDB network been prospectively monitoring PORT dose, significant increases in dose would have been detected as early as 2004 and after every year of the study period.

CONCLUSIONS

The use of both high dose and very high dose PORT increased two-fold from 2003 to 2012 in the absence of randomized studies. This change in practice may be exposing patients to excess toxicity without cancer control benefits. Monitoring dosing patterns using cancer registries is feasible.

Prostate-specific antigen after salvage radiotherapy for postprostatectomy biochemical recurrence predicts long-term outcome including overall survival

BACKGROUND

For patients with recurrent prostate cancer after radical prostatectomy (RP), salvage radiotherapy (SRT) is a second chance of cure. However, depending on risk factors, 40-70% of the patients experience further progression. With a focus on the pre- and post-SRT serum level of the prostate-specific antigen (PSA), we assessed the determinants of the long-term outcome after SRT.

PATIENT AND METHODS

Between 1997 and 2011, 464 patients received 3D-conformal SRT with median 66.6 Gy. The median PSA level before SRT was 0.31 ng/ml. In our retrospective analysis, post-SRT progression was defined as either a rising PSA >0.2 ng/ml above the nadir, or the application of anti-androgens or clinical recurrence. A PSA <0.1 ng/ml was termed undetectable. We analyzed the data with the Kaplan-Meier method (Logrank test) and multivariable Cox regression.

RESULTS

The median follow-up was 5.9 years. Overall, 178 patients had recurrence, 13 developed distant metastases and 30 died. Univariate, a pre-RP PSA <10 ng/ml, pathological stage pT <3, Gleason score <8, positive surgical margins, a pre-SRT PSA <0.2 ng/ml and a post-SRT PSA nadir <0.1 ng/ml correlated with fewer and later second recurrences. In a multivariable Cox model, pT, Gleason score, margin status and pre-SRT PSA were significant covariates of progression. If the post-SRT PSA response was included in the regression analysis, then a nadir ≥0.1 ng/ml was the strongest risk factor. Initiating SRT at a PSA <0.2 ng/ml correlated with a post-SRT PSA <0.1 ng/ml. Men who achieved an undetectable post-SRT PSA nadir also had lower rates of metastases and a better overall survival. However, there were too few events for Cox regression analysis of these two endpoints.

CONCLUSIONS

Early SRT at a PSA <0.2 ng/ml correlates with re-achieving an undetectable PSA, which predicts improved freedom from progression and metastases and better overall survival.

Postoperative Radiotherapy in Prostate Cancer: Acquired Certainties and Still Open Issues. A Review of Recent Literature

It is recognized that radiation therapy can eradicate microscopic tumor disease, even in postoperative prostate cancer patients, when extracapsular extension, positive surgical margins or increased prostate-specific antigen is found in surgical specimens. This review of recent literature analyzes and discusses acquired certainties and still open questions regarding type, timing, doses, techniques, toxicities, and associated hormonal therapies of radiotherapy prescribed after radical prostatectomy. Free full text available at www.tumorionline.it

Results of Dose-adapted Salvage Radiotherapy After Radical Prostatectomy Based on an Endorectal MRI Target Definition Model

OBJECTIVES

To assess the outcome of patients treated with a dose-adapted salvage radiotherapy (SRT) protocol based on an endorectal magnetic resonance imaging (erMRI) failure definition model after radical prostatectomy (RP).

METHODS

We report on 171 relapsing patients after RP who had undergone an erMRI before SRT. 64 Gy were prescribed to the prostatic bed with, in addition, a boost of 10 Gy to the suspected local relapse as detected on erMRI in 131 patients (76.6%).

RESULTS

The 3-year biochemical relapse-free survival (bRFS), local relapse-free survival, distant metastasis-free survival, cancer-specific survival, and overall survival were 64.2±4.3%, 100%, 85.2±3.2%, 100%, and 99.1±0.9%, respectively. A PSA value >1 ng/mL before salvage (P=0.006) and an absence of biochemical progression during RT (P=0.001) were both independently correlated with bRFS on multivariate analysis. No significant difference in 3-year bRFS was observed between the boost and no-boost groups (68.4±4.6% vs. 49.7±10%, P=0.251).

CONCLUSIONS

A PSA value >1 ng/mL before salvage and a biochemical progression during RT were both independently correlated with worse bRFS after SRT. By using erMRI to select patients who are most likely expected to benefit from dose-escalated SRT protocols, this dose-adapted SRT approach was associated with good biochemical control and outcome, serving as a hypothesis-generating basis for further prospective trials aimed at improving the therapeutic ratio in the salvage setting.

Patterns of Postprostatectomy Adjuvant Radiotherapy Techniques for Nonmetastatic Prostate Cancer in a Large National Cohort

PURPOSE

To analyze the contemporary patterns of care regarding adjuvant radiotherapy (RT) techniques for patients with pT3/4 disease or positive margins after prostatectomy.

PATIENTS AND METHODS

Men who were diagnosed with nonmetastatic prostate cancer and underwent prostatectomy between 2004 and 2012 were abstracted from the National Cancer Data Base. Only those with pT3-4Nx-0M0 or pT2cNx-0M0 with positive margins were included. We identified patients receiving RT to the pelvis to a dose between 5940 and 7560 cGy. Delivery of hormone therapy was also identified. Descriptive statistics were used to determine adjuvant RT use as well as patterns of care regarding RT dose and hormone use; data were compared by Pearson's chi-square test.

RESULTS

A total of 133,874 men were included in this study, of whom 12,073 (9.0%) received adjuvant RT. Of those receiving adjuvant RT, 4011 (33.2%) also received hormone therapy. There was a trend toward more frequent use of higher RT doses over time. RT doses of ≥ 7000 cGy were provided 21.4% of the time in 2004-2006 and increased over time to 38.9% by 2010-2012 (P < .001). There was also a rapid increase in the use of intensity-modulated radiotherapy from 20.7% of patients in 2004 to 69.2% in 2012.

CONCLUSION

Most men (91.0%) with pT3/T4 or pT2 disease with positive margins do not receive adjuvant RT. Use of intensity-modulated radiotherapy and RT dose escalation increased over time and are now used routinely. Hormone therapy is used in about one third of patients who are receiving RT, and its use has remained relatively stable over time.

Analysis of prostate bed motion using an endorectal balloon and cone beam computed tomography during postprostatectomy radiotherapy

Background

The authors conducted this prospective study to analyze the amount of interfractional prostate bed motion (PBM) and quantify its components with the use of an endorectal balloon (ERB).

Methods

A total of 1,348 cone beam computed tomography images from 46 patients who underwent postprostatectomy radiotherapy were analyzed. For the pilot image, electronic portal imaging, guided by skin marks was performed to ensure proper positioning and inflation of the ERB. Then, for bone matching, manual or automatic registration of the planning and each cone beam computed tomography was performed, based on the bony anatomy of the pelvis. Shifts (bony misalignment [BM]) in three directions were recorded at each treatment session. For prostate bed matching, manual matching was conducted based on the anterior rectal wall and the shift (PBM) was recorded. Total setup error was defined as the shift from the skin mark to the prostate bed matching, based on anterior rectal wall stretched by the ERB. PBM was defined as the difference between the total setup error and BM.

Results

Systematic errors for the total setup error were 1.0, 1.3, and 1.0 mm in the right–left, anterior–posterior, and superior–inferior directions, with random errors of 1.9, 2.4, and 1.9 mm, respectively. Systematic errors were 1.6, 1.6, and 0.3 mm for BM and 0.8, 1.1, and 0.9 mm for PBM, with random errors of 2.4, 2.5, and 1.1 mm for BM and 1.8, 2.2, and 1.9 mm for PBM.

Conclusion

The BM was the main component of the total setup error, suggesting that interfractional PBM was well controlled by the ERB device. Planning target volume margins of <5 mm were needed to include 95% of the interfractional variations when using an ERB.

Assessment of radiobiological metrics applied to patient-specific QA process of VMAT prostate treatments

VMAT is a powerful technique to deliver hypofractionated prostate treatments. The lack of correlations between usual 2D pretreatment QA results and the clinical impact of possible mistakes has allowed the development of 3D verification systems. Dose determination on patient anatomy has provided clinical predictive capability to patient-specific QA process. Dose-volume metrics, as evaluation criteria, should be replaced or complemented by radiobiological indices. These metrics can be incorporated into individualized QA extracting the information for response parameters (gEUD, TCP, NTCP) from DVHs. The aim of this study is to assess the role of two 3D verification systems dealing with radiobiological metrics applied to a prostate VMAT QA program. Radiobiological calculations were performed for AAPM TG-166 test cases. Maximum differences were 9.3% for gEUD, -1.3% for TCP, and 5.3% for NTCP calculations. Gamma tests and DVH-based comparisons were carried out for both systems in order to assess their performance in 3D dose determination for prostate treatments (high-, intermediate-, and low-risk, as well as prostate bed patients). Mean gamma passing rates for all structures were bet-ter than 92.0% and 99.1% for both 2%/2 mm and 3%/3 mm criteria. Maximum discrepancies were (2.4% ± 0.8%) and (6.2% ± 1.3%) for targets and normal tis-sues, respectively. Values for gEUD, TCP, and NTCP were extracted from TPS and compared to the results obtained with the two systems. Three models were used for TCP calculations (Poisson, sigmoidal, and Niemierko) and two models for NTCP determinations (LKB and Niemierko). The maximum mean difference for gEUD calculations was (4.7% ± 1.3%); for TCP, the maximum discrepancy was (-2.4% ± 1.1%); and NTCP comparisons led to a maximum deviation of (1.5% ± 0.5%). The potential usefulness of biological metrics in patient-specific QA has been explored. Both systems have been successfully assessed as potential tools for evaluating the clinical outcome of a radiotherapy treatment in the scope of pretreatment QA.

Role of Dose Intensification for Salvage Radiation Therapy after Radical Prostatectomy

For primary radiation therapy (RT) of prostate cancer, dose intensification is established as standard of care. Less is known on the role of dose intensification in the postprostatectomy setting for salvage RT. Thus, we aimed to identify and summarize the existing literature. In retrospective analyses, dose-intensified salvage RT showed a superior biochemical control compared to standard dose salvage radiation with favorable acute and late gastrointestinal and genitourinary toxicity rates, especially when modern radiation techniques such as intensity modulated RT were applied. We identified one randomized phase III trial addressing the potential benefits of dose-intensified salvage RT (SAKK 09/10). Recently, acute gastrointestinal and genitourinary toxicities and early quality of life data of this trial were reported, and no significant difference in acute toxicities between both treatment arms were found; however, a significant worsening of genitourinary quality of life was noted in the dose-intensified treatment arm. Whereas dose-intensified salvage RT appears to be feasible and well tolerated, the improved biochemical control rates using dose intensified RT as suggested by retrospective analyses have yet to be validated by prospective trials.

Value of bimodal (18)F-choline-PET/MRI and trimodal (18)F-choline-PET/MRI/TRUS for the assessment of prostate cancer recurrence after radiation therapy and radical prostatectomy

Between 27% and 53% of all patients who undergo radical prostatectomy (RP) or radiation therapy (RT) as the first-line treatment of prostate cancer (PCa) develop a biochemical recurrence. Imaging plays a pivotal role in restaging by helping to distinguish between local relapse and metastatic disease (i.e., lymph-node and skeletal metastases). At present, the most promising tools for assessing PCa patients with biochemical recurrence are multiparametric magnetic resonance imaging (mpMRI) and positron emission tomography (PET)/computed tomography (CT) with radio-labeled choline derivatives. The main advantage of mpMRI is its high diagnostic accuracy in detecting local recurrence, while choline-PET/CT is able to identify lymph-node metastases when they are not suspicious on morphological imaging. The most recent advances in the field of fusion imaging have shown that multimodal co-registration, synchronized navigation, and combined interpretation are more valuable than the individual; separate assessment offered by different diagnostic techniques. The objective of the present essay was to describe the value of bimodal choline-PET/mpMRI fusion imaging and trimodal choline-PET/mpMRI/transrectal ultrasound (TRUS) in the assessment of PCa recurrence after RP and RT. Bimodal choline-PET/mpMRI fusion imaging allows morphological, functional, and metabolic information to be combined, thereby overcoming the limitations of each separate imaging modality. In addition, trimodal real-time choline-PET/mpMRI/TRUS fusion imaging may be useful for the planning and real-time guidance of biopsy procedures in order to obtain histological confirmation of the local recurrence.

Management of prostate cancer patients following radiation therapy after radical surgery referred from urology to radiation oncology departments in Spain

PURPOSE

To define usual clinical management of prostate cancer (PCa) patients following postoperative radiation therapy (RT) (adjuvant or salvage) and its evolution over time in radiation oncology (RO) departments in Spain.

METHODS

An epidemiological, cross-sectional, multicentre study was conducted. 567 PCa patients that had undergone radical prostatectomy (RP) and received postoperative RT between February and December of both 2006 and 2011 participated in the study. In patients from 2006, health-related quality of life (HRQoL) was assessed using the EPIC questionnaire. Investigators completed a specific survey on two clinical cases of adjuvant and salvage RT.

RESULTS

70.6 % of patients received salvage RT versus 29.4 % who received adjuvant RT; no significant differences were found in terms of frequency for each procedure between both the years. Regarding the survey, a positive surgical margin was the main criteria used in adjuvant RT decision making. In terms of salvage RT scenario, 85.7 % of the investigators stated that adjuvant RT should have been offered instead, 81.4 % of the investigators agreed on a PSA score >0.2 ng/mL as the main criteria for identifying biochemical recurrence after RP, and 67.4 % of investigators did not consider any PSA score for ruling out salvage RT treatment.

CONCLUSIONS

Most patients are referred to RO departments to receive salvage RT. Despite the publication of three IA evidence level randomized clinical trials, the patterns for using adjuvant and salvage RT did not change from 2006 to 2011, although patients' profile did. A consensus regarding postoperative RT indications should be reached in order to correct this controversial situation.

Testing the Assessment of New Radiation Oncology Technology and Treatments framework using the evaluation of post-prostatectomy radiotherapy techniques

INTRODUCTION

We tested the ability of the Assessment of New Radiation Oncology Technology and Treatments framework to determine the clinical efficacy and safety of intensity-modulated radiation therapy (IMRT) compared with 3-dimensional radiation therapy (3DCRT) for post-prostatectomy radiation therapy (PPRT) to support its timely health economic evaluation.

METHODS

Treatment plans produced using FROGG guidelines provided dosimetry parameters for both techniques at 64 Gy and 70 Gy and were also used to model early and late outcome probabilities. Clinical parameters were derived from early toxicity and quality of life patient data, systematic literature review and expert opinion. Dosimetry parameters were correlated with the measures of clinical efficacy and safety.

RESULTS

Data from two patient cohorts (29 and 27 respectively) were collected within the project timeframe, providing evidence for acute toxicity and quality of life, and dosimetric comparisons. Relative rates of tumour control probability (TCP) and normal tissue control probability (NTCP) modelling were readily derived from the planning exercise and demonstrated advantages in uncomplicated TCP for IMRT over 3DCRT, predominantly due to normal tissue sparing. The safety of IMRT delivery was demonstrated with TCP uncompromised by IMRT protocol violations, which achieved rectal sparing only by reducing minimum target dose and coverage.

CONCLUSION

Sources of desk-top and patient-based evidence were successfully used to demonstrate potential improved clinical efficacy and safety of applying dose escalation using IMRT instead of 3DCRT in PPRT.

Impact of changing rectal dose volume parameters over time on late rectal and urinary toxicity after high-dose intensity-modulated radiotherapy for prostate cancer: A 10-years single centre experience

BACKGROUND

External beam radiotherapy is an excellent treatment for patients with prostate cancer (PC). Assessing long-term radiotherapy-induced toxicity is important. We evaluated the impact of implementing different rectal dose volume constraints (DVC) on late rectal and urinary toxicity.

MATERIAL AND METHODS

Six hundred and thirty-seven PC patients were treated with high-dose intensity-modulated radiotherapy (IMRT) in the primary (median dose of 78 Gy to the prostate) or postoperative setting [median dose of 74 (adjuvant) and 76 Gy (salvage) to the prostatic bed]. Three groups were defined according to different DVC applied over time. The incidence of late rectal and urinary toxicity was evaluated. Three-year actuarial risk estimations of grade 2-3 rectal and urinary toxicity were calculated (Kaplan-Meier statistics).

RESULTS

Median follow-up was five years. Overall, the incidence of late grade 3 and 2 rectal toxicity was 1% and 11%. The calculated three-year actuarial risk of developing late grade≥2 rectal toxicity decreased from 16% to 7% and 5% for patients in Group 1, Group 2 and Group 3, respectively (p<0.001). Respectively, 17 (4%) and 98 (24%) patients developed grade 3 and 2 late urinary toxicity in the primary setting. In the postoperative setting, 15 (6%) and 62 (26%) patients developed grade 3 and 2 urinary toxicity, respectively. The three-year actuarial risk of developing late≥grade 2 urinary toxicity in primary- and postoperative-treated patients was 22% and 23%, respectively. This was not significantly different between the three groups.

CONCLUSION

The majority of patients developed no or only moderate rectal toxicity after high-dose IMRT for PC. Implementing different rectal DVC resulted in a significant decrease of late rectal toxicity without affecting urinary toxicity.

Radiation therapy after radical prostatectomy for prostate cancer: evaluation of complications and influence of radiation timing on outcomes in a large, population-based cohort

Purpose

To evaluate the influence of timing of salvage and adjuvant radiation therapy on outcomes after prostatectomy for prostate cancer.

Methods

Using the Surveillance, Epidemiology, and End Results-Medicare linked database, we identified prostate cancer patients diagnosed during 1995–2007 who had one or more adverse pathological features after prostatectomy. The final cohort of 6,137 eligible patients included men who received prostatectomy alone (n = 4,509) or with adjuvant (n = 894) or salvage (n = 734) radiation therapy. Primary outcomes were genitourinary, gastrointestinal, and erectile dysfunction events and survival after treatment(s).

Results

Radiation therapy after prostatectomy was associated with higher rates of gastrointestinal and genitourinary events, but not erectile dysfunction. In adjusted models, earlier treatment with adjuvant radiation therapy was not associated with increased rates of genitourinary or erectile dysfunction events compared to delayed salvage radiation therapy. Early adjuvant radiation therapy was associated with lower rates of gastrointestinal events that salvage radiation therapy, with hazard ratios of 0.80 (95% CI, 0.67–0.95) for procedure-defined and 0.70 (95% CI, 0.59, 0.83) for diagnosis-defined events. There was no significant difference between ART and non-ART groups (SRT or RP alone) for overall survival (HR = 1.13 95% CI = (0.96, 1.34) p = 0.148).

Conclusions

Radiation therapy after prostatectomy is associated with increased rates of gastrointestinal and genitourinary events. However, earlier radiation therapy is not associated with higher rates of gastrointestinal, genitourinary or sexual events. These findings oppose the conventional belief that delaying radiation therapy reduces the risk of radiation-related complications.

The natural course of pT2 prostate cancer with positive surgical margin: predicting biochemical recurrence

PURPOSE

To predict biochemical recurrence respecting the natural course of pT2 prostate cancer with positive surgical margin (R1) and no adjuvant/neoadjuvant therapy.

METHODS

A multicenter data analysis of 956 patients with pT2R1N0/Nx tumors was performed. Patients underwent radical prostatectomy between 1994 and 2009. No patients received neoadjuvant or adjuvant therapy. All prostate specimens were re-evaluated according to a well-defined protocol. The association of pathological and clinical features, in regard to BCR, was calculated using various statistical tests.

RESULTS

With a mean follow-up of 48 months, BCR was found in 25.4 %. In univariate analysis, multiple parameters such as tumor volume, PSA, Gleason at positive margin were significantly associated with BCR. However, in multivariate analysis, Gleason score (GS) of the prostatectomy specimen was the only significant parameter for BCR. Median time to recurrence for GS ≤ 6 was not reached; 5-year BCR-free survival was 82 %; and they were 127 months and 72 % for GS 3+4, 56 months and 54 % for GS 4 + 3, and 27 months and 32 % for GS 8-10. The retrospective approach is a limitation of our study.

CONCLUSIONS

Our study provides data on the BCR in pT2R1-PCa without adjuvant/neoadjuvant therapy and thus a rationale for an individual's risk stratification. The data support patients and physicians in estimating the individual risk and timing of BCR and thus serve to personalize the management in pT2R1-PCa.

¹⁸F-choline positron emission tomography/computed tomography-driven high-dose salvage radiation therapy in patients with biochemical progression after radical prostatectomy: feasibility study in 60 patients

PURPOSE

To retrospectively review data of a cohort of patients with biochemical progression after radical prostatectomy, treated according to a uniform institutional treatment policy, to evaluate toxicity and feasibility of high-dose salvage radiation therapy (80 Gy).

METHODS AND MATERIALS

Data on 60 patients with biochemical progression after radical prostatectomy between January 2009 and September 2011 were reviewed. The median value of prostate-specific antigen before radiation therapy was 0.9 ng/mL. All patients at time of diagnosis of biochemical recurrence underwent dynamic (18)F-choline positron emission tomography/computed tomography (PET/CT), which revealed in all cases a local recurrence. High-dose salvage radiation therapy was delivered up to total dose of 80 Gy to 18F-choline PET/CT-positive area. Toxicity was recorded according to the Common Terminology Criteria for Adverse Events, version 3.0, scale.

RESULTS

Treatment was generally well tolerated: 54 patients (90%) completed salvage radiation therapy without any interruption. Gastrointestinal grade ≥2 acute toxicity was recorded in 6 patients (10%), whereas no patient experienced a grade ≥2 genitourinary toxicity. No grade 4 acute toxicity events were recorded. Only 1 patient (1.7%) experienced a grade 2 gastrointestinal late toxicity. With a mean follow-up of 31.2 months, 46 of 60 patients (76.6%) were free of recurrence. The 3-year biochemical progression-free survival rate was 72.5%.

CONCLUSIONS

At early follow-up, (18)F-choline PET/CT-driven high-dose salvage radiation therapy seems to be feasible and well tolerated, with a low rate of toxicity.

Higher-than-expected severe (Grade 3-4) late urinary toxicity after postprostatectomy hypofractionated radiotherapy: a single-institution analysis of 1176 patients

BACKGROUND

Dose escalation and hypofractionation may have a role in postprostatectomy radiotherapy (RT), but at the risk of increasing urinary toxicity.

OBJECTIVE

To address predictors of severe (Grade ≥3) late urinary toxicities (LGUTOX3) after postoperative irradiation.

DESIGN, SETTING, AND PARTICIPANTS

A single-institution cohort of 1176 patients treated between 1993 and 2010 with adjuvant or salvage RT was analyzed. A total of 929 patients underwent conventionally fractionated (CF) RT (1.8 Gy per fraction; median dose to the prostatic bed: 70.2 Gy) with nonconformal RT (n=169), three-dimensional conformal RT (n=657), or intensity-modulated RT (n=103) technique, while 247 patients received hypofractionated helical TomoTherapy (median: 2.50 Gy per fraction) at the following doses: 117 patients at 65.8 Gy (2.35 Gy in 28 fractions), 80 patients at a median of 71.4 Gy (2.5-2.6 Gy in 28 fractions), and 50 patients at 58 Gy in 20 fractions. Total doses were converted into 2 Gy-equivalent doses (EQD2) following the linear quadratic model taking α/β=5.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Univariable and multivariable Cox regression models tested the relationship between clinicodosimetric variables and the risk of LGUTOX3 retrospectively, graded according to Common Terminology Criteria for Adverse Events v.4.0.

RESULTS AND LIMITATIONS

After a median follow-up of 98 mo, the 5-yr risk of LGUTOX3 was 6.9% and 18.1% in the CF and hypofractionated cohorts, respectively. At univariable analysis, the risk of LGUTOX3 was predicted by dose per fraction (hazard ratio [HR]: 2.96), acute Grade ≥2 toxicity (HR: 2.37), EQD2, pT4, and year of irradiation. At multivariable analyses, acute Grade ≥2 toxicity and dose per fraction independently predicted LGUTOX3 in the population, while an interaction analysis indicated a predictive role of hypertension in the hypofractionated cohort only. These findings are limited by their retrospective nature.

CONCLUSIONS

In the postprostatectomy setting, the logistic convenience of hypofractionation should be carefully balanced against the risk of severe late urinary sequelae.

PATIENT SUMMARY

This study investigated the causes of urinary adverse effects after postprostatectomy radiotherapy. Hypofractionation resulted in an increased risk of severe urinary toxicities.

A decision model to estimate the cost-effectiveness of intensity modulated radiation therapy (IMRT) compared to three dimensional conformal radiation therapy (3DCRT) in patients receiving radiotherapy to the prostate bed

BACKGROUND

Intensity modulated radiation therapy (IMRT) is a radiation therapy technology that facilitates the delivery of an improved dose distribution with less dose to surrounding critical structures. This study estimates the longer term effectiveness and cost-effectiveness of IMRT in patients post radical prostatectomy.

METHODS

A Markov decision model was developed to calculate the incremental quality adjusted life years (QALYs) and costs of IMRT compared with three dimensional conformal radiation therapy (3DCRT). Costs were estimated from the perspective of the Australian health care system.

RESULTS

IMRT was both more effective and less costly than 3DCRT over 20 years, with an additional 20 QALYs gained and over $1.1 million saved per 1000 patients treated. This result was robust to plausible levels of uncertainty.

CONCLUSIONS

IMRT was estimated to have a modest long term advantage over 3DCRT in terms of both improved effectiveness and reduced cost. This result was reliant on clinical judgement and interpretation of the existing literature, but provides quantitative guidance on the cost effectiveness of IMRT whilst long term trial evidence is awaited.

Effect on therapeutic ratio of planning a boosted radiotherapy dose to the dominant intraprostatic tumour lesion within the prostate based on multifunctional MR parameters

OBJECTIVE

To demonstrate the feasibility of an 8-Gy focal radiation boost to a dominant intraprostatic lesion (DIL), identified using multiparametric MRI (mpMRI), and to assess the potential outcome compared with a uniform 74-Gy prostate dose.

METHODS

The DIL location was predicted in 23 patients using a histopathologically verified model combining diffusion-weighted imaging, dynamic contrast-enhanced imaging, T2 maps and three-dimensional MR spectroscopic imaging. The DIL defined prior to neoadjuvant hormone downregulation was firstly registered to MRI-acquired post-hormone therapy and subsequently to CT radiotherapy scans. Intensity-modulated radiotherapy (IMRT) treatment was planned for an 8-Gy focal boost with 74-Gy dose to the remaining prostate. Areas under the dose-volume histograms (DVHs) for prostate, bladder and rectum, the tumour control probability (TCP) and normal tissue complication probabilities (NTCPs) were compared with those of the uniform 74-Gy IMRT plan.

RESULTS

Deliverable IMRT plans were feasible for all patients with identifiable DILs (20/23). Areas under the DVHs were increased for the prostate (75.1 ± 0.6 vs 72.7 ± 0.3 Gy; p < 0.001) and decreased for the rectum (38.2 ± 2.5 vs 43.5 ± 2.5 Gy; p < 0.001) and the bladder (29.1 ± 9.0 vs 36.9 ± 9.3 Gy; p < 0.001) for the boosted plan. The prostate TCP was increased (80.1 ± 1.3 vs 75.3 ± 0.9 Gy; p < 0.001) and rectal NTCP lowered (3.84 ± 3.65 vs 9.70 ± 5.68 Gy; p = 0.04) in the boosted plan. The bladder NTCP was negligible for both plans.

CONCLUSION

Delivery of a focal boost to an mpMRI-defined DIL is feasible, and significant increases in TCP and therapeutic ratio were found.

ADVANCES IN KNOWLEDGE

The delivery of a focal boost to an mpMRI-defined DIL demonstrates statistically significant increases in TCP and therapeutic ratio.

Adjuvant radiotherapy after prostatectomy for prostate cancer in Japan: a multi-institutional survey study of the JROSG

In Japan, the use of adjuvant radiotherapy after prostatectomy for prostate cancer has not increased compared with the use of salvage radiotherapy. We retrospectively evaluated the outcome of adjuvant radiotherapy together with prognostic factors of outcome in Japan. Between 2005 and 2007, a total of 87 patients were referred for adjuvant radiotherapy in 23 institutions [median age: 64 years (54-77 years), median initial prostate-specific antigen: 11.0 ng/ml (2.9-284 ng/ml), Gleason score (GS): 6, 7, 8, 9, 10 = 13.8, 35.6, 23.0, 27.6, 0%, respectively]. Rates of positive marginal status, seminal vesicle invasion (SVI) and extra-prostatic extension (EPE) were 74%, 26% and 64%, respectively. Median post-operative PSA nadir: 0.167 ng/ml (0-2.51 ng/ml). Median time from surgery to radiotherapy was 3 months (1-6 months). A total dose of ≥ 60 Gy and <65 Gy was administered to 69% of patients. The median follow-up time was 62 months. The 3- and 5-year biochemical relapse-free survival (bRFS) rates for all patients were 66.5% and 57.1%, respectively. The GS and marginal status (P = 0.019), GS and SVI (P = 0.001), marginal status and EPE (P = 0.017), type of hormonal therapy and total dose (P = 0.026) were significantly related. The 5-year bRFS rate was significantly higher in SVI-negative patients than SVI-positive patients (P = 0.001), and significantly higher in patients with post-operative PSA nadir ≤ 0.2 than in patients with post-operative PSA nadir >0.2 (P = 0.02), and tended to be more favorable after radiotherapy ≤ 3 months from surgery than >3 months from surgery (P = 0.069). Multivariate analysis identified SVI and post-operative PSA nadir as independent prognostic factors for bRFS (P = 0.001 and 0.018, respectively).

Biochemical and clinical outcomes after high-dose salvage radiotherapy as monotherapy for prostate cancer

PURPOSE

To retrospectively evaluate the role of high-dose salvage radiotherapy (SRT) alone with regard to biochemical and clinical outcomes in patients with biochemical failure (BF) after radical prostatectomy (RP).

METHODS

Between January 2003 and August 2011, 168 hormone-naïve localized prostate cancer patients received SRT alone for post-RP BF in a single institution and were retrospectively analyzed. Multivariate analysis was performed to determine the independent prognostic impact of clinical factors on biochemical and clinical outcomes [biochemical relapse-free survival (bRFS), clinical relapse-free survival (cRFS), cancer-specific survival (CSS) and overall survival (OS)].

RESULTS

Median follow-up was 54 months. Actuarial bRFS, cRFS, CSS and OS at 5 years were, respectively, 64, 86.2, 94.5 and 96.3 %. On multivariate analysis, nadir PSA (nPSA) after SRT was significantly associated with bRFS (HR 15, p = 0.001) and cRFS (HR 9, p = 0.001), while CSS was associated with RT dose (≥70 Gy; HR 1.9 p = 0.023), pre-RT PSA (<1.5 vs. ≥1.5 ng/mL; HR 1.3, p = 0.008) and age (>75 years; HR 1.2, p = 0.05). OS was significantly correlated with pre-SRT PSA (linear correlation; HR 1.1, p = 0.023) and age (<75 vs. ≥ 75 years; HR 1.1, p = 0.026).

CONCLUSIONS

Effective biochemical and clinical control rates may be safely achieved administering SRT with high doses (≥72 Gy) and using conformal techniques, especially in older patients presenting with lower pre-SRT PSA values. A lower nPSA after SRT predicts for better 5 years bRFS and cRFS rates.

Is biochemical relapse-free survival after profoundly hypofractionated radiotherapy consistent with current radiobiological models?

AIMS

The α/β ratio for prostate cancer is thought to be low and less than for the rectum, which is usually the dose-limiting organ. Hypofractionated radiotherapy should therefore improve the therapeutic ratio, increasing cure rates with less toxicity. A number of models for predicting biochemical relapse-free survival have been developed from large series of patients treated with conventional and moderately hypofractionated radiotherapy. The purpose of this study was to test these models when significant numbers of patients treated with profoundly hypofractionated radiotherapy were included.

MATERIALS AND METHODS

A systematic review of the literature with regard to hypofractionated radiotherapy for prostate cancer was conducted, focussing on data recently presented on prostate stereotactic body radiotherapy. For the work described here, we have taken published biochemical control rates for a range of moderately and profoundly fractionated schedules and plotted these together with a range of radiobiological models, which are described.

RESULTS

The data reviewed show consistency between the various radiobiological model predictions and the currently observed data.

CONCLUSION

Current radiobiological models provide accurate predictions of biochemical relapse-free survival, even when profoundly hypofractionated patients are included in the analysis.

Adjuvant radiotherapy versus wait-and-see after radical prostatectomy: 10-year follow-up of the ARO 96-02/AUO AP 09/95 trial

BACKGROUND

Local failure after radical prostatectomy (RP) is common in patients with cancer extending beyond the capsule. Three prospectively randomized trials demonstrated an advantage for adjuvant radiotherapy (ART) compared with a wait-and-see (WS) policy.

OBJECTIVE

To determine the efficiency of ART after a 10-yr follow-up in the ARO 96-02 study.

DESIGN, SETTING, AND PARTICIPANTS

After RP, 388 patients with pT3 pN0 prostate cancer (PCa) were randomized to WS or three-dimensional conformal ART with 60 Gy. The present analysis focuses on intent-to-treat patients who achieved an undetectable prostate-specific antigen after RP (ITT2 population)--that is, 159 WS plus 148 ART men.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary end point of the study was progression-free survival (PFS) (events: biochemical recurrence, clinical recurrence, or death). Outcomes were compared by log-rank test. Cox regression analysis served to identify variables influencing the course of disease.

RESULTS AND LIMITATIONS

The median follow-up was 111 mo for ART and 113 mo for WS. At 10 yr, PFS was 56% for ART and 35% for WS (p<0.0001). In pT3b and R1 patients, the rates for WS even dropped to 28% and 27%, respectively. Of all 307 ITT2 patients, 15 died from PCa, and 28 died for other or unknown reasons. Neither metastasis-free survival nor overall survival was significantly improved by ART. However, the study was underpowered for these end points. The worst late sequelae in the ART cohort were one grade 3 and three grade 2 cases of bladder toxicity and two grade 2 cases of rectum toxicity. No grade 4 events occurred.

CONCLUSIONS

Compared with WS, ART reduced the risk of (biochemical) progression with a hazard ratio of 0.51 in pT3 PCa. With only one grade 3 case of late toxicity, ART was safe.

PATIENT SUMMARY

Precautionary radiotherapy counteracts relapse after surgery for prostate cancer with specific risk factors.

Dose-adapted salvage radiotherapy after radical prostatectomy based on an erMRI target definition model: toxicity analysis

BACKGROUND

To assess treatment tolerance by patients treated with a dose-adapted salvage radiotherapy (SRT) protocol based on an multiparametric endorectal magnetic resonance imaging (erMRI) failure definition model after radical prostatectomy (RP).

MATERIAL AND METHODS

A total of 171 prostate cancer patients recurring after RP undergoing erMRI before SRT were analyzed. A median dose of 64 Gy was delivered to the prostatic bed (PB) with, in addition, a boost of 10 Gy to the suspected relapse as visualized on erMRI in 131 patients (76.6%). Genitourinary (GU) and gastrointestinal (GI) toxicities were scored using the RTOG scale.

RESULTS

Grade ≥ 3 GU and GI acute toxicity were observed in three and zero patients, respectively. The four-year grade ≥ 2 and ≥ 3 late GU and GI toxicity-free survival rates (109 patients with at least two years of follow-up) were 83.9 ± 4.7% and 87.1 ± 4.2%, and 92.1 ± 3.6% and 97.5 ± 1.7%, respectively. Boost (p = 0.048) and grade ≥ 2 acute GU toxicity (p = 0.008) were independently correlated with grade ≥ 2 late GU toxicity on multivariate analysis.

CONCLUSIONS

A dose-adapted, erMRI-based SRT approach treating the PB with a boost to the suspected local recurrence may potentially improve the therapeutic ratio by selecting patients that are most likely expected to benefit from SRT doses above 70 Gy as well as by reducing the size of the highest-dose target volume. Further prospective trials are needed to investigate the use of erMRI in SRT as well as the role of dose-adapted protocols and the best fractionation schedule.

[Prostate cancer surgical margin: review by the CCAFU (Oncology Committee of the French Association of Urology)]

OBJECTIVE

Literature showed the impact of surgical margin status on prognosis after radical prostatectomy (mostly on biochemical survival). Margin status is an easy self-evaluation of surgical practice to assess. The aim of this paper was to define what a positive surgical margin (PSM) is and how to prevent the occurrence, to precise the impact on survival and how to treat.

METHOD

A literature analysis with Pubmed has been performed to 2012, furthermore conclusions of the main congresses with selection committee and review publication have also been studied.

RESULTS

PSM is defined as "tumor cells touching the ink on the specimen edge". The most frequent reported incidence is between 15 to 20%. Margin status remains one of the major criteria to determine the need of adjuvant radiotherapy after surgery. Quality of life is not or only lightly modified by radiotherapy with the current techniques. Adjuvant radiotherapy improves biological survival but is synonymous with overtreatment in many times. Salvage radiotherapy has to be quickly performed after Prostate Specific Antigen (PSA) relapse (PSA<1 ng/mL even<0.5 ng/mL).

CONCLUSION

This literature review did not allow to suggest superiority of one surgical technique over another. In the same way, the kind of dissection i.e. bladder neck or neurovascular bundle preservation does no clearly modify PSM rate. However, it seems logical to "customize" dissection according to prostate cancer characteristics (D'Amico criteria for instance) guided with multiparametric MRI. Intrafascial dissection has to be applied only to low risk. Lastly, the debate between adjuvant or salvage radiotherapy is always ongoing.

Radiotherapy in the management of prostate cancer after radical prostatectomy

The choice of treatment options for prostate cancer patients who have undergone radical prostatectomy depends on their risk profile, which is determined by the tumor node metastasis (TNM) status, histopathologic findings, and the pre- and post-radical prostatectomy PSA characteristics. The results of large clinical studies with a 10-year follow-up or more are the backbone of predictive models for risk estimates that incorporate these criteria and also for guideline recommendations. For low-to-intermediate-risk prostate cancer patients and older patients, observation with--in case of biochemical recurrence--early salvage radiotherapy can be advised after R0 resection, thus, avoiding overtreatment. After R1 resection, adjuvant radiotherapy should be considered. Patients with two or more positive lymph nodes and/or with distant metastasis may benefit from adjuvant hormone deprivation therapy. Beyond this rough outline, detailed analysis of subgroups is still required (and ongoing) to enable individually optimized treatment.