Does Hormone Therapy Reduce Disease Recurrence in Prostate Cancer Patients Receiving Dose-Escalated Radiation Therapy? An Analysis of Radiation Therapy Oncology Group 94-06

Landscape of Carbon Ion Radiotherapy in Prostate Cancer: Clinical Application and Translational Research

Carbon ion radiotherapy (CIRT) is a useful and advanced technique for prostate cancer. This study sought to investigate the clinical efficacy and translational research for prostate cancer with carbon ion radiotherapy. We integrated the data from published articles, clinical trials websites, and our data. The efficacy of CIRT for prostate cancer was assessed in terms of overall survival, biochemical recurrence-free survival, and toxicity response. Up to now, clinical treatment of carbon ion radiotherapy has been carried in only five countries. We found that carbon ion radiotherapy induced little genitourinary and gastrointestinal toxicity when used for prostate cancer treatment. To some extent, it led to improved outcomes in overall survival, biochemical recurrence-free survival than conventional radiotherapy, especially for high-risk prostate cancer. Carbon ion radiotherapy brought clinical benefits for prostate cancer patients, and quality of life assessment indicated that CIRT affected patients to a lesser extent. Potential biomarkers from our omics-based study could be used to predict the efficacy of prostate cancer with CIRT. Carbon ion radiotherapy brought clinical benefits for prostate cancer patients. The omics-based translational research may provide insights into individualized therapy.

Prostate cancer dose-response, fractionation sensitivity and repopulation parameters evaluation from 25 international radiotherapy outcome data sets

OBJECTIVE

This study was undertaken to model the biochemical free survival at 5 years and to evaluate the parameters defining dose-response curve, dose-fractionation radiosensitivity and repopulation.

METHODS

It was carried out a literature search on Pubmed to retrieve data sets of patients treated with external beam radiation therapy of 1.8-4.0 Gy per fraction and overall treatment time of 3 to 10 weeks. 10 groups were identified, based on risk class and androgen deprivation therapy (ADT). Dose-response curve D₅₀ (dose at 50% probability of control) and g₅₀ (steepness), α/β (dose-fractionation radiosensitivity), and repopulation parameters, d_prolif and T_prolif , were calculated. Bootstrap-based cross-validation was performed and median and 95% CI (confidence interval) were evaluated.

RESULTS

25 data sets, including 20,310 patients, were considered. The median (95% CI) D₅₀ and g₅₀ values were 62 (CI 53 - 66) Gy and 1.6 (0.8 - 2.4). ADT patients showed lower values of D₅₀ and g₅₀ (57 ± 5 Gy and 1.1 ± 0.4) compared to no-ADT patients (65 ± 2 Gy and 2.3 ± 0.6), with p < 0.0001 and p = 0.002. If we did not consider any dependence on overall treatment time, the median (95% CI) value of α/β was 1.4 (1.0 - 1.9) Gy with p < 0.0001 for all patients. The median values of d_{proli f} and T_prolif were 0.0 to 0.3 Gy/d and 18-40 days.

CONCLUSION

Dose-response curve resulted dependent on risk class and ADT, with higher steepness for no-ADT patients. Low values of dose-fractionation radiosensitivity were found, supporting the use of moderate hypofractionated radiotherapy in each risk class. A limited dependence on repopulation was observed.

ADVANCES IN KNOWLEDGE

Prostate cancer response to moderate hypofractionated radiotherapy was reliably quantified considering risk class and androgen deprivation therapy.

Absolute percentage of biopsied tissue positive for Gleason pattern 4 disease (APP4) appears predictive of disease control after high dose rate brachytherapy and external beam radiotherapy in intermediate risk prostate cancer

BACKGROUND AND PURPOSE

To identify if, in intermediate risk prostate cancer (IR-PCa), the absolute percentage of biopsied tissue positive for pattern 4 disease (APP4) may be a predictor of outcome.

MATERIALS AND METHODS

411 patients with IR-PCa were retrospectively reviewed. APP4 was calculated based on biopsy reports. Multivariable competing risk analysis was then performed on optimized APP4 cutpoints to predict for biochemical failure (BF), androgen deprivation use for BF (ADT-BF) and development of metastases (MD).

RESULTS

Median follow-up for the cohort was 5.2 (Inter Quartile Range: 2.9-6.6) years. Median baseline PSA was 7.3 (5.3-9.8) ng/mL. 234 (56.9%) patients had T1 and 177 (43.1%) had T2 disease. Median APP4 was 2.00 (0.75-7.50)%. 38 (9.3%) patients experienced BF. The optimal cutpoint of APP4 for BF was >3.3% with an area under the curve (AUC) of 0.66. 17 (4.1%) received ADT-BF. The ADT-BF cutpoint was >6.6% with an AUC of 0.72. Eight (2.0%) developed MD. The MD cutpoint was >17.5% with an AUC of 0.86. Using APP4 >3.3 vs ≤ 3.3, log-transformed baseline PSA ln(PSA) (HR 2.5, 1.1-6.1; p = 0.037) and APP4 (HR 2.3, 1.1-4.7; p = 0.031) predicted for BF. Using APP4 >6.6 vs ≤ 6.6, ln(PSA) (HR 4.2, 1.4-12.4; p = 0.010) and APP4 (HR 3.7, 1.4-10.0; p = 0.009) were predictive of ADT-BF. APP4 >17.5 vs ≤ 17.5 alone was predictive of MD (HR 25.7, 4.9-135.3; p < 0.001).

CONCLUSION

APP4 cutpoints of >3.3%, >6.6% and >17.5% were strongly associated with increased risk of BF, ADT-BF and developing MD respectively. These findings may inform future practice when treating IR-PCa but require external validation.

Adjuvant androgen deprivation therapy for prostate cancer treated with radiation therapy

Radiation therapy is a commonly used curative modality for prostate cancer. The addition of androgen deprivation therapy (ADT) increases the curative potential of prostate radiotherapy (RT) in multiple subsets of patients. In addition to having an independent cytotoxic effect, current evidence suggests that androgen deprivation synergistically works with radiation therapy by preventing DNA repair. Given the wide-ranging toxicities of this therapy, clinicians must judiciously choose which patients may benefit from ADT and also consider the appropriate length of treatment. With recent advances in RT delivery, higher doses of radiation are currently used when compared with the dose used in historic trials, leading to the unanswered question of how RT dose interacts with ADT. Current and future clinical studies are attempting to further define the appropriate indications and patient populations for which ADT represents a clinically appropriate addition to prostate RT.

Impact of androgen-deprivation therapy on the outcome of dose-escalation prostate cancer radiotherapy without elective pelvic irradiation

The benefit of androgen-deprivation therapy (ADT) in combination with dose-escalated radiotherapy (DERT) for localized prostate cancer has not been determined in randomized studies. In this study, the benefit of ADT was assessed in patients uniformly treated with dose-escalated intensity-modulated radiation therapy (IMRT) to the prostate and seminal vesicles but not pelvis. In all, 419 patients with localized prostate adenocarcinoma underwent definitive IMRT (cumulative dose 78 Gy), with 32.6%, 33.1%, 32.1%, and 2.1% having T1 through T4 disease, respectively, and 51.2% having high-risk disease. ADT was given to 76.1% of patients. With a median follow-up of 60 months, 5-year biochemical failure-free, disease-free, and overall survival rates were 87%, 86%, and 87%, respectively. T stage was an independent predictor of all three rates. Five-year pelvic nodal recurrence rate was 2.9%. ADT improved biochemical failure-free and disease-free survival but not overall survival. ADT showed benefit in high-risk disease but not intermediate-risk disease. Late gastrointestinal and genitourinary toxicities ≥ grade 2 occurred in 11.0% and 6.7%, respectively. In conclusion, DERT with 78 Gy yields good disease control and low rate of pelvic nodal recurrence. ADT improves disease-free survival in patients with high-risk but not intermediate-risk disease.

The use of Hormonal Therapy to Augment Radiation Therapy in Prostate Cancer: An Update

PURPOSE OF REVIEW

Androgen deprivation therapy (ADT) is an important adjunctive therapy to external beam radiation therapy (RT) for the definitive management of prostate cancer. The role of ADT is well-established for locally advanced or high-risk disease in conjunction with standard doses of RT, but less defined for intermediate-risk disease or with dose-escalated RT. The goal of this review is to summarize evidence evaluating the combination of ADT/RT, focusing on recent trials and current controversies as they pertain to the practicing clinician.

RECENT FINDINGS

The benefit of ADT on biochemical control is maintained with dose-escalated RT according to recently reported phase III studies. Furthermore, there is now prospective, randomized evidence to support the addition of ADT to RT in the post-prostatectomy setting. ADT continues to play an important role for prostate cancer patients receiving dose-escalated RT. Future research is needed to identify subgroups most likely to benefit from this combination.

Clinical outcome and toxicity evaluation of simultaneous integrated boost pelvic IMRT/VMAT at different dose levels combined with androgen deprivation therapy in prostate cancer patients

Background

The role of dose escalation in patients receiving long-term androgen deprivation therapy (ADT) is still a controversial issue. The aim of the current study was to evaluate whether dose escalation for ≥76–80 Gy had any advantage in terms of biochemical disease-free survival (BDFS), distant metastasis-free survival (DMFS), or overall survival outcomes over the dose levels from 70 to <76 Gy.

Patients and methods

The study included a cohort of 24 patients classified with high- and intermediate-risk localized prostate cancer. All patients received ADT, starting at 4–6 months before radiation therapy and continued for a total period of 12–24 months in high-risk patients. The treatment plan was given in two phases. In the first phase, the nodal planning target volume (PTV) and the prostate PTV received 48.6 and 54 Gy, respectively, over 27 fractions. The treatment was applied through intensity-modulated radiation therapy or volumetric modulated arc therapy with a simultaneous integrated boost technique.

Results

More than half of the patients were in T3–T4 stage, 79.1% of the patients were in the high-risk category, and all patients received ADT. The rate of acute grade II gastrointestinal and genitourinary toxicities in all patients were 41.7% and 62.5%, respectively. The rate of freedom from grade II rectal toxicity at 2 years was 89% and 83% for patients treated with dose levels <76 and ≥76 Gy, respectively. The rate of BDFS at 2 years was 90% and 85% for doses <76 and ≥76 Gy, respectively. The DMFS at 2 years was 100% and 76% for dose levels <76 and ≥76 Gy, respectively.

Conclusion

In the current study, there were no significant differences in the BDFS and DMFS between patients treated with a dose of <76 and ≥76 Gy, including elective pelvic lymph nodes irradiation combined with ADT.

Comparison of neoadjuvant vs concurrent/adjuvant androgen deprivation in men with high-risk prostate cancer receiving definitive radiation therapy

PURPOSE

It is unknown whether there is a benefit to starting androgen deprivation therapy (ADT) prior to rather than concurrently with definitive radiation therapy in men with high-risk prostate cancer. We studied the National Cancer Data Base to determine whether the timing of ADT impacts survival.

METHODS

Men diagnosed with high-risk prostate adenocarcinoma who received external beam radiation therapy (EBRT) to a dose of 70-81 Gy along with ADT from 2004-2011 were included. Those who started ADT 42-90 days before EBRT were identified as having received neoadjuvant hormonal therapy (N-HT) and those who received ADT from 14 days before their radiation until 84 days after the start of EBRT were categorized as receiving concurrent/adjuvant treatment (C-HT). We used the log-rank test to compare Kaplan-Meier survival curves and multivariable Cox regression to assess the impact of covariables on overall survival (OS).

RESULTS

Among 11,491 included patients, those receiving N-HT were 1 year older (p<0.001) and more likely to have Gleason 8-10 disease (p = 0.01) and cT3-4 disease (p = 0.002). Men receiving N-HT had a 5-year and median OS of 80.6% and 111.4 months, respectively, compared to 78.3% and 108.9 months, respectively, in those receiving C-HT (p = 0.03). This benefit remained significant on multivariable analysis (hazard ratio 0.86, 95% confidence interval 0.77-0.96, p = 0.008). Duration of ADT was not available to report.

CONCLUSIONS

External beam radiation therapy with N-HT was associated with improved overall survival compared to C-HT. This study is hypothesis-generating and further studies are needed to best qualify the sequencing of hormone therapy with the duration of treatment.

78Gy with Fiducial Marker Image-Guided Radiotherapy in Prostate Cancer: Single Center Analysis of 301 Patients

AIM

In prostate cancer, fiducial marker image-guided radiotherapy (FMIGRT) allows correction of setup errors and interfraction physiological motion resulting in improved accuracy of target and sparing of at risk organs. We aim to report outcomes and toxicities observed in patients treated with dose escalation to 78Gy with FMIGRT in our center.

METHODS AND MATERIALS

Retrospective review of consecutive patients with histologically confirmed T1-4N0M0 localized prostate cancer treated with dose escalation to 78Gy with FMIGRT in our center. All patients had 3-D conformal radiotherapy. Duration of androgen deprivation therapy use was tailored to risk group. Toxicity was scored according to CTCAE.v04. Kaplan-Meier analysis was performed for freedom from biochemical failure (FFBF), prostate cancer-specific survival and overall survival.

RESULTS

Median follow-up was 48.6 months. Median duration of androgen deprivation therapy was 6 and 23 months in the intermediate- and high-risk group, respectively. FFBF at 5 years was 88.8%. FFBFs when stratified to risk groups were 100% for low risk, 88.9% for low-intermediate risk, 89.9% for high-intermediate risk and 85.4% for high risk, respectively. Acute severe toxicity (grade≥3) rate for both genitourinary (GU) and gastrointestinal (GI) was 1%. Late moderate-to-severe toxicity (grade≥2) rates for GU and GI were 15% and 17%, respectively, with severe (grade≥3) toxicity rate for GU and GI at 2% and 3%, respectively.

CONCLUSION

Dose escalation to 78Gy with FMIGRT in our series achieved good FFBF at 5 years with low acute and late toxicity rates. These results provide a good comparator cohort to our current use of image-guided intensity modulated radiotherapy.

Long-term outcomes of dose-escalated intensity modulated radiation therapy alone without androgen deprivation therapy for patients with intermediate and high-risk prostate cancer

Objective

The addition of androgen deprivation therapy (ADT) to conventional radiation therapy improves overall survival (OS) in intermediate- and high-risk prostate cancer. The benefit of ADT to added to dose-escalated radiotherapy is less clear. The aim of this study was to report disease control outcomes and to identify prognostic variables associated with favorable outcomes in patients with intermediate- and high-risk prostate cancer treated with dose-escalated radiation therapy without ADT.

Methods and materials

From September 2001 to March 2010, 127 patients with intermediate- or high-risk prostate cancer were treated with dose-escalated radiation otherapy without ADT. Biochemical recurrence-free survival (bRFS), distant metastases-free survival (DMFS), prostate cancer–specific mortality, and OS were assessed. Univariate and multivariate analyses using Cox regression modeling were performed.

Results

The median follow-up was 6.5 years, and the 5-year estimated bRFS, DMFS, prostate cancer–specific mortality, and OS for all patients was 89%, 96.1%, 98.4%, and 96.9% respectively. On multivariate analysis, factors that predict bRFS include risk group and PSA nadir, and factors that predict DMFS include perineural invasion, risk group, and PSA nadir.

Conclusions

Patients with favorable intermediate-risk cancer could likely be treated with dose-escalated radiation therapy without ADT. Patients with high-risk and unfavorable intermediate-risk cancer, perineural invasion, and PSA nadir ≥1ng/dL had worse outcomes and likely need distinct therapeutic approaches.

Short Androgen Suppression and Radiation Dose Escalation for Intermediate- and High-Risk Localized Prostate Cancer: Results of EORTC Trial 22991

Purpose

Up to 30% of patients who undergo radiation for intermediate- or high-risk localized prostate cancer relapse biochemically within 5 years. We assessed if biochemical disease-free survival (DFS) is improved by adding 6 months of androgen suppression (AS; two injections of every-3-months depot of luteinizing hormone–releasing hormone agonist) to primary radiotherapy (RT) for intermediate- or high-risk localized prostate cancer.

Patients and Methods

A total of 819 patients staged: (1) cT1b-c, with prostate-specific antigen (PSA) ≥ 10 ng/mL or Gleason ≥ 7, or (2) cT2a (International Union Against Cancer TNM 1997), with no involvement of pelvic lymph nodes and no clinical evidence of metastatic spread, with PSA ≤ 50 ng/mL, were centrally randomized 1:1 to either RT or RT plus AS started on day 1 of RT. Centers opted for one dose (70, 74, or 78 Gy). Biochemical DFS, the primary end point, was defined from entry until PSA relapse (Phoenix criteria) and clinical relapse by imaging or death of any cause. The trial had 80% power to detect hazard ratio (HR), 0.714 by intent-to-treat analysis stratified by dose of RT at the two-sided α = 5%.

Results

The median patient age was 70 years. Among patients, 74.8% were intermediate risk and 24.8% were high risk. In the RT arm, 407 of 409 patients received RT; in the RT plus AS arm, 403 patients received RT plus AS and three patients received RT only. At 7.2 years median follow-up, RT plus AS significantly improved biochemical DFS (HR, 0.52; 95% CI, 0.41 to 0.66; P < .001, with 319 events), as well as clinical progression-free survival (205 events, HR, 0.63; 95% CI, 0.48 to 0.84; P = .001). In exploratory analysis, no statistically significant interaction between treatment effect and dose of RT could be evidenced (heterogeneity P = .79 and P = .66, for biochemical DFS and progression-free survival, respectively). Overall survival data are not mature yet.

Conclusion

Six months of concomitant and adjuvant AS improves biochemical and clinical DFS of intermediate- and high-risk cT1b-c to cT2a (with no involvement of pelvic lymph nodes and no clinical evidence of metastatic spread) prostatic carcinoma, treated by radiation.

Improved survival with the addition of radiotherapy to androgen deprivation: questions answered and a review of current controversies in radiotherapy for non-metastatic prostate cancer

The contemporary standard of care for locally advanced high-risk prostate cancer includes a combination of dose-escalated radiotherapy (RT) plus androgen-deprivation therapy (ADT). However, 20 years ago, at the inception of the National Cancer Institute of Canada (NCIC) led study (NCIC Clinical Trials Group PR.3/Medical Research Council PR07/Intergroup T94-0110), the survival impact of prostate RT for high-risk disease was uncertain. Recently, Mason, Warde and colleagues presented the final results of this NCIC/MRC study (PMID: 25691677) randomizing 1,205 high-risk prostate cancer patients to ADT + RT vs. ADT alone. These updated results confirm substantial improvements with the addition of RT to ADT for the endpoints of overall survival (OS), disease-free survival (DFS), and biochemical recurrence. Close examination of subtleties of this trial's design highlight some of the most salient controversies in the field of prostate RT, including the risk-stratified roles of ADT, optimal ADT duration, and RT field design in the dose-escalated and intensity-modulated radiotherapy (IMRT) era.

Survival Outcomes of Whole-Pelvic Versus Prostate-Only Radiation Therapy for High-Risk Prostate Cancer Patients With Use of the National Cancer Data Base

PURPOSE/OBJECTIVES

The addition of whole pelvic (WP) compared with prostate-only (PO) radiation therapy (RT) for clinically node-negative prostate cancer remains controversial. The purpose of our study was to evaluate the survival benefit of adding WPRT versus PO-RT for high-risk, node-negative prostate cancer, using the National Cancer Data Base (NCDB).

METHODS AND MATERIALS

Patients with high-risk prostate cancer treated from 2004 to 2006, with available data for RT volume, coded as prostate and pelvis (WPRT) or prostate alone (PO-RT) were included. Multivariate analysis (MVA) and propensity-score matched analysis (PSM) were performed. Recursive partitioning analysis (RPA) based on overall survival (OS) using Gleason score (GS), T stage, and pretreatment prostate-specific antigen (PSA) was also conducted.

RESULTS

A total of 14,817 patients were included: 7606 (51.3%) received WPRT, and 7211 (48.7%) received PO-RT. The median follow-up time was 81 months (range, 2-122 months). Under MVA, the addition of WPRT for high-risk patients had no OS benefit compared with PO-RT (HR 1.05; P=.100). On subset analysis, patients receiving dose-escalated RT also did not benefit from WPRT (HR 1.01; P=.908). PSM confirmed no survival benefit with the addition of WPRT for high-risk patients (HR 1.05; P=.141). In addition, RPA was unable to demonstrate a survival benefit of WPRT for any subset. Other prognostic factors for inferior OS under MVA included older age (HR 1.25; P<.001), increasing comorbidity scores (HR 1.46; P<.001), higher T stage (HR 1.17; P<.001), PSA (HR 1.81; P<.001), and GS (HR 1.29; P<.001), and decreasing median county household income (HR 1.15; P=.011). Factors improving OS included the addition of androgen deprivation therapy (HR 0.92; P=.033), combination external beam RT plus brachytherapy boost (HR 0.71; P<.001), and treatment at an academic/research institution (HR 0.84; P=.002).

CONCLUSION

In the largest reported analysis of WPRT for patients with high-risk prostate cancer treated in the dose-escalated era, the addition of WPRT demonstrated no survival advantage compared with PO-RT.

Synergistic action of image-guided radiotherapy and androgen deprivation therapy

The combined use of androgen deprivation therapy (ADT) and image-guided radiotherapy (IGRT) can improve overall survival in aggressive, localized prostate cancer. However, owing to the adverse effects of prolonged ADT, it is imperative to identify the patients who would benefit from this combined-modality therapy relative to the use of IGRT alone. Opportunities exist for more personalized approaches in treating aggressive, locally advanced prostate cancer. Biomarkers--such as disseminated tumour cells, circulating tumour cells, genomic signatures and molecular imaging techniques--could identify the patients who are at greatest risk for systemic metastases and who would benefit from the addition of systemic ADT. By contrast, when biomarkers of systemic disease are not present, treatment could proceed using local IGRT alone. The choice of drug, treatment duration and timing of ADT relative to IGRT could be predicated on these personalized approaches to prostate cancer medicine. These novel treatment intensification and reduction strategies could result in improved prostate-cancer-specific survival and overall survival, without incurring the added expense of metabolic syndrome and other adverse effects of ADT in all patients.

Adjuvant versus neoadjuvant androgen deprivation with radiotherapy for prostate cancer: does sequencing matter?

INTRODUCTION/BACKGROUND

Androgen deprivation therapy (ADT) is typically provided neoadjuvantly and concurrently with radiotherapy (RT) in the management of intermediate and high-risk prostate cancer. Our objective was to compare outcomes between patients who received adjuvant ADT (ADJ), ie, immediately after the completion of RT, to those who received a neoadjuvant and concurrent regimen (NEO).

MATERIALS AND METHODS

From 1995 to 2002, 515 patients with prostate cancer were definitively treated with RT and ADT. NEO was provided 2 to 3 months before the start of RT (n = 311). ADJ was initiated immediately after the completion of RT (n = 204). Kaplan-Meier analysis was used to calculate biochemical relapse-free survival (bRFS), distant metastasis-free survival (DMFS), and overall survival (OS). Cox proportional hazards regression was used to examine the impact of ADT timing on outcomes.

RESULTS

Ten-year bRFS, DMFS, and OS rates were 61%, 80%, and 66%, respectively. Ten-year bRFS rates for ADJ versus NEO were 63% versus 60% (P = .98). Ten-year DMFS rates for ADJ versus NEO were both 80% (P = .60). Ten-year OS rates for ADJ versus NEO were 65% versus 67% (P = .98).

CONCLUSION

There was no significant difference in bRFS, DMFS, or OS between neoadjuvant versus adjuvant ADT in the setting of dose-escalated RT for localized prostate cancer. This suggests that the synergy between RT and androgen deprivation is independent of the sequencing of both modalities and that the initiation of RT does not need to be delayed for a course of neoadjuvant ADT.

Long-term outcomes from dose-escalated image-guided intensity-modulated radiotherapy with androgen deprivation: encouraging results for intermediate- and high-risk prostate cancer

PURPOSE

Dose-escalated (DE) radiotherapy in the setting of localized prostate cancer has been shown to improve biochemical disease-free survival (bDFS) in several studies. In the same group of patients, androgen deprivation therapy (ADT) has been shown to confer a survival benefit when combined with radiotherapy doses of up to 70 Gy; however, there is currently little long-term data on patients who have received high-dose intensity-modulated radiotherapy (IMRT) with ADT. We report the long-term outcomes in a large cohort of patients treated with the combination of DE image-guided IMRT (IG-IMRT) and ADT.

METHODS AND MATERIALS

Patients with localized prostate cancer were identified from a centralized database across an integrated cancer center. All patients received DE IG-IMRT, combined with ADT, and had a minimum follow up of 12 months post-radiotherapy. All relapse and toxicity data were collected prospectively. Actuarial bDFS, metastasis-free survival, prostate cancer-specific survival, and multivariate analyses were calculated using the SPSS v20.0 statistical package.

RESULTS

Seven hundred and eighty-two eligible patients were identified with a median follow up of 46 months. Overall, 4.3% of patients relapsed, 2.0% developed distant metastases, and 0.6% died from metastatic prostate cancer. At 5-years, bDFS was 88%, metastasis-free survival was 95%, and prostate cancer-specific survival was 98%. Five-year grade 2 genitourinary and gastrointestinal toxicity was 2.1% and 3.4%, respectively. No grade 3 or 4 late toxicities were reported. Pretreatment prostate specific antigen (P=0.001) and Gleason score (P=0.03) were significant in predicting biochemical failure on multivariate analysis.

CONCLUSION

There is a high probability of tumor control with DE IG-IMRT combined with androgen deprivation, and this is a technique with a low probability of significant late toxicity. Our long term results corroborate the safety and efficacy of treating with IG-IMRT to high doses and compares favorably with published series for the treatment of prostate cancer.

Simultaneous integrated boost plan comparison of volumetric-modulated arc therapy and sliding window intensity-modulated radiotherapy for whole pelvis irradiation of locally advanced prostate cancer

Concurrent radiotherapy to the pelvis plus a prostate boost with long-term androgen deprivation is a standard of care for locally advanced prostate cancer. IMRT has the ability to deliver highly conformal dose to the target while lowering irradiation of critical organs around the prostate. Volumetric-modulated arc therapy is able to reduce treatment time, but its impact on organ sparing is still controversial when compared to static gantry IMRT. We compared the two techniques in simultaneous integrated boost plans. Ten patients with locally advanced prostate cancer were included. The planning target volume (PTV) 1 was defined as the pelvic lymph nodes, the prostate, and the seminal vesicles plus setup margins. The PTV2 consisted of the prostate with setup margins. The prescribed doses to PTV1 and PTV2 were 54 Gy in 37 fractions and 74 Gy in 37 fractions, respectively. We compared simultaneous integrated boost plans by means of either a seven coplanar static split fields IMRT, or a one-arc (RA1) and a two-arc (RA2) RapidArc planning. All three techniques allowed acceptable homogeneity and PTV coverage. Static IMRT enabled a better homogeneity for PTV2 than RapidArc techniques. Sliding window IMRT and VMAT permitted to maintain doses to OAR within acceptable levels with a low risk of side effects for each organ. VMAT plans resulted in a clinically and statistically significant reduction in doses to bladder (mean dose IMRT: 50.1 ± 4.6Gy vs. mean dose RA2: 47.1 ± 3.9 Gy, p = 0.037), rectum (mean dose IMRT: 44± 4.5 vs. mean dose RA2: 41.6 ± 5.5 Gy, p = 0.006), and small bowel (V30 IMRT: 76.47 ± 14.91% vs. V30 RA2: 47.49 ± 16.91%, p = 0.002). Doses to femoral heads were higher with VMAT but within accepted constraints. Our findings suggest that simultaneous integrated boost plans using VMAT and sliding window IMRT allow good OAR sparing while maintaining PTV coverage within acceptable levels.

Short-term androgen-deprivation therapy improves prostate cancer-specific mortality in intermediate-risk prostate cancer patients undergoing dose-escalated external beam radiation therapy

PURPOSE

We investigated the benefit of short-term androgen-deprivation therapy (ADT) in patients with intermediate-risk prostate cancer (PC) receiving dose-escalated external beam radiation therapy.

METHODS AND MATERIALS

The present retrospective study comprised 710 intermediate-risk PC patients receiving external beam radiation therapy with doses of ≥81 Gy at a single institution from 1992 to 2005, including 357 patients receiving neoadjuvant and concurrent ADT. Prostate-specific antigen recurrence-free survival (PSA-RFS) and distant metastasis (DM) were compared using the Kaplan-Meier method and Cox proportional hazards models. PC-specific mortality (PCSM) was assessed using competing-risks analysis.

RESULTS

The median follow-up was 7.9 years. Despite being more likely to have higher PSA levels, Gleason score 4 + 3 = 7, multiple National Comprehensive Cancer Network intermediate-risk factors, and older age (P≤.001 for all comparisons), patients receiving ADT had improved PSA-RFS (hazard ratio [HR], 0.598; 95% confidence interval [CI], 0.435-0.841; P=.003), DM (HR, 0.424; 95% CI, 0.219-0.819; P=.011), and PCSM (HR, 0.380; 95% CI, 0.157-0.921; P=.032) on univariate analysis. Using multivariate analysis, ADT was an even stronger predictor of improved PSA-RFS (adjusted HR [AHR], 0.516; 95% CI, 0.360-0.739; P<.001), DM (AHR, 0.347; 95% CI, 0.176-0.685; P=.002), and PCSM (AHR, 0.297; 95% CI, 0.128-0.685; P=.004). Gleason score 4 + 3 = 7 and ≥50% positive biopsy cores were other independent predictors of PCSM.

CONCLUSIONS

Short-term ADT improves PSA-RFS, DM, and PCSM in patients with intermediate-risk PC undergoing dose-escalated external beam radiation therapy.

Addition of short-term androgen deprivation therapy to dose-escalated radiation therapy improves failure-free survival for select men with intermediate-risk prostate cancer

BACKGROUND

Dose-escalated (DE) radiation therapy (RT) and androgen deprivation therapy (ADT) improve prostate cancer outcomes over standard-dose RT. The benefit of adding ADT to DE-RT for men with intermediate-risk prostate cancer (IR-PrCa) is uncertain.

PATIENTS AND METHODS

We identified 636 men treated for IR-PrCa with DE-RT (>75Gy). The adult comorbidity evaluation-27 index classifed comorbidity. Kaplan-Meier and log-rank tests compared failure-free survival (FFS) with and without ADT.

RESULTS

Forty-five percent received DE-RT and 55% DE-RT with ADT (median 6 months). On Cox proportional hazard regression that adjusted for comorbidity and tumor characteristics, ADT improved FFS (adjusted hazard ratio 0.36; P = 0.004). Recursive partitioning analysis of men without ADT classified Gleason 4 + 3 = 7 or ≥50% positive cores as unfavorable disease. The addition of ADT to DE-RT improved 5-year FFS for men with unfavorable disease (81.6% versus 92.9%; P = 0.009) but did not improve FFS for men with favorable disease (96.3% versus 97.4%; P = 0.874). When stratified by comorbidity, ADT improved FFS for men with unfavorable disease and no or mild comorbidity (P = 0.006) but did not improve FFS for men with unfavorable disease and moderate or severe comorbidity (P = 0.380).

CONCLUSION

The addition of ADT to DE-RT improves FFS for men with unfavorable IR-PrCa, especially those with no or minimal comorbidity.

The current role of androgen deprivation in patients undergoing dose-escalated external beam radiation therapy for clinically localized prostate cancer

Purpose. To review existing literature on the role of androgen deprivation therapy (ADT) with dose escalated radiation therapy. Methods and Materials. A PubMed search was undertaken to identify relevant articles. Results. Multiple recent studies were identified examining the role of ADT in the current era of radiation dose-escalation. Among the reviewed studies, varying radiation doses and techniques, ADT regimens, and patient selection criteria were utilized. Conflicting results were reported, with some studies demonstrating a benefit of delivering a higher radiation dose with ADT. Other studies failed to show significant benefits with the addition of ADT to dose-escalated RT. Conclusions. The benefit of adding ADT to dose-escalated RT is still uncertain. Prospective randomized trials, several of which are ongoing, are necessary to more adequately examine this issue. In the interim, physicians and patients should continue to utilize the existing data to weigh the risks and benefits of each approach to therapy.

Carbon-ion radiation therapy for prostate cancer

In 1994, carbon-ion radiotherapy was started at the National Institute of Radiological Sciences using the Heavy-Ion Medical Accelerator in Chiba. Between June 1995 and March 2000, two phase I/II dose escalation studies (protocols 9402 and 9703) of hypofractionated carbon-ion radiotherapy for both early- and advance-stage prostate cancer patients had been carried out to establish radiotherapy technique and to determine the optimal radiation dose. To validate the feasibility and efficacy of hypofractionated carbon-ion radiotherapy, a phase II study (9904) was initiated in April 2000 using the shrinking field technique and the recommended dose fractionation (66 gray equivalents in 20 fractions over 5 weeks) obtained from the phase I/II studies, and was successfully completed in October 2003. The data from 175 patients in the phase II study showed the importance of an appropriate use of androgen deprivation therapy according to tumor risk group. Since November 2003, carbon-ion radiotherapy for prostate cancer was approved as "Highly Advanced Medical Technology" from the Ministry of Health, Labor, and Welfare, and since then approximately 1100 patients have received carbon-ion radiotherapy as of July 2011. In this review, we introduce our steps thorough three clinical trials carried out at National Institute of Radiological Sciences, and show the updated data of carbon-ion radiotherapy obtained from approximately 1000 prostate cancer patients. In addition, our recent challenge and future direction will be also described.

Molecular targets for radiation oncology in prostate cancer

Recent selected developments of the molecular science of prostate cancer (PrCa) biology and radiation oncology are reviewed. We present potential targets for molecular integration treatment strategies with radiation therapy (RT), and highlight potential strategies for molecular treatment in combination with RT for patient care. We provide a synopsis of the information to date regarding molecular biology of PrCa, and potential integrated research strategy for improved treatment of PrCa. Many patients with early-stage disease at presentation can be treated effectively with androgen ablation treatment, surgery, or RT. However, a significant portion of men are diagnosed with advanced stage/high-risk disease and these patients progress despite curative therapeutic intervention. Unfortunately, management options for these patients are limited and are not always successful including treatment for hormone refractory disease. In this review, we focus on molecules of extracellular matrix component, apoptosis, androgen receptor, RUNX, and DNA methylation. Expanding our knowledge of the molecular biology of PrCa will permit the development of novel treatment strategies integrated with RT to improve patient outcome.