Toxicity analysis of postoperative image-guided intensity-modulated radiotherapy for prostate cancer

10-yr Results of Moderately Hypofractionated Postoperative Radiotherapy for Prostate Cancer Focused on Treatment Related Toxicity

INTRODUCTION

To retrospectively report long term outcomes following postoperative hypofractionated radiotherapy (RT) for prostate cancer, emphasizing treatment related toxicity.

MATERIAL AND METHODS

Patients for whom adjuvant or salvage RT was indicated after prostatectomy were treated with a course of moderate hypofractionation consisting in the delivery of 62.5 Gy in 25 fractions (2.5 Gy per fraction) on the prostate bed in 5 consecutive weeks (EQD21.5 = 70 Gy) by means of 3D-CRT in most of them. Androgen deprivation therapy (ADT) was allowed at physician's discretion. Patients were evaluated for urinary and rectal complications according to the Common Terminology Criteria for Adverse Events v4 (CTCAE v.4). Overall survival (OS), biochemical recurrence free survival (bRFS), and metastasis-free survival (MFS) were estimated using the Kaplan-Meier method.

RESULTS

One hundred and ten patients with a median age of 67 years (range 51-78) were enrolled. The majority of them (82%) had adverse pathologic features only, while 31 (28%) had early biochemical relapse. Median PSA level before RT was 0.12 ng/mL (range 0-9 ng/mL). Median time from surgery was 4 months (range 1-136 months). Twenty-eight patients (25.4%) also received ADT. At a median follow up of 103 months (range 19-138 months), late Grade 3 and Grade 4 rectal toxicity were 0.9% (1 case of hematochezia) and 0.9% (1 case of fistula), respectively, while late Grade 3 GU side effects (urethral stenosis) occurred in 9 cases (8%). No late Grade 4 events were observed, respectively. Ten-year OS, b-RFS and MFS were 77.3% (95%CI: 82.1%-72.5%), 53.3% (95%CI: 59.9%-47.6%), and 76.7% (95%CI: 81.2%-72.2%), respectively.

CONCLUSION

Our study provides long term data that a shortened course of postoperative RT is as safe and effective as a long course of conventionally fractionated RT and would improve patients' convenience and significantly reduce RT department workloads.

Late genitourinary toxicity in salvage radiotherapy for prostate cancer after radical prostatectomy: impact of daily fraction doses

OBJECTIVE

To evaluate the impact of daily fraction doses on late genitourinary (GU) toxicity after salvage radiotherapy (SRT) for prostate cancer.

METHODS

This multi-institutional retrospective study included 212 patients who underwent SRT between 2008 and 2018. All patients received image-guided intensity-modulated SRT at a median dose of 67.2 Gy in 1.8-2.3 Gy/fraction. The cumulative rates of late grade ≥2 GU and gastrointestinal (GI) toxicities were compared using Gray test, stratified by the ≤2.0 Gy/fraction (n = 137) and ≥2.1 Gy/fraction groups (n = 75), followed by multivariate analyses. The total dose was represented as an equivalent dose in 2-Gy fractions (EQD2) with α/β = 3 Gy.

RESULTS

After a median follow-up of 63 months, the cumulative rates of 5-year late grade ≥2 GU and GI toxicities were 14% and 2.5%, respectively. The cumulative rates of 5-year late grade ≥2 GU toxicity in the ≥2.1 Gy/fraction and ≤2.0 Gy/fraction groups were 22% and 10%, respectively (P = .020). In the multivariate analysis, ≥2.1 Gy/fraction was still associated with an increased risk of late grade ≥2 GU toxicity (hazard ratio, 2.37; 95% confidence interval, 1.12-4.99; P = .023), while the total dose was not significant.

CONCLUSION

The present results showed that ≥2.1 Gy/fraction resulted in a higher incidence of late grade ≥2 GU toxicity in SRT.

ADVANCES IN KNOWLEDGE

The impact of fraction doses on late GU toxicity after SRT remains unknown. The results suggest that higher fraction doses may increase the risk of late GU toxicity in SRT.

Impact of radiation doses on clinical relapse of biochemically recurrent prostate cancer after prostatectomy

The relationship between radiation doses and clinical relapse in patients receiving salvage radiotherapy (SRT) for biochemical recurrence (BCR) after radical prostatectomy (RP) remains unclear. We identified 292 eligible patients treated with SRT between 2005 and 2018 at 15 institutions. Clinical relapse-free survival (cRFS) between the ≥ 66 Gy (n = 226) and < 66 Gy groups (n = 66) were compared using the Log-rank test, followed by univariate and multivariate analyses and a subgroup analysis. After a median follow-up of 73 months, 6-year biochemical relapse-free survival, cRFS, cancer-specific survival, and overall survival rates were 58, 92, 98, and 94%, respectively. Six-year cRFS rates in the ≥ 66 Gy and < 66 Gy groups were 94 and 87%, respectively (p = 0.022). The multivariate analysis revealed that Gleason score ≥ 8, seminal vesicle involvement, PSA at BCR after RP ≥ 0.5 ng/ml, and a dose < 66 Gy correlated with clinical relapse (p = 0.015, 0.012, 0.024, and 0.0018, respectively). The subgroup analysis showed the consistent benefit of a dose ≥ 66 Gy in patients across most subgroups. Doses ≥ 66 Gy were found to significantly, albeit borderline, increase the risk of late grade ≥ 2 GU toxicity compared to doses < 66 Gy (14% vs. 3.2%, p = 0.055). This large multi-institutional retrospective study demonstrated that a higher SRT dose (≥ 66 Gy) resulted in superior cRFS.

Postoperative moderately hypofractionated radiotherapy in prostate cancer: a mono-institutional propensity-score-matching analysis between adjuvant and early-salvage radiotherapy

AIM

To evaluate the impact of moderately hypofractionated postoperative radiotherapy (RT) in prostate cancer (PCa).

MATERIALS AND METHODS

The data of 304 surgically resected PCa patients were analyzed. One hundred and five patients underwent adjuvant RT (aRT), 77 early-savage RT (esRT), and 123 salvage RT (sRT). Biochemical relapse-free survival (BRFS), progression-free survival (PFS) and toxicity were analyzed. A propensity score matching (PSM) was performed to account for potential confounders between aRT and esRT groups.

RESULTS

The median follow-up was 33 months. Three-year BRFS and PFS were 82 and 85.2%, respectively, in the overall population. At the multivariate analysis, Gleason score and hormone therapy were factors independently correlated with BRFS and PFS. After PSM, there was no difference in BRFS and PFS between aRT and esRT patients. Severe toxicity was represented by grade 3 urinary incontinence (3.5%) and urgency (1%), and aRT correlated with increased any-grade acute toxicity. Severe grade 3 gastrointestinal late toxicity occurred in 1.3% of cases.

CONCLUSION

Postoperative moderately hypofractionated RT achieved acceptable disease control rate and demonstrated no increased or unexpected toxicity. Future prospective studies should evaluate the role of postoperative RT in patients with unfavorable disease characteristics.

Stereotactic or conventional radiotherapy for macroscopic prostate bed recurrence: a propensity score analysis

Purpose

To assess outcomes between salvage radiation therapy (SRT) with curative intent and stereotactic radiotherapy for macroscopic prostate recurrence (SSRT) after radical prostatectomy (RP). In order to compare these two different options, we compared their outcomes with a propensity score-based matched analysis.

Methods

Data from 185 patients in seven Italian centres treated for macroscopic prostate bed recurrence after RP were retrospectively collected. To make a comparison between the two treatment groups, propensity matching was applied to create comparable cohorts.

Results

After matching, 90 patients in the SRT and SSRT groups were selected (45 in each arm). Kaplan–Meier analysis did not show any significant differences in terms of BRFS and PFS between matched populations (p = 0.08 and p = 0.8, respectively). Multivariate models show that treatment was not associated with BRFS, neither in the whole or matched cohort, with HR of 2.15 (95%CI 0.63–7.25, p = 0.21) and 2.65 (95%CI 0.59–11.97, p = 0.21), respectively. In the matched cohort, lower rate of toxicity was confirmed for patients undergoing SSRT, with acute GI and GU adverse events reported in 4.4 versus 44.4% (p < 0.001) and 28.9 versus 46.7% (p = 0.08) of patients, and late GI and GU adverse events reported in 0 versus 13.3% (p = 0.04) and 6.7 versus 22.2% (p = 0.03) of patients, respectively.

Conclusion

Considering the favourable therapeutic ratio of this approach and the lower number of fractions needed, SSRT should be considered as an attractive alternative to conventional SRT in this setting.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11547-022-01465-w.

Postoperative or Salvage Proton Radiotherapy for Prostate Cancer After Radical Prostatectomy

Purpose

Postprostatectomy radiation improves disease control, but limited data exist regarding outcomes, toxicities, and patient-reported quality of life with proton therapy.

Method and Materials

The first 102 patients who were enrolled on an outcome tracking protocol between 2006 and 2017 and treated with double-scattered proton therapy after prostatectomy were retrospectively reviewed. Eleven (11%) received adjuvant radiation, while 91 (89%) received salvage radiation. Seventy-four received double-scattered proton therapy to the prostate bed only. Twenty-eight received a double-scattered proton therapy prostate-bed boost after prostate-bed and pelvic-node treatment. Eleven adjuvant patients received a median dose of 66.6 GyRBE (range, 66.0-70.2). Ninety-one salvage patients received a median dose of 70.2 GyRBE (range, 66.0-78.0). Forty-five patients received androgen deprivation therapy for a median 9 months (range, 1-30). Toxicities were scored using Common Terminology Criteria for Adverse Events v4.0 criteria, and patient-reported quality-of-life data were reviewed.

Results

The median follow-up was 5.5 years (range, 0.8-11.4 years). Five-year biochemical relapse-free and distant metastases-free survival rates were 72% and 91% for adjuvant patients, 57% and 97% for salvage patients, and 57% and 97% overall. Acute and late grade 3 or higher genitourinary toxicity rates were 1% and 7%. No patients had grade 3 or higher gastrointestinal toxicity. Acute and late grade 2 gastrointestinal toxicities were 5% and 2%. The mean values and SDs of the International Prostate Symptom Score, International Index of Erectile Function, and Expanded Prostate Cancer Index Composite bowel function and bother were 7.5 (SD = 5.9), 10.2 (SD = 8.3), 92.8 (SD = 11.1), and 91.2 (SD = 6.4), respectively, at baseline, and 12.1 (SD = 9.1), 10.1 (SD = 6.7), 87.3 (SD = 18), and 86.7 (SD = 13.8) at the 5-year follow-up.

Conclusion

High-dose postprostatectomy proton therapy provides effective long-term biochemical control and freedom from metastasis, with low acute and long-term gastrointestinal and genitourinary toxicity.

A comparison of side-effects and quality-of-life in patients operated on for prostate cancer with and without salvage radiation therapy

PURPOSE

The extent of late side-effects in prostate cancer patients, after radical prostatectomy (RP = reference group) and salvage radiation therapy (SRT) in a self-reporting perspective (PROM) is still under-reported. We aimed to investigate the rate and severity of side-effects and quality-of-life (QoL) according to PROM.

METHODS AND MATERIALS

A PROM survey was administered to a cohort of SRT patients matched to a reference group with median follow-up 10 years after surgery. In total, 740 patients were analyzed. To investigate the association between SRT versus reference group regarding side-effects and QoL, a Poisson regression analysis was conducted and presented as relative risk estimates (RR) together with 95% confidence intervals regarding questions related to urinary, rectal, sexual symptoms and QoL.

RESULTS

RRs ranged from of 1.7-6.5 on rectal symptoms and 1.2-1.4 for urinary symptoms. In general health, QoL and sexual function all RRs were below 1.1. With increasing age, higher RRs were seen for urinary leakage and lowered sexual function whereas longer time following irradiation showed higher RRs for rectal symptoms and rectal leakage. Limitations of this study include the cross-sectional design and lack of baseline assessment.

CONCLUSIONS

Adding SRT to RP does not seem to result in other than acceptable side-effects in the majority of men receiving SRT when taking a long follow-up time (median 10 years after surgery) into account. However, a subset of men develop severe side-effects where rectal bleeding dominates.

Detection rate, pattern of relapse and influence on therapeutic decision of PSMA PET/CT in patients affected by biochemical recurrence after radical prostatectomy, a retrospective case series

AIMS

⁶⁸Ga-Prostate-specific membrane antigen (PSMA) PET/CT is widely used in patients with biochemical recurrence (BCR) after radical prostatectomy. We collected data about patients staged with PSMA PET/CT after BCR (PSA < 1 ng/ml) in four different institutes. Impact of baseline features (Gleason score, risk classification, PSA at recurrence, PSA doubling time and time to recurrence) was explored to understand predictive factors of (PSMA) PET/CT positivity. Impact of restaging on following treatment approaches was reported.

RESULTS

92 patients were included. PSMA PET/CT detection rate was 56.5% and low-volume disease (≤ 3 non-visceral lesions) was detected in 52.2% of patients. After positive scan, 13.5% of patients still lies on observation, ADT alone was administered in 30.8% of cases, Stereotactic body RT (SBRT) alone was delivered to 44.2% of patients and 11.5% of patients underwent concomitant SBRT and ADT. Seven patients underwent conventional salvage prostate bed RT. Chi-squared test showed a higher rate of positive PSMA PET/CT for patients with Gleason score > 7 (p = 0.004) and TTR < 29.5 months (p = 0.003).

CONCLUSIONS

PSMA PET/CT showed a high detection rate. This influenced clinical management in a significant percentage of patients, allowing treatment tailoring on the basis of imaging.

Dose-volume Histogram-based Predictors for Hematuria and Rectal Hemorrhage in Patients Receiving Radiotherapy After Radical Prostatectomy

AIM

The aim of this study was to evaluate the dose-volume histogram parameters for late hematuria and rectal hemorrhage in patients receiving radiotherapy after radical prostatectomy.

PATIENTS AND METHODS

Data of 86 patients treated between January 2006 and June 2019 were retrospectively evaluated. The median radiation dose was 64 Gy in 32 fractions. Receiver operating characteristic (ROC) curves were used to identify optimal cut-off values for late adverse events.

RESULTS

Eleven patients experienced hematuria, and the 5-year cumulative rate was 18%. Four patients experienced rectal hemorrhage, and the 5-year cumulative rate was 7%. ROC curve analysis demonstrated the following significant cut-off values: bladder V50 Gy: 43% (p=0.02) and V40 Gy: 50% (p=0.03) for hematuria, and rectum V60 Gy: 13% (p=0.04) and V50 Gy: 33% (p=0.03) for rectal hemorrhage.

CONCLUSION

This is the first study to identify dose constraints that may reduce hematuria and rectal hemorrhage in patients receiving radiotherapy in the postoperative setting.

Impact of advanced radiotherapy techniques and dose intensification on toxicity of salvage radiotherapy after radical prostatectomy

The safety and efficacy of dose-escalated radiotherapy with intensity-modulated radiotherapy (IMRT) and image-guided radiotherapy (IGRT) remain unclear in salvage radiotherapy (SRT) after radical prostatectomy. We examined the impact of these advanced radiotherapy techniques and dose intensification on the toxicity of SRT. This multi-institutional retrospective study included 421 patients who underwent SRT at the median dose of 66 Gy in 2-Gy fractions. IMRT and IGRT were used for 225 (53%) and 321 (76%) patients, respectively. At the median follow-up of 50 months, the cumulative incidence of late grade 2 or higher gastrointestinal (GI) and genitourinary (GU) toxicities was 4.8% and 24%, respectively. Multivariate analysis revealed that the non-use of either IMRT or IGRT, or both (hazard ratio [HR] 3.1, 95% confidence interval [CI] 1.8-5.4, p < 0.001) and use of whole-pelvic radiotherapy (HR 7.6, CI 1.0-56, p = 0.048) were associated with late GI toxicity, whereas a higher dose ≥68 Gy was the only factor associated with GU toxicities (HR 3.1, CI 1.3-7.4, p = 0.012). This study suggested that the incidence of GI toxicities can be reduced by IMRT and IGRT in SRT, whereas dose intensification may increase GU toxicity even with these advanced techniques.

Does Interfraction Cone Beam Computed Tomography Improve Target Localization in Prostate Bed Radiotherapy?

Purpose:

In this prospective phase II study, we investigated whether cone beam computed tomography scan was a superior method of image-guided radiotherapy relative to 2D orthogonal kilovoltage images in the post-radical prostatectomy setting.

Methods:

A total of 419 treatment fractions were included in this analysis. The shifts required to align the patient for each treatment were performed using 3D matching between cone beam computed tomography scans and the corresponding computed tomography images used for planning. This was compared with the shifts obtained from 2D orthogonal kilovoltage images, matching with the corresponding digitally reconstructed radiographs. Patients did not have fiducials inserted to assist with localization. Interfractional changes in the bladder and rectal volumes were subsequently measured on the cone beam computed tomography images for each fraction and compared to the shift differences between orthogonal kilovoltage and cone beam computed tomography scans. The proportion of treatment fractions with a shift difference exceeding the planning target volume of 7 mm, between orthogonal kilovoltage and cone beam computed tomography scans, was calculated.

Results:

The mean vertical, lateral, and longitudinal shifts resulted from 2D match between orthogonal kilovoltage images and corresponding digitally reconstructed radiographs were 0.353 cm (interquartile range: 0.1-0.5), 0.346 cm (interquartile range: 0.1-0.5), and 0.289 cm (interquartile range: 0.1-0.4), compared to 0.388 cm (interquartile range: 0.1-0.5), 0.342 cm (interquartile range: 0.1-0.5), and 0.291 cm (interquartile range: 0.1-0.4) obtained from 3D match between cone beam computed tomography and planning computed tomography scan, respectively. Our results show a significant difference between the kilovoltage and cone beam computed tomography shifts in the anterior–posterior direction (P = .01). The proportion of treatment fractions in which the differences in kilovoltage and cone beam computed tomography shifts between exceeded the 7 mm planning target volume margin was 6%, 2%, and 3% in the anterior–posterior, lateral, and superior–inferior directions, respectively.

Conclusion:

We prospectively demonstrated that the daily use of volumetric cone beam computed tomography for treatment localization in post-radical prostatectomy patients demonstrated an increased need for a shift in patient position. This suggests that in post-radical prostatectomy patients the daily cone beam computed tomography imaging improved localization of the prostate bed and may have prevented a limited number of geographic misses, compared to daily kilovoltage imaging that was not assisted with fiducials.

Hypofractionated postoperative helical tomotherapy in prostate cancer: a mono-institutional report of toxicity and clinical outcomes

Purpose

This is a mono-institutional study of acute and late toxicities and early biochemical control of a retrospective series of 75 prostate cancer patients treated with moderate postoperative hypofractionation delivered by helical tomotherapy (HT).

Patients and methods

From April 2013 to June 2017, 75 patients received adjuvant (n=37) or salvage (n=38) treatment, delivering to prostate bed a total dose of 63.8 Gy (equivalent dose in 2-Gy fractions=67.4 Gy) using 2.2 Gy fractions. Whole-pelvis irradiation was performed in 63% of cases (median dose, 49.3 Gy; range, 48–55.1 Gy). Concurrent hormonal therapy was administered in 46% of cases. Common Terminology Criteria for Adverse Events (version 4.0) was adopted for acute and late genitourinary (GU) and gastrointestinal (GI) toxicity evaluations. Biochemical progression was defined as PSA level increase of ≥0.2 or more above the postoperative radiotherapy (RT) nadir.

Results

Acute GU toxicities were as follows: G1 in 46% and G2 in 4%, detecting no G≥3 events. For GI toxicity, we recorded G1 in 36% and G2 in 18%. With a median follow-up of 30 months (range, 12–58 months), we found late toxicity G2 GI in 6.6% and G≥2 GU in 5.3%, including two patients who underwent surgical incontinence correction. Acute GI≥2 toxicity and diabetes were found to be predictive of late GI≥2 toxicity (P=0.04 and P=0.0019). Actuarial 2- and 3-year biochemical recurrence-free survivals were 88% and 73%, respectively, for the entire population.

Conclusion

In our experience, moderate hypofractionated postoperative RT with HT was feasible and safe, with reports of low incidence of toxicity and promising biochemical control rates.

Treatment-related toxicity in men who received Intensity-modulated versus 3D-conformal radiotherapy after radical prostatectomy: A national population-based study

BACKGROUND AND PURPOSE

In the post-prostatectomy setting the value of Intensity-modulated (IMRT) relative to 3D-conformal radiotherapy (3D-CRT) in reducing toxicity remains unclear. We compared genitourinary (GU) and gastrointestinal (GI) toxicity after post-prostatectomy IMRT or 3D-CRT.

MATERIALS AND METHODS

A population-based study of all patients treated with post-prostatectomy 3D-CRT (n = 2422) and IMRT (n = 603) was conducted between January 1 2010 and December 31 2013 in the English National Health Service. We identified severe GI and GU toxicity using a validated coding-framework and compared IMRT and 3D-CRT using a competing-risks proportional hazards regression analysis.

RESULTS

There was no difference in GI toxicity between patients who received IMRT and 3D-CRT (3D-CRT: 5.8 events/100 person-years; IMRT: 5.5 events/100 person-years; adjusted HR: 0.85, 95%CI: 0.63-1.13; p = 0.26). The GU toxicity rate was lower with IMRT but this effect was not statistically significant (3D-CRT: 5.4 events/100 person-years; IMRT: 3.8 events/100 person-years; adjusted HR: 0.76, 95%CI: 0.55-1.03; p = 0.08).

CONCLUSIONS

The use of post-prostatectomy IMRT compared to 3D-CRT is not associated with a statistically significant reduction in rates of severe GU and GI toxicity, although there is some evidence that GU toxicity is lower with IMRT. We would caution against rapid transition to post-prostatectomy IMRT until further evidence is available supporting its superiority.

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

Purpose

Dose-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 materials

164 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.

Results

With 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.

Conclusions

More 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.

Image-guided, whole-pelvic, intensity-modulated radiotherapy for biochemical recurrence following radical prostatectomy in high-risk prostate cancer patients

Background

The optimal field size of salvage radiotherapy (SRT) for biochemical recurrence, particularly for patients with high-risk prostate cancer, remains undefined. This retrospective analysis was performed to investigate oncological outcomes as well as treatment-related toxicity following salvage intensity-modulated radiotherapy (IMRT) to the whole pelvis and to compare the results with other studies implementing a small field size of the prostate bed.

Methods

The medical records of 170 patients with high-risk prostate cancer who received SRT for biochemical recurrence following prostatectomy were reviewed. Whole-pelvic IMRT was administered with a median dose of 66 Gy in 30 fractions. To improve treatment accuracy, an endorectal balloon device and daily cone-beam computed tomography were utilized. Androgen-deprivation therapy combined with SRT was administered to 97 (57.1%) patients.

Results

Eventually, 68 (40.0%) patients showed biochemical progression (BCP) after SRT. With a median follow-up period of 56 months, the 5-year BCP-free survival was 38.6%. The overall and cause-specific survival rates were 90.9% and 96.7%, respectively. Regarding BCP-free survival analysis, pathological T stage, persistent prostate-specific antigen (PSA) elevation after prostatectomy, and preSRT PSA level were significant prognostic factors on univariate analysis. On multivariate analysis, pathological T stage and preSRT PSA value retained their significance. Acute and late grade-3 genitourinary toxicities were observed in one (0.6%) and five (2.9%) patients, respectively. One patient each developed acute and late grade-3 gastrointestinal toxicity.

Conclusion

SRT to whole pelvis using IMRT and image guidance is as safe as SRT to the prostate bed, but its efficacy should be confirmed in ongoing randomized trials. PreSRT PSA was the only controllable prognostic factor, suggesting the benefit of early SRT.

Postoperative radiotherapy for prostate cancer: the sooner the better and potential to reduce toxicity even further

PURPOSE

To evaluate biochemical relapse-free survival (bRFS), overall survival (OS), late rectal and bladder toxicities in a retrospective single institution series, also applying an in-house software for biological dose calculation.

METHODS

258 patients submitted to radiotherapy after prostatectomy were considered. Differences between groups were calculated using the log-rank test and the relevant clinical and therapeutic variables were considered for multivariate analysis. PRODVH is an in-house system able to calculate mean dose-volume histograms (DVHs) of a series of patients, to convert them in biologically effective DVHs (BEDVHs) and allowing to compare them with ANOVA and t Student test.

RESULTS

Adjuvant radiotherapy (ART) and salvage radiotherapy (SRT) were performed in 131 (50.8%) and 127 patients (49.2%). At multivariate analysis advanced T stage, androgen deprivation total (ADT) and SRT resulted as independent variables related to a worst bRFS (p = 0.019, 0.001 and 0.02), while GS > 7 and SRT affected negatively OS (p 0.047 and 0.039). High grade toxicity events occurred mainly in patients treated with 3-dimensional conformal radiotherapy (3DCRT) (proctitis p = 0.006; cystitis: p = 0.041). A significantly more favorable mean rectum BEDVH for patients with G0 or G1 rectal toxicity was shown (p < 0.001). Mean BEDVH for both bladder (p < 0.01) and rectum (p < 0.05) were also significantly better for volumetric modulated arc therapy-image guided radiotherapy (VMAT-IGRT) plans than for 3DCRT plans.

CONCLUSION

ART is better than SRT in terms of bRFS and OS, particularly for more aggressive cases, advanced T stage and higher Gleason Score. Postoperative prostate cancer radiotherapy should be applied as soon as possible after surgery. The use of modern techniques such as VMAT-IGRT significantly reduces toxicity.

Outcomes and toxicity of 313 prostate cancer patients receiving helical tomotherapy after radical prostatectomy

Purpose

There are limited long-term data on patients treated with image guided intensity modulated radiation therapy (IG-IMRT) for prostate cancer recurrence or high-risk disease features after radical prostatectomy. We report single-institution results for patients treated with IG-IMRT and identify variables associated with outcome.

Methods and materials

This is a retrospective chart review consisting of 313 consecutive patients who were treated with adjuvant or salvage IG-IMRT from 2004 to 2013. Cox proportional hazards analysis was used to identify factors related to survival and toxicity. Toxicity was graded using the Common Terminology Criteria for Adverse Events Version 4.0.

Results

The median follow-up was 55 months (range, 6-131 months). The median pre-radiation therapy (RT) prostate-specific antigen (PSA) was 0.3 ng/mL (range, <0.01-55.4). The vast majority of patients (87%) received elective pelvic nodal irradiation (median dose: 45 Gy). Androgen deprivation therapy (ADT) was given to 39% of patients for a median of 9 months. Five-year biochemical progression-free survival and distant metastasis-free survival were 59% (95% confidence interval, 53%-66%) and 89% (95% confidence interval, 85%-93%), respectively. On multivariate analysis, higher pre-RT PSA (>0.2 ng/mL), biopsy Gleason score (≥7 [4+3]), and duration of ADT (>6 months) were significantly associated (P < .05) with biochemical progression-free survival. Actuarial late grade 3 genitourinary and gastrointestinal toxicities at 5 years were 10% and 2%, respectively.

Conclusion

Our results suggest that lower pre-RT PSA level and longer duration of ADT are associated with improved biochemical control. The incidence of late grade 3 gastrointestinal toxicity was low, but late grade 3 genitourinary toxicity was higher than anticipated.

Toxicity after post-prostatectomy image-guided intensity-modulated radiotherapy using Australian guidelines

INTRODUCTION

We evaluated single institution toxicity outcomes after post-prostatectomy radiotherapy (PPRT) via image-guided intensity-modulated radiation therapy (IG-IMRT) with implanted fiducial markers following national eviQ guidelines, for which late toxicity outcomes have not been published.

METHODS

Prospectively collected toxicity data were retrospectively reviewed for 293 men who underwent 64-66 Gy IG-IMRT to the prostate bed between 2007 and 2015.

RESULTS

Median follow-up after PPRT was 39 months. Baseline grade ≥2 genitourinary (GU), gastrointestinal (GI) and sexual toxicities were 20.5%, 2.7% and 43.7%, respectively, reflecting ongoing toxicity after radical prostatectomy. Incidence of new (compared to baseline) acute grade ≥2 GU and GI toxicity was 5.8% and 10.6%, respectively. New late grade ≥2 GU, GI and sexual toxicity occurred in 19.1%, 4.7% and 20.2%, respectively. However, many patients also experienced improvements in toxicities. For this reason, prevalence of grade ≥2 GU, GI and sexual toxicities 4 years after PPRT was similar to or lower than baseline (21.7%, 2.6% and 17.4%, respectively). There were no grade ≥4 toxicities.

CONCLUSIONS

Post-prostatectomy IG-IMRT using Australian contouring guidelines appears to have tolerable acute and late toxicity. The 4-year prevalence of grade ≥2 GU and GI toxicity was virtually unchanged compared to baseline, and sexual toxicity improved over baseline. This should reassure radiation oncologists following these guidelines. Late toxicity rates of surgery and PPRT are higher than following definitive IG-IMRT, and this should be taken into account if patients are considering surgery and likely to require PPRT.

Volumetric image-guided highly conformal radiotherapy of the prostate bed: Toxicity analysis

AIM

To evaluate toxicity of high conformal image-guided radiotherapy of the prostate bed.

BACKGROUND

Radiotherapy of the prostate bed has a pivotal role in the post-operative and salvage settings, but few clinical data are available on the use of daily image guidance in combination with highly conformal techniques, and data on long-term results are lacking.

MATERIALS AND METHODS

We analyzed 118 patients irradiated on the prostate bed using conformal plans processed with a micro-multileaf collimator, and daily checking treatment set-up with a cone-beam CT system. Correlation between toxicity and clinical-dosimetric parameters was assessed by the Cox regression model and log-rank test. Survival analyses were performed with the Kaplan-Meier method.

RESULTS

Median follow-up was 54.08 months. Late grade ≥2 gastro-intestinal (GI) and genito-urinary (GU) toxicity were 3.4% and 4.2%, respectively. Actuarial 4-year late grade ≥2 GI and GU toxicities were 4% and 6%, respectively. Four-year relapse-free survival was 87%. At log-rank test, acute grade ≥2 GI toxicity is associated with the use of antihypertensives (p = 0.03), and there is a trend toward significance between the use of anticoagulants and late grade ≥2 GI toxicity (p = 0.07). At Cox analysis, acute grade ≥2 GU toxicity is correlated with the percentage of bladder volume receiving more than 65 Gy (p = 0.02, HR 1.87 CI 1.25-2.8), and the maximal dose to the rectum is correlated to the development of late grade ≥2 GI toxicity (p = 0.03, HR 2.75 CI 1.10-6.9).

CONCLUSIONS

Conformal volumetric image-guided radiotherapy of the prostate bed leads to low toxicity rates.

Acute and late urinary toxicity following radiation in men with an intact prostate gland or after a radical prostatectomy: A secondary analysis of RTOG 94-08 and 96-01

INTRODUCTION

To estimate the contribution of the prostate gland and prostatic urethral inflammation to urinary symptoms after radiation therapy for prostate cancer, we performed a secondary analysis of urinary toxicity after primary radiation to an intact prostate vs. postprostatectomy radiation to the prostatic fossa in protocols RTOG 94-08 and 96-01, respectively.

MATERIALS AND METHODS

Patients randomized to the radiation-alone arms (without hormone therapy) of the 2 trials were evaluated, including 104 men receiving primary prostate radiation to 68.4Gy on RTOG 94-08 and 371 men receiving 64.8Gy to the prostatic fossa on RTOG 96-01. Acute and late urinary toxicity were scored prospectively by RTOG scales. Chi-square test/logistic regression and cumulative incidence approach/Fine-Gray regression model were used for analyses of acute and late toxicity, respectively.

RESULTS

Grade≥2 acute urinary toxicity was significantly higher after primary prostatic radiation compared with postprostatectomy radiation (30.8% vs. 14.0%; P<0.001), but acute grade≥3 toxicity did not differ (3.8% vs. 2.7%; P = 0.54). After adjusting for age, primary radiation resulted in significantly higher grade≥2 acute urinary toxicity (odds ratio = 3.72; 95% CI: 1.65-8.37; P = 0.02). With median follow-up of 7.1 years, late urinary toxicity was not significantly different with primary vs. postprostatectomy radiation (5-year grade≥2: 16.7% vs. 18.3%; P = 0.65; grade≥3: 6.0% vs. 3.3%; P = 0.24).

CONCLUSIONS

Primary radiation to an intact prostate resulted in higher grade≥2 acute urinary toxicity than radiation to the prostatic fossa, with no difference in late urinary toxicity. Thus, a proportion of acute urinary toxicity in men with an intact prostate may be attributable to inflammation of the prostatic gland or urethra.

[Clinical to planning target volume margins in prostate cancer radiotherapy]

The knowledge of inter- and intrafraction motion and deformations of the intrapelvic target volumes (prostate, seminal vesicles, prostatectomy bed and lymph nodes) as well as the main organs at risk (bladder and rectum) allow to define rational clinical to planning target volume margins, depending on the different radiotherapy techniques and their uncertainties. In case of image-guided radiotherapy, prostate margins and seminal vesicles margins can be between 5 and 10mm. The margins around the prostatectomy bed vary from 10 to 15mm and those around the lymph node clinical target volume between 7 and 10mm. Stereotactic body radiotherapy allows lower margins, which are 3 to 5mm around the prostate. Image-guided and stereotactic body radiotherapy with adequate margins allow finally moderate or extreme hypofractionation.

Salvage Radiation Therapy Dose Response for Biochemical Failure of Prostate Cancer After Prostatectomy-A Multi-Institutional Observational Study

PURPOSE

To determine whether a dose-response relationship exists for salvage radiation therapy (RT) of biochemical failure after prostatectomy for prostate cancer.

METHODS AND MATERIALS

Individual data from 1108 patients who underwent salvage RT at 10 academic centers were pooled. The cohort was enriched for selection criteria more likely associated with tumor recurrence in the prostate bed (margin positive and pre-RT prostate-specific antigen [PSA] level of ≤2.0 ng/mL) and without the confounding of planned androgen suppression. The cumulative incidence of biochemical failure and distant metastasis over time was computed, and competing risks hazard regression models were used to investigate the association between potential predictors and these outcomes. The association of radiation dose with outcomes was the primary focus.

RESULTS

With a 65.2-month follow-up duration, the 5- and 10-year estimates of freedom from post-RT biochemical failure (PSA level >0.2 ng/mL and rising) was 63.5% and 49.8%, respectively, and the cumulative incidence of distant metastasis was 12.4% by 10 years. A Gleason score of ≥7, higher pre-RT PSA level, extraprostatic tumor extension, and seminal vesicle invasion were associated with worse biochemical failure and distant metastasis outcomes. A salvage radiation dose of ≥66.0 Gy was associated with a reduced cumulative incidence of biochemical failure, but not of distant metastasis.

CONCLUSIONS

The use of salvage radiation doses of ≥66.0 Gy are supported by evidence presented in the present multicenter pooled analysis of individual patient data. The observational reporting method, limited sample size, few distant metastasis events, modest follow-up duration, and elective use of salvage therapy might have diminished the opportunity to identify an association between the radiation dose and this endpoint.

Gaps between Evidence and Practice in Postoperative Radiotherapy for Prostate Cancer: Focus on Toxicities and the Effects on Health-Related Quality of Life

Adjuvant radiotherapy (ART) after prostatectomy for patients with high-risk features [extracapsular extension (ECE), seminal vesicle invasion (SVI), and positive margin] has been shown to be associated with improved biochemical disease-free survival in three large randomized trials and with improved overall survival in one. Similarly, salvage radiotherapy (SRT) can effectively achieve biochemical control in a significant proportion of patients with a rising PSA after surgery. Nonetheless, both approaches of postoperative RT remain highly underutilized. This might be partly due to concerns with overtreatment inherent to adjuvant approaches, and/or hesitance about causing radiation toxicities and their subsequent effects on the patient's quality of life. Herein, we review the literature lending evidence to these arguments. We show recent series of ART/SRT and their low rates of acute and long-term toxicities, translating only in transient decline in quality-of-life (QoL) outcomes. We conclude that concerns with side effects should not preclude the recommendation of an effective and curative-intent therapy for men with prostate cancer initially treated with radical surgery.

Rationale and development of image-guided intensity-modulated radiotherapy post-prostatectomy: the present standard of care?

The indications for post-prostatectomy radiotherapy have evolved over the last decade, although the optimal timing, dose, and target volume remain to be well defined. The target volume is susceptible to anatomical variations with its borders interfacing with the rectum and bladder. Image-guided intensity-modulated radiotherapy has become the gold standard for radical prostate radiotherapy. Here we review the current evidence for image-guided techniques with intensity-modulated radiotherapy to the prostate bed and describe current strategies to reduce or account for interfraction and intrafraction motion.

Hypofractionated IMRT of the prostate bed after radical prostatectomy: acute toxicity in the PRIAMOS-1 trial

PURPOSE

Hypofractionated radiation therapy as primary treatment for prostate cancer is currently being investigated in large phase 3 trials. However, there are few data on postoperative hypofractionation. The Radiation therapy for the Prostate Bed With or Without the Pelvic Lymph Nodes (PRIAMOS 1) trial was initiated as a prospective phase 2 trial to assess treatment safety and toxicity of a hypofractionated intensity modulated radiation therapy (IMRT) of the prostate bed.

METHODS AND MATERIALS

From February to September 2012, 40 patients with indications for adjuvant or salvage radiation therapy were enrolled. One patient dropped out before treatment. Patients received 54 Gy in 18 fractions to the prostate bed with IMRT and daily image guidance. Gastrointestinal (GI) and genitourinary (GU) toxicities (according to National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.0) were recorded weekly during treatment and 10 weeks after radiation therapy.

RESULTS

Overall acute toxicity was favorable, with no recorded adverse events grade ≥3. Acute GI toxicity rates were 56.4% (grade 1) and 17.9% (grade 2). Acute GU toxicity was recorded in 35.9% of patients (maximum grade 1). Urinary stress incontinence was not influenced by radiation therapy. The incidence of grade 1 urinary urge incontinence increased from 2.6% before to 23.1% 10 weeks after therapy, but grade 2 urge incontinence remained unchanged.

CONCLUSIONS

Postoperative hypofractionated IMRT of the prostate bed is tolerated well, with no severe acute side effects.

Recent advances in radiation oncology: intensity-modulated radiotherapy, a clinical perspective

Radiotherapy plays an important role in the treatment of various malignancies, and intensity-modulated radiotherapy (IMRT) is an attractive option because it can deliver precise conformal radiation doses to the target while minimizing the dose to adjacent normal tissues. IMRT provides a highly conformal dose distribution by modulating the intensity of the radiation beam. A number of malignancies have been targeted by IMRT; this work reviews published data on the major disease sites treated with IMRT. The dosimetric advantage of IMRT has resulted in the significant reduction of adverse effects in some tumors. However, there are few clinical trials comparing IMRT and three-dimensional conformal radiotherapy (3D-CRT), and no definite increase in survival or the loco-regional control rate by IMRT has been demonstrated in many malignancies. IMRT also requires greater time and resources to complete compared to 3D-CRT. In addition, the cost-effectiveness of IMRT versus 3D-CRT has not yet been established.

Intensified adjuvant treatment of prostate carcinoma: feasibility analysis of a phase I/II trial

PURPOSE

To perform a preliminary feasibility acute and late toxicity evaluation of an intensified and modulated adjuvant treatment in prostate cancer (PCa) patients after radical prostatectomy.

MATERIAL AND METHODS

A phase I/II has been designed. Eligible patients were 79 years old or younger, with an ECOG of 0-2, previously untreated, histologically proven prostate adenocarcinoma with no distant metastases, pT2-4 N0-1, and with at least one of the following risk factors: capsular perforation, positive surgical margins, and seminal vesicle invasion. All patients received a minimum dose on tumor bed of 64.8 Gy, or higher dose (70.2 Gy; 85.4%), according to the pathological stage, pelvic lymph nodes irradiation (57.7%), and/or hormonal therapy (69.1%).

RESULTS

123 patients were enrolled and completed the planned treatment, with good tolerance. Median follow-up was 50.6 months. Grade 3 acute toxicity was only 2.4% and 3.3% for genitourinary (GU) and gastrointestinal (GI) tract, respectively. No patient had late grade 3 GI toxicity, and the GU grade 3 toxicity incidence was 5.8% at 5 years. 5-year BDSF was 90.2%.

CONCLUSIONS

A modulated and intensified adjuvant treatment in PCa was feasible in this trial. A further period of observation can provide a complete assessment of late toxicity and confirm the BDSF positive results.

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.

Does transperitoneal minimally invasive radical prostatectomy increase the amount of small bowel receiving salvage radiation?

INTRODUCTION

Transperitoneal minimally invasive radical prostatectomy (MIRP) has become first choice for several urologists and patients dealing with localized prostate cancer. We evaluate the effect of postoperative radiation on the small bowel in patients who underwent extraperitoneal open versus transperitoneal MIRP.

METHODS

We reviewed all patients who received postoperative radiation from 2006 to 2010. Planning target volume (PTV) and surrounding organs, including the small bowel, were delineated. The presence of the small bowel in PTV and its volume in receiving each dose level were analyzed.

RESULTS

A total of 122 patients were included: 26 underwent MIRP and 96 underwent open prostatectomy. The median age of patients was 66 years, with median body mass index 27 kg/m(2). The total PTV dose was 66 Gy, with the minimum and maximum doses received by the small bowel 0.4 and 66.4 Gy, respectively. The maximum volume of small bowel that received the safe limit of 40 Gy was 569 cm(3). Of the 26 patients who underwent MIRP, 12 (46%) had small bowel identified inside the PTV compared to 57 (59%) among patients who underwent open prostatectomy (p = 0.228). The mean volume of the small bowel receiving 40 Gy was 26 and 67 cm(3) in open and MIRP groups, respectively (p = 0.006); the incidence of acute complications was the same in both groups.

CONCLUSIONS

Higher volumes of the small bowel are subjected to significant radiation after MIRP procedures compared to open procedures; however, we could not demonstrate any impact on acute complications. Whether there is a difference in late complications remains to be evaluated.

Three Years of Salvage IMRT for Prostate Cancer: Results of the Montpellier Cancer Center

Background. To assess the feasibility of salvage intensity-modulated radiation Therapy (IMRT) and to examine clinical outcome. Patients and Methods. 57 patients were treated with salvage IMRT to the prostate bed in our center from January, 2007, to February, 2010. The mean prescription dose was 68 Gy in 34 fractions. Forty-four patients received concomitant androgen deprivation. Results. Doses to organs at risk were low without altering target volume coverage. Salvage IMRT was feasible without any grade 3 or 4 acute gastrointestinal or urinary toxicity. With a median follow-up of 21 months, one grade 2 urinary and 1 grade ≥2 rectal late toxicities were reported. Biological relapse-free survival was 96.5% (2.3% (1/44) relapsed with androgen suppression and 7.7% (1/13) without). Conclusion. Salvage IMRT is feasible and results in low acute and chronic side-effects. Longer follow-up is warranted to draw conclusions in terms of oncologic control.

Post-prostatectomy image-guided radiation therapy: evaluation of toxicity and inter-fraction variation using online cone-beam CT

PURPOSE

The purpose of this study is to assess the acute and late genitourinary (GU) and gastrointestinal (GI) toxicities of cone-beam computed tomography (CBCT) guided conformal adjuvant and salvage post-prostatectomy radiotherapy (RT) compared with RT with port films.

MATERIALS AND METHODS

Sixty-eight patients (group 1) were treated with RT following radical prostatectomy (RP) using CBCT-guided conformal RT to a median dose of 68.4Gy. CBCT images were acquired three to five times weekly and were automatically co-registered to a reference CT. A comparative group (group 2) included 150 patients who received post-RP RT with weekly port films to a median dose of 64.8Gy. GU and GI toxicities were graded in both the acute and late settings using Radiation Therapy Oncology Group criteria. Associations between toxicity and study variables were evaluated by odds ratios (ORs) estimated by logistic regression.

RESULTS

Grades 2 and 3 acute GU toxicity were experienced by 13% (n=9) and 2% (n=1) of patients in group 1, respectively, while 13% (n=19) had grade 2 acute GU toxicity in the control group (group 2). Grade 2 acute GI toxicity was experienced by 13% (n=9) and 15% (n=23) in groups 1 and 2, respectively. Acute GU (P=0.67) and GI (P =0.84) toxicities were not significantly different between the two groups. There were no associations detected between CBCT and acute GI toxicity (OR 0.76, P=0.57) or acute GU (OR 1.16, P=0.75). Increased odds of acute GU toxicity were observed for doses>68.4Gy (OR 12.81, P=0.04), which were only delivered in the CBCT group. CBCT mean variations (standard deviation) for 1053 fractions were 2.8mm (2.8), 2.0mm (2.4) and 3.1mm (2.9) in the left-to-right, anterior-to-posterior (AP) and superior-to-inferior (SI) axes, respectively. Corrective shifts for variance≥5mm were required for 15%, 6% and 19% of fractions in the left-to-right, anterior-to-posterior and superior-to-inferior axes, respectively.

CONCLUSIONS

Rates of acute toxicity with CBCT-guided post-RP RT to 68.4Gy were similar to treatment to 64.8Gy without image-guidance RT. Acceptable early toxicity profiles suggest that CBCT is a reasonable strategy for image guidance, but the value of CBCT must be weighed against potential increased risk of secondary cancers due to increased radiation exposure.

A novel correction factor based on extended volume to complement the conformity index

OBJECTIVE

We propose a modified conformity index (MCI), based on extended volume, that improves on existing indices by correcting for the insensitivity of previous conformity indices to reference dose shape to assess the quality of high-precision radiation therapy and present an evaluation of its application.

METHODS

In this paper, the MCI is similar to the conformity index suggested by Paddick (CI(Paddick)), but with a different correction factor. It is shown for three cases: with an extended target volume, with an extended reference dose volume and without an extended volume. Extended volume is generated by expanding the original volume by 0.1-1.1 cm isotropically. Focusing on the simulation model, measurements of MCI employ a sphere target and three types of reference doses: a sphere, an ellipsoid and a cube. We can constrain the potential advantage of the new index by comparing MCI with CI(Paddick). The measurements of MCI in head-neck cancers treated with intensity-modulated radiation therapy and volumetric-modulated arc therapy provide a window on its clinical practice.

RESULTS

The results of MCI for a simulation model and clinical practice are presented and the measurements are corrected for limited spatial resolution. The three types of MCI agree with each other, and comparisons between the MCI and CI(Paddick) are also provided.

CONCLUSION

The results from our analysis show that the proposed MCI can provide more objective and accurate conformity measurement for high-precision radiation therapy. In combination with a dose-volume histogram, it will be a more useful conformity index.

Postprostatectomy radiation therapy: an evidence-based review

While the majority of men with localized prostate cancer who undergo a radical prostatectomy will remain disease free, men with certain clinical and pathological features are known to be at an increased risk for developing a biochemical recurrence and, ultimately, distant metastatic disease. The optimal management of these patients continues to be a source of controversy. To date, three randomized Phase III trials have demonstrated that adjuvant radiation therapy (ART) for patients with certain adverse pathological features results in an improvement in several clinically-relevant end points, including biochemical recurrence-free survival and overall survival. Despite the evidence from these trials showing a benefit for ART, many believe that ART results in overtreatment and unwarranted treatment morbidity for a significant number of patients. Many physicians, therefore, instead advocate for close observation followed by early salvage radiation therapy (SRT) at the time of a biochemical recurrence. The purpose of this review is to evaluate the evidence for and to distinguish between ART and early SRT. We will also highlight current and future areas of research for this patient population, including radiation treatment dose escalation, hypofractionation and androgen deprivation therapy. We will also discuss the cost–effectiveness of ART and early SRT.

Can early implementation of salvage radiotherapy for prostate cancer improve the therapeutic ratio? A systematic review and regression meta-analysis with radiobiological modelling

PURPOSE

For prostate cancer that is thought to be locally recurrent after prostatectomy, the optimal timing, dose and techniques for salvage radiotherapy (SRT) have not been established. Here we perform a systematic review of published reports including regression meta-analysis and radiobiologic modelling to identify predictors of biochemical disease control and late toxicity.

METHODS

We performed a review of published series reporting treatment outcomes following SRT. Studies with at least 30 patients, median PSA before SRT of less than 2.0 ng/mL, and median follow-up of greater than 36 months were identified. Univariate and multivariate analyses were performed to test Gleason Score, SRT dose, SRT timing, pre-SRT PSA, whole pelvic irradiation and androgen deprivation therapy as predictors of 5-year biochemical progression-free survival (bPFS) and severe (grade≥3) late GI and GU toxicity. bPFS and toxicity data were fit to tumour control probability and normal tissue complication probability models, respectively.

RESULTS

Twenty-five articles met the inclusion criteria for this analysis. Five-year bPFS ranged from 25% to 70%. Severe late GI toxicity rates were 0% to 9%, and severe late GU toxicity rates were 1-11%. On multivariate analysis, bPFS increased with SRT dose by 2.5% per Gy and decreased with pre-SRT PSA by 18.3% per ng/mL (p<0.001). Late GI and GU toxicity increased with SRT dose by 1.2% per Gy (p=0.012) and 0.7% per Gy (p=0.010), respectively. Radiobiological models demonstrate the interaction between pre-SRT PSA, SRT dose and bPFS. For example, an increase in pre-SRT PSA from 0.4 to 1.0 ng/mL increases the SRT dose required to achieve a 50% bPFS rate from 60 to 70Gy. This could increase the rate of severe late toxicity by approximately 10%.

CONCLUSION

Biochemical control rates following SRT increase with SRT dose and decrease with pre-SRT PSA. Severe late GI and GU toxicity rates also increase with SRT dose. Radiobiological models suggest that the therapeutic ratio of SRT may be improved by initiating treatment at low PSA levels.

Improved toxicity profile following high-dose postprostatectomy salvage radiation therapy with intensity-modulated radiation therapy

BACKGROUND

With salvage radiation therapy (SRT) in the postprostatectomy setting, the need to deliver sufficient radiation doses to achieve a high probability of tumor control is balanced with the risk of increased toxicity. Intensity-modulated radiation therapy (IMRT) in the postprostatectomy salvage setting is gaining interest as a treatment strategy.

OBJECTIVE

Compare acute and late toxicities in patients treated with IMRT and three-dimensional conformal radiation therapy (3D-CRT) in the postprostatectomy salvage setting.

DESIGN, SETTING, AND PARTICIPANTS

A total of 285 patients who were treated at our institution between 1988 and 2007 with SRT after radical prostatectomy for biochemical recurrence were identified. All medical records were reviewed and toxicity recorded. Median follow-up was 60 mo.

INTERVENTION

All patients were treated with SRT with either 3D-CRT (n=109) or IMRT (n=176). A total of 205 patients (72%) were treated with doses ≥70Gy.

MEASUREMENTS

Late gastrointestinal (GI) and genitourinary (GU) toxicities were recorded using the Common Terminology Criteria for Adverse Events v. 3.0 definition.

RESULTS AND LIMITATIONS

The 5-yr actuarial rates of late grade ≥2 GI and GU toxicity were 5.2% and 17.0%, respectively. IMRT was independently associated with a reduction in grade ≥2 GI toxicity compared with 3D-CRT (5-yr IMRT, 1.9%; 5-yr 3D-CRT, 10.2%; p=0.02). IMRT was not associated with a reduction in risk of grade ≥2 GU toxicity (5-yr IMRT, 16.8%; 5-yr 3D-CRT, 15.8%; p=0.86), urinary incontinence (5-yr IMRT, 13.6%; 5-yr 3D-CRT, 7.9%; p=0.25), or grade 3 erectile dysfunction (5-yr IMRT, 26%; 5-yr 3D-CRT, 30%; p=0.82). Of patients who developed late grade ≥2 GI or GU toxicity, 38% and 44%, respectively, experienced resolution of their symptoms prior to the last follow-up.

CONCLUSIONS

Our experience with high-dose IMRT in the postprostatectomy salvage setting demonstrates that the treatment can be delivered safely with an associated reduction in late GI toxicity.

Primary radiotherapy versus radical prostatectomy for high-risk prostate cancer: a decision analysis

BACKGROUND

Two evidence-based therapies exist for the treatment of high-risk prostate cancer (PCA): external-beam radiotherapy (RT) with hormone therapy (H) (RT + H) and radical prostatectomy (S) with adjuvant radiotherapy (S + RT). Each of these strategies is associated with different rates of local control, distant metastasis (DM), and toxicity. By using decision analysis, the authors of this report compared the quality-adjusted life expectancy (QALE) between men with high-risk PCA who received RT + H versus S + RT versus a hypothetical trimodality therapy (S + RT + H).

METHODS

The authors developed a Markov model to describe lifetime health states after treatment for high-risk PCA. Probabilities and utilities were extrapolated from the literature. Toxicities after radiotherapy were based on intensity-modulated radiotherapy series, and patients were exposed to risks of diabetes, cardiovascular disease, and fracture for 5 years after completing H. Deterministic and probabilistic sensitivity analyses were performed to model uncertainty in outcome rates, toxicities, and utilities.

RESULTS

RT + H resulted in a higher QALE compared with S + RT over a wide range of assumptions, nearly always resulting in an increase of >1 quality-adjusted life year with outcomes highly sensitive to the risk of increased all-cause mortality from H. S + RT + H typically was superior to RT + H, albeit by small margins (<0.5 quality-adjusted life year), with results sensitive to assumptions about toxicity and radiotherapy efficacy.

CONCLUSIONS

For men with high-risk PCA, RT + H was superior to S + RT, and the result was sensitive to the risk of all-cause mortality from H. Moreover, trimodality therapy may offer local and distant control benefits that lead to optimal outcomes in a meaningful population of men.

Physician beliefs and practices for adjuvant and salvage radiation therapy after prostatectomy

PURPOSE

Despite results of randomized trials that support adjuvant radiation therapy (RT) after radical prostatectomy (RP) for prostate cancer with adverse pathologic features (APF), many clinicians favor selective use of salvage RT. This survey was conducted to evaluate the beliefs and practices of radiation oncologists (RO) and urologists (U) regarding RT after RP.

METHODS AND MATERIALS

We designed a Web-based survey of post-RP RT beliefs and policies. Survey invitations were e-mailed to a list of 926 RO and 591 U. APF were defined as extracapsular extension, seminal vesicle invasion, or positive surgical margin. Differences between U and RO in adjuvant RT recommendations were evaluated by comparative statistics. Multivariate analyses were performed to evaluate factors predictive of adjuvant RT recommendation.

RESULTS

Analyzable surveys were completed by 218 RO and 92 U (overallresponse rate, 20%). Adjuvant RT was recommended based on APF by 68% of respondents (78% RO, 44% U, p <0.001). U were less likely than RO to agree that adjuvant RT improves survival and/or biochemical control (p < 0.0001). PSA thresholds for salvage RT were higher among U than RO (p < 0.001). Predicted rates of erectile dysfunction due to RT were higher among U than RO (p <0.001). On multivariate analysis, respondent specialty was the only predictor of adjuvant RT recommendations.

CONCLUSIONS

U are less likely than RO to recommend adjuvant RT. Future research efforts should focus on defining the toxicities of post-RP RT and on identifying the subgroups of patients who will benefit from adjuvant vs. selective salvage RT.

Comparison of daily cone-beam computed tomography and kilovoltage planar imaging for target localization in prostate cancer patients following radical prostatectomy

PURPOSE

To review our initial clinical experience with image-guided radiation therapy (IGRT) using cone-beam computed tomography (CBCT) for prostate bed localization in post-radical prostatectomy (RP) patients and to compare shift and acute toxicity results to our previously published IGRT experience with daily kV planar imaging.

METHODS AND MATERIALS

Fifty patients treated with intensity modulated radiation therapy (IMRT) who had image guidance using either CBCT (n = 23) or kV planar imaging (n = 27) following RP were analyzed. Shifts were recorded in anterior-posterior, superior-inferior, and left-right axes. Total error was defined as the shift from initial setup based on skin markings to isocenter. Prostate bed motion (PBM) was defined as the change in prostate bed position relative to bones. Acute toxicity was graded according to the Radiation Therapy Oncology Group morbidity criteria.

RESULTS

Total error (TE) was measured in 752 CBCTs and 725 kV planar image pairs. PBM was measured in 585 CBCTs and 384 kV planar image pairs. The average magnitudes of TE and PBM in the anterior-posterior, superior-inferior, and left-right axes were greater with kV planar imaging compared to CBCT. Frequencies of acute grade 2 gastrointestinal (13% vs 7%, P = .7) and genitourinary (9% vs 11%, P = 1.0) were similar for CBCT and kV planar imaging patients. No toxicities greater than grade 2 were seen.

CONCLUSIONS

These results suggest that although the magnitudes of TE and PBM were larger with kV planar compared to CBCT, the levels of acute toxicity were acceptable and comparable between the two. The reasons for the differences are unclear, but we postulate that discernment of the prostate bed on the CBCT is more difficult. Further investigation is necessary to determine the reason for the shift differences and to evaluate the benefits and risks of CBCT in this setting.

[Vesicourethral anastomotic stricture following radical prostatectomy with or without postoperative radiotherapy]

OBJECTIVE

To know the incidence of vesicourethral anastomotic stricture in patients with prostate cancer treated with radical prostatectomy. Our secondary aim was to verify if postoperative radiotherapy increases the risk of presenting anastomotic stricture.

MATERIALS AND METHODS

We retrospectively checked the clinical records of patients that had undergone radical prostatectomy as their primary treatment between January 2000 and December 2008, with a minimum clinical follow-up of 12 months. Of the total patients, 258 met the foregoing requirements. Of them, 25 (9.6%) received postoperative radiotherapy, 12 (48%) received adjuvant radiotherapy and 13 (52%) received salvage radiotherapy. The mean age of the patients that received radiotherapy was 64 (46-77) years. The mean pre-radiotherapy PSA was 2.3 (0.04-26.1) ng/ ml. The mean time between surgery and radiotherapy was 17.4 (3-72) months. The mean dosage administered was 68 (58-70) Gy. The mean follow-up was 50.5 (15-177) months.

RESULTS

Of 25 prostatectomized patients that received radiotherapy, four (16%) developed vesicourethral anastomotic stricture. The mean time from the completion of the radiotherapy until the appearance of the stricture was 4 months (1-22). On the other hand, 36 (15.4%) of the prostatectomized patients that did not receive postoperative radiotherapy presented the same complication. Comparatively, we did not note significant differences between both groups (p=0.599).

CONCLUSIONS

In our retrospective review, postoperative radiotherapy did not significantly increase the incidence of vesicourethral anastomotic stricture.