Long-Term Outcome Following Three-Dimensional Conformal/Intensity-Modulated External-Beam Radiotherapy for Clinical Stage T3 Prostate Cancer

Urethra Sparing With Target Motion Mitigation in Dose-Escalated Extreme Hypofractionated Prostate Cancer Radiotherapy: 7-Year Results From a Phase II Study

Purpose

To explore whether the rectal distension-mediated technique, harnessing human physiology to achieve intrafractional prostate motion mitigation, enables urethra sparing by inverse dose painting, thus promoting dose escalation with extreme hypofractionated stereotactic ablative radiotherapy (SABR) in prostate cancer.

Materials and Methods

Between June 2013 and December 2018, 444 patients received 5 × 9 Gy SABR over 5 consecutive days. Rectal distension-mediated SABR was employed via insertion of a 150-cm³ air-inflated endorectal balloon. A Foley catheter loaded with 3 beacon transponders was used for urethra visualization and online tracking. MRI-based planning using Volumetric Modulated Arc Therapy - Image Guided Radiotherapy (VMAT-IGRT) with inverse dose painting was employed in delivering the planning target volume (PTV) dose and in sculpting exposure of organs at risk (OARs). A 2-mm margin was used for PTV expansion, reduced to 0 mm at the interface with critical OARs. All plans fulfilled D_mean ≥45 Gy. Target motion ≥2 mm/5 s motions mandated treatment interruption and target realignment prior to completion of the planned dose delivery.

Results

Patient compliance to the rectal distension-mediated immobilization protocol was excellent, achieving reproducible daily prostate localization at a patient-specific retropubic niche. Online tracking recorded ≤1-mm intrafractional target deviations in 95% of treatment sessions, while target realignment in ≥2-mm deviations enabled treatment completion as scheduled in all cases. The cumulative incidence rates of late grade ≥2 genitourinary (GU) and gastrointestinal (GI) toxicities were 5.3% and 1.1%, respectively. The favorable toxicity profile was corroborated by patient-reported quality of life (QOL) outcomes. Median prostate-specific antigen (PSA) nadir by 5 years was 0.19 ng/ml. The cumulative incidence rate of biochemical failure using the Phoenix definition was 2%, 16.6%, and 27.2% for the combined low/favorable–intermediate, unfavorable intermediate, and high-risk categories, respectively. Patients with a PSA failure underwent a ⁶⁸Ga-labeled prostate-specific membrane antigen (⁶⁸Ga-PSMA) scan showing a 20.2% cumulative incidence of intraprostatic relapses in biopsy International Society of Urological Pathology (ISUP) grade ≥3.

Conclusion

The rectal distension-mediated technique is feasible and well tolerated. Dose escalation to 45 Gy with urethra-sparing results in excellent toxicity profiles and PSA relapse rates similar to those reported by other dose-escalated regimens. The existence of intraprostatic recurrences in patients with high-risk features confirms the notion of a high α/β ratio in these phenotypes resulting in diminished effectiveness with hypofractionated dose escalation.

Treatment Strategies for High-Risk Localized and Locally Advanced and Oligometastatic Prostate Cancer

Simple Summary

The definitions of locally advanced and oligometastatic prostate cancer are ambiguous, and there are no standard treatments for these. Although multidisciplinary treatment combining systemic and local treatment may be effective, there are many unresolved issues such as the choice of local treatment, use of new endocrine agents and chemotherapy, and selection of optimal patients. The present article discusses the definitions, diagnoses, and treatment of very high-risk prostate cancer and oligometastatic prostate cancer.

Abstract

Despite the significant advances in the treatment of high-risk prostate cancer, patients with very high-risk features such as being locally advanced (clinical stage T3–4 or minimal nodal involvement), having a high Gleason pattern, or with oligometastasis may still have a poor prognosis despite aggressive treatment. Multidisciplinary treatment with both local and systemic therapies is thought to be effective, however, unfortunately, there is still no standard treatment. However, in recent years, local definitive therapy using a combination of radiotherapy and androgen deprivation is being supported by several randomized clinical trials. This study reviews the current literature with a focus on the definition of very high-risk prostate cancer, the role of modern imaging, and its treatment options.

Proton Therapy for Localized Prostate Cancer: Long-Term Results From a Single-Center Experience

PURPOSE

Although proton therapy is controversial, it has been used to treat localized prostate cancer over the past 2 decades. The purpose of this study is to examine the long-term efficacy and toxicity of proton therapy for localized prostate cancer.

METHODS AND MATERIALS

This was a retrospective observational study of 2021 patients from 2003 to 2014 at a single institution. Patients were classified using the risk groups defined by the National Comprehensive Cancer Network guidelines, version 4.2019. Ninety-eight percent of the patients received 74 Gy (relative biological effectiveness) in 37 fractions. Fifty-one and 6% of the patients received neoadjuvant and adjuvant androgen deprivation therapy, respectively. The outcomes were the time of freedom from biochemical relapse and the time to late toxicity by the National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.0. The outcomes were estimated using the Kaplan-Meier method and were analyzed using multivariable Cox proportional hazards models.

RESULTS

The median follow-up period was 84 months (interquartile range, 60-110). The 5- and 10-year freedom from biochemical relapse rates were 100% and 100%, 99% and 88%, 93% and 86%, 90% and 79%, 88% and 68%, and 76% and 63% for the very low, low, favorable intermediate, unfavorable intermediate, high, and very high-risk groups, respectively. Patients with higher risk experienced biochemical relapse after shorter periods. The 5-year rates of grade 2 or higher late genitourinary and gastrointestinal toxicity were 2.2% and 4.0%, respectively. The results of multivariable analyses indicate that younger patients more often experienced biochemical relapse.

CONCLUSIONS

This study demonstrates the favorable biochemical controls of proton therapy even in advanced localized prostate cancer patients with a low incidence of late toxicities, supporting the feasibility of conducting prospective clinical trials. The risk groups defined by the National Comprehensive Cancer Network guidelines, version 4.2019, are useful to classify patients with localized prostate cancer. Our findings might suggest the necessity to develop a treatment strategy that accounts for the patient's age.

A randomised assessment of image guided radiotherapy within a phase 3 trial of conventional or hypofractionated high dose intensity modulated radiotherapy for prostate cancer

BACKGROUND AND PURPOSE

Image-guided radiotherapy (IGRT) improves treatment set-up accuracy and provides the opportunity to reduce target volume margins. We introduced IGRT methods using standard (IGRT-S) or reduced (IGRT-R) margins in a randomised phase 2 substudy within CHHiP trial. We present a pre-planned analysis of the impact of IGRT on dosimetry and acute/late pelvic side effects using gastrointestinal and genitourinary clinician and patient-reported outcomes (PRO) and evaluate efficacy.

MATERIALS AND METHODS

CHHiP is a randomised phase 3, non-inferiority trial for men with localised prostate cancer. 3216 patients were randomly assigned to conventional (74 Gy in 2 Gy/fraction (f) daily) or moderate hypofractionation (60 or 57 Gy in 3 Gy/f daily) between October 2002 and June 2011. The IGRT substudy included a second randomisation assigning to no-IGRT, IGRT-S (standard CTV-PTV margins), or IGRT-R (reduced CTV-PTV margins). Primary substudy endpoint was late RTOG bowel and urinary toxicity at 2 years post-radiotherapy.

RESULTS

Between June 2010 to July 2011, 293 men were recruited from 16 centres. Median follow-up is 56.9(IQR 54.3-60.9) months. Rectal and bladder dose-volume and surface percentages were significantly lower in IGRT-R compared to IGRT-S group; (p < 0.0001). Cumulative proportion with RTOG grade ≥ 2 toxicity reported to 2 years for bowel was 8.3(95% CI 3.2-20.7)%, 8.3(4.7-14.6)% and 5.8(2.6-12.4)% and for urinary 8.4(3.2-20.8)%, 4.6(2.1-9.9)% and 3.9(1.5-9.9)% in no IGRT, IGRT-S and IGRT-R groups respectively. In an exploratory analysis, treatment efficacy appeared similar in all three groups.

CONCLUSION

Introduction of IGRT was feasible in a national randomised trial and IGRT-R produced dosimetric benefits. Overall side effect profiles were acceptable in all groups but lowest with IGRT and reduced margins.

ISRCTN

97182923.

Long-term outcomes analysis of low-dose-rate brachytherapy in clinically T3 high-risk prostate cancer

PURPOSE

The available data demonstrating that superiority of LDR brachytherapy (LDR-BT) boost in high-risk prostate cancer patients under represents patients with extracapsular extension (T3a) and/or seminal vesicle invasion (T3b) have been limited. We report long-term clinical outcomes data for patients with cT3a/b disease receiving LDR-BT.

METHODS AND MATERIALS

Ninety-nine men (median age: 69.4 years) with cT3a/bN0M0 high-risk prostate adenocarcinoma received definitive LDR-BT or LDR-BT boost after external beam radiation therapy (EBRT) at a single institution between 1998 and 2007. About 86% of patients received androgen deprivation therapy. Freedom from biochemical failure (FFBF), prostate cancer-specific survival (PCSS), and overall survival (OS) was calculated using the Kaplan-Meier method with the Phoenix definition used as definition of failure. Cox regression analysis was used to compare outcomes between clinical stage, initial PSA, Gleason Score, and percent core positive rate.

RESULTS

With a median followup of 7 years, 7-year rate of FFBF, PCSS, and OS for the entire cohort was 65.2% (±5.6%), 90.1% (±3.6%), and 77.9% (±4.7%), respectively. LDR-BT boost patients achieved a 7-year FFBF rate of 73.5 (±6.5%). No significant difference in outcomes was present between T3a or T3b disease, Gleason score, iPSA stratification and percent core positive rates.

CONCLUSIONS

LDR-BT, primarily as a boost in conjunction with ADT and EBRT, is not only feasible, but also highly effective in men with cT3a and cT3b high-risk prostate cancer resulting in excellent biochemical control and survival outcomes. LDR-BT boost implantation of patients should be strongly considered for cT3 patients given the merits of trimodality care.

Dose escalation of external beam radiotherapy for high-risk prostate cancer-Impact of multiple high-risk factor

Objective

To retrospectively investigate the treatment outcomes of external beam radiotherapy with androgen deprivation therapy (ADT) in high-risk prostate cancer in three radiotherapy dose groups.

Methods

Between 1998 and 2013, patients with high-risk prostate cancer underwent three-dimensional conformal radiotherapy or intensity-modulated radiotherapy of 66 Gy, 72 Gy, or 78 Gy with ADT. Prostate-specific antigen (PSA) relapse was defined using the Phoenix definition. PSA relapse-free survival (PRFS) was evaluated in each radiotherapy dose group. Moreover, high-risk patients were divided into H-1 (patients with multiple high-risk factors) and H-2 (patients with a single high-risk factor) as risk subgroups.

Results

Two hundred and eighty-nine patients with a median follow-up period of 77.3 months were analyzed in this study. The median duration of ADT was 10.1 months. Age, Gleason score, T stage, and radiotherapy dose influenced PRFS with statistical significance both in univariate and multivariate analyses. The 4-year PRFS rates in Group-66 Gy, Group-72 Gy and Group-78 Gy were 72.7%, 81.6% and 90.3%, respectively. PRFS rates in the H-1 subgroup differed with statistical significance with an increasing radiotherapy dose having a more favorable PRFS, while PRFS rates in H-2 subgroup did not differ with increase in radiotherapy dose.

Conclusion

Dose escalation for high-risk prostate cancer in combination with ADT improved PRFS. PRFS for patients in the H-1 subgroup was poor, but dose escalation in those patients was beneficial, while dose escalation in the H-2 subgroup was not proven to be effective for improving PRFS.

Multimodal therapy for locally advanced prostate cancer: the roles of radiotherapy, androgen deprivation therapy, and their combination

Locally advanced prostate cancer (LAPC) is defined as histologically proven T3–4 prostatic adenocarcinoma. In this review, we define the individual roles of radiotherapy (RT), short-term (ST-) and long-term (LT-) androgen deprivation therapy (ADT), and their combination in multimodal therapy for LAPC. Despite limitations in comparing the clinical outcomes among published papers, in the present study, a trend of 10-year clinical outcomes was roughly estimated by calculating the average rates weighted by the cohort number. With RT alone, the following rates were estimated: 87% biochemical failure, 34% local failure (LF), 48% distant metastasis (DM), 38% overall survival (OS), and 27% disease-specific mortality (DSM). Those associated with ADT alone were 74% BCF, 54% OS, and 25% DSM, which appeared to be better than those of RT alone. The addition of ADT to RT produced a notable local and systemic effect, regardless of ST- or LT-ADT. The LF rate decreased from 34% with RT alone to 21% with ST-ADT and further to 15% with LT-ADT. The DM and DSM rates also showed a similar trend among RT alone, RT+ST-ADT, and RT+LT-ADT. The combination of RT+LT-ADT resulted in the best long-term clinical outcomes, indicating that both RT and ADT are important parts of multimodal therapy.

Intensity-modulated radiation therapy from 70Gy to 80Gy in prostate cancer: six- year outcomes and predictors of late toxicity

Objective

To report grade ≥2 overall late rectal and urinary toxicities in patients (pts) with prostate cancer treated by intensity-modulated radiotherapy (IMRT) at 3 dose-levels. Identify predictors of radiation toxicity and report biochemical progression free survival (bPFS).

Methods

A total of 277 pts were treated with 70Gy (10.8%), 74Gy (63.9%) and 80 Gy (25.3%) using IMRT without pelvic irradiation were analyzed. Short or long-course androgen deprivation therapy (ADT) was allowed in 46.1% of pts. The toxicity was described using the Common Terminology Criteria for Adverse Events (CTCAE) v4.0 scale. Cox regression models addressed demographics, disease and dosimetry characteristics as potential predictors of late grade ≥2 toxicity after adjusting for other modifying factors.

Results

The median follow-up was 77 months (range 15; 150). There was no grade ≥4 toxicity. The 5-year cumulative rate of grade ≥2 late rectal and urinary toxicities was 6.3% (95% CI = 3.8%; 10.3%) and 25.3% (95% CI = 19.8%; 31.8%) respectively. In multivariate analysis, only the dose (80Gy vs 74 and 70Gy) was found to increase the risk of rectal toxicity (HR = 2.96 [1.07; 8.20]). For pts receiving 74 Gy, International Prostate Symptom Score (IPSS) at baseline ≥8 (HR = 2.40 [1.08; 5.35]) and dose ≥73Gy delivered in more than 2% of bladder (D2%) were found to be predictors of bladder toxicity (HR = 3.29 [1.36; 7.98]). The 5–year biochemical relapse free survival was 81.0% [74.5%; 86.0%] in the entire population, 97.5% [83.5%; 99.6%] in the low risk group, 84.9% [76.7%; 90.3%] in the intermediate risk group and 66.4% [51.8%; 77.4%] in the high-risk group. D’Amico low (HR = 0.09 [0.01; 0.69]) and intermediate risk groups (HR = 0.50 [0.28; 0.88]) as well as PSA nadir ≥0.2 ng/ml (HR = 1.79 [1.01; 3.21]) were predictive of biochemical relapse.

Conclusions

The rate of late rectal toxicity increased with higher doses, while Dmax ≥74Gy, D2% ≥ 73Gy for bladder wall and baseline IPSS ≥8 increased late urinary toxicity.

Moderate Hypofractionation in High-Risk, Organ-Confined Prostate Cancer: Final Results of a Phase III Randomized Trial

Purpose

To report the final results on treatment outcomes of a randomized trial comparing conventional and hypofractionated radiotherapy in high-risk, organ-confined prostate cancer (PCa).

Patients and Methods

This single-institution, randomized clinical trial, conducted from January 2003 to December 2007, enrolled 168 patients with high-risk PCa who were randomly assigned in a 1:1 ratio to conventional (80 Gy in 40 fractions in 8 weeks) or hypofractionated radiotherapy (62 Gy in 20 fractions in 5 weeks) to prostate and seminal vesicles. The primary outcome measure was late toxicity. Additional outcomes were freedom from biochemical failure (FFBF), prostate cancer–specific survival (PCaSS), and overall survival (OS), evaluated on an intention-to-treat basis.

Results

A total of 85 patients were assigned to conventional and 83 to hypofractionated radiotherapy. At a median follow-up of 9 years (interquartile range, 7.5 to 10.1 years), no differences was observed in physician-assessed late gastro intestinal and genitourinary toxicity greater than or equal to grade 2 ( P = .68 and .57, respectively) were found between the two arms. The 10-year FFBF rate was 72% in the hypofractionation group and 65% in the conventional fractionation group ( P = .148). Ten-year OS rates were 75% in the hypofractionation group and 64% in the conventional group, respectively ( P = .22). The same features for 10-year PCaSS were 95% and 88%, respectively ( P = .066). Hypofractionation, pretreatment prostate-specific antigen level, Gleason score, and clinical tumor stage for FFBF, and hypofractionation and Gleason score for PCaSS were significant prognostic variables on the multivariate analysis.

Conclusion

Long-term findings showed that hypofractionated radiotherapy failed the intent of either reducing physician-assessed late toxicity or maintaining the same efficacy. A postrandomization analysis, however, revealed that hypofractionation was a significant prognostic factor for FFBF and PCaSS, when adjusted for clinical prognostic variables.

American Brachytherapy Society Task Group Report: Combination of brachytherapy and external beam radiation for high-risk prostate cancer

PURPOSE

To review outcomes for high-risk prostate cancer treated with combined modality radiation therapy (CMRT) utilizing external beam radiation therapy (EBRT) with a brachytherapy boost.

METHODS AND MATERIALS

The available literature for high-risk prostate cancer treated with combined modality radiation therapy was reviewed and summarized.

RESULTS

At this time, the literature suggests that the majority of high-risk cancers are curable with multimodal treatment. Several large retrospective studies and three prospective randomized trials comparing CMRT to dose-escalated EBRT have demonstrated superior biochemical control with CMRT. Longer followup of the randomized trials will be required to determine if this will translate to a benefit in metastasis-free survival, disease-specific survival, and overall survival. Although greater toxicity has been associated with CMRT compared to EBRT, recent studies suggest that technological advances that allow better definition and sparing of critical adjacent structures as well as increasing experience with brachytherapy have improved implant quality and the toxicity profile of brachytherapy. The role of androgen deprivation therapy is well established in the external beam literature for high-risk disease, but there is controversy regarding the applicability of these data in the setting of dose escalation. At this time, there is not sufficient evidence for the omission of androgen deprivation therapy with dose escalation in this population. Comparisons with surgery remain limited by differences in patient selection, but the evidence would suggest better disease control with CMRT compared to surgery alone.

CONCLUSIONS

Due to a series of technological advances, modern combination series have demonstrated unparalleled rates of disease control in the high-risk population. Given the evidence from recent randomized trials, combination therapy may become the standard of care for high-risk cancers.

The Effectiveness of Intensity Modulated Radiation Therapy versus Three-Dimensional Radiation Therapy in Prostate Cancer: A Meta-Analysis of the Literatures

BACKGROUND AND PURPOSE

Intensity modulated radiation therapy (IMRT) can deliver higher doses with less damage of healthy tissues compared with three-dimensional radiation therapy (3DCRT). However, for the scenarios with better clinical outcomes for IMRT than 3DCRT in prostate cancer, the results remain ambiguous. We performed a meta-analysis to assess whether IMRT can provide better clinical outcomes in comparison with 3DCRT in patients diagnosed with prostate cancer.

MATERIALS AND METHODS

We conducted a meta-analysis of 23 studies (n = 9556) comparing the clinical outcomes, including gastrointestinal (GI) toxicity, genitourinary (GU) toxicity, biochemical controland overall survival (OS).

RESULTS

IMRT was significantly associated with decreased 2-4 grade acute GI toxicity [risk ratio (RR) = 0.59 (95% confidence interval (CI), 0.44, 0.78)], late GI toxicity [RR = 0.54, 95%CI (0.38, 0.78)], late rectal bleeding [RR = 0.48, 95%CI (0.27, 0.85)], and achieved better biochemical control[RR = 1.17, 95%CI (1.08, 1.27)] in comparison with 3DCRT. IMRT and 3DCRT remain the same in regard of grade 2-4 acute rectal toxicity [RR = 1.03, 95%CI (0.45, 2.36)], late GU toxicity [RR = 1.03, 95%CI (0.82, 1.30)] and overall survival [RR = 1.07, 95%CI (0.96, 1.19)], while IMRT slightly increased the morbidity of grade 2-4 acute GU toxicity [RR = 1.08, 95%CI (1.00, 1.17)].

CONCLUSIONS

Although some bias cannot be ignored, IMRT appears to be a better choice for the treatment of prostate cancer when compared with 3DCRT.

Time Course and Accumulated Risk of Severe Urinary Adverse Events After High- Versus Low-Dose-Rate Prostate Brachytherapy With or Without External Beam Radiation Therapy

PURPOSE

Severe urinary adverse events (UAEs) include surgical treatment of urethral stricture, urinary incontinence, and radiation cystitis. We compared the incidence of grade 3 UAEs, according to the Common Terminology Criteria for Adverse Events, after low-dose-rate (LDR) and high-dose-rate (HDR) brachytherapy, as well as after LDR plus external beam radiation therapy (EBRT) and HDR plus EBRT.

METHODS AND MATERIALS

Men aged >65 years with nonmetastatic prostate cancer were identified from the Surveillance, Epidemiology, and End Results-Medicare database who were treated with LDR (n=12,801), HDR (n=685), LDR plus EBRT (n=8518), or HDR plus EBRT (n=2392). The populations were balanced by propensity weighting, and the Kaplan-Meier incidence of severe UAEs was compared. Propensity-weighted Cox proportional hazards models were used to compare the adjusted hazard of UAEs. These UAEs were compared with those in a cohort of men not treated for prostate cancer.

RESULTS

Median follow-up was 4.3 years. At 8 years, the propensity-weighted cumulative UAE incidence was highest after HDR plus EBRT (26.6% [95% confidence interval, 23.8%-29.7%]) and lowest after LDR (15.7% [95% confidence interval, 14.8%-16.6%]). The absolute excess risk over nontreated controls at 8 years was 1.9%, 3.8%, 8.4%, and 12.9% for LDR, HDR, LDR plus EBRT, and HDR plus EBRT, respectively. These represent numbers needed to harm of 53, 26, 12, and 8 persons, respectively. The additional risk of development of a UAE related to treatment for LDR, LDR plus EBRT, and HDR plus EBRT was greatest within the 2 years after treatment and then continued to decline over time. Beyond 4 years, the risk of development of a new severe UAE matched the baseline risk of the control population for all treatments.

CONCLUSIONS

Toxicity differences were observed between LDR and HDR, but the differences did not meet statistical significance. However, combination radiation therapy (either HDR plus EBRT or LDR plus EBRT) increases the risk of severe UAEs compared with HDR alone or LDR alone. The highest increased risk of urinary toxicity occurs within the 2 years after therapy and then declines to an approximately 1% increase in incidence per year.

Oncological outcomes of cryosurgery as primary treatment in T3 prostate cancer: experience of a single centre

OBJECTIVE

To assess the oncological outcomes and determine prognostic factors for overall survival (OS), cancer-specific survival (CSS), and biochemical progression-free survival (BPFS) after cryosurgery for clinical stage T3 prostate cancer.

PATIENTS AND METHODS

Between 2002 and 2007, 75 patients with clinical stage T3 prostate cancer received cryosurgery as primary treatment in our institution. No adjuvant treatment was provided until biochemical failure. After biochemical failure, hormone therapy was administered. Kaplan-Meier analysis was used to calculate the OS, CSS, and BPFS. Cox regression was used to identify factors predictive of survival.

RESULTS

Clinical stage T3a (cT3a) was detected in 60% (45/75) of patients and cT3b detected in 40% (30/75). The 5-year OS, CSS, and BPFS rates were 85.3%, 92.0%, and 48%, respectively. There was a significant difference when comparing the pT3a with the pT3b group for 5-year OS (88.9% vs 80%, P = 0.02) and BPFS (55.6% vs 36.7%, P = 0.01), but there was no difference in CSS (93.3% vs 90%, P = 0.63). Stage, Gleason score, and nadir prostate-specific antigen (PSA) were associated with BPFS, while Gleason score and nadir PSA were the most significant predictors for CSS.

CONCLUSIONS

Cryosurgery can offer good 5-year OS, CSS, and BPFS rates for cT3 prostate cancer, and there was no difference between T3a and T3b for CSS. Gleason score and nadir PSA were the most significant predictors of survival. Further clinical trials are warranted for evaluating the role of cryosurgery for cT3 prostate cancer.

La Radioterapia Nel Trattamento Del Carcinoma Della Prostata: Indicazioni, Evoluzione Tecnologica e Approcci Integrati

Prostate cancer is a heterogeneous, indolent or sometimes aggressive tumor. Treatment options are various and without proved superiority. Radiotherapy (RT) plays a key role in the disease history. Technological evolution with Intensity Modulate Radiation Therapy (IMRT) and Image Guided Radiation Therapy (IGRT) allowed improvement, with significant results on local control and survival. Hypofractionation, Stereotactic Body RT (SBRT) and new brachytherapy approachs are still under investigation, with promising opportunities. Adjuvant vs salvage postoperative RT, hormone association, prophylactic pelvic irradiation are still under debate, but guidelines express overlapping indications.

Multidisciplinary managements will be the future for care optimization, providing the best tool for holistic and informed patients' choice.

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.

Clinical results after high-dose intensity-modulated radiotherapy for high-risk prostate cancer

Purpose. Patients with high-risk prostate cancer (PC) can be treated with high-dose intensity-modulated radiotherapy (IMRT) and long-term androgen deprivation (AD). In this paper we report on (i) late toxicity and (ii) biochemical (bRFS) and clinical relapse-free survival (cRFS) of this combined treatment. Methods. 126 patients with high-risk PC (T3-4 or PSA >20 ng/mL or Gleason 8–10) and ≥24 months of followup were treated with high-dose IMRT and AD. Late toxicity was recorded. Biochemical relapse was defined as PSA nadir +2 ng/mL. Clinical relapse was defined as local failure or metastases. Results. The incidence of late grade 3 gastrointestinal and genitourinary toxicity was 2 and 6%, respectively. Five-year bRFS and cRFS were 73% and 86% respectively. AD was a significant predictor of bRFS (P = 0.001) and cRFS (P = 0.01). Conclusion. High-dose IMRT and AD for high-risk PC offers excellent biochemical and clinical control with low toxicity.

External irradiation with or without long-term androgen suppression for prostate cancer with high metastatic risk: 10-year results of an EORTC randomised study

BACKGROUND

We did a randomised phase 3 trial assessing the benefit of addition of long-term androgen suppression with a luteinising-hormone-releasing hormone (LHRH) agonist to external irradiation in patients with prostate cancer with high metastatic risk. In this report, we present the 10-year results.

METHODS

For this open-label randomised trial, eligible patients were younger than 80 years and had newly diagnosed histologically proven T1-2 prostatic adenocarcinoma with WHO histological grade 3 or T3-4 prostatic adenocarcinoma of any histological grade, and a WHO performance status of 0-2. Patients were randomly assigned (1:1) to receive radiotherapy alone or radiotherapy plus immediate androgen suppression. Treatment allocation was open label and used a minimisation algorithm with institution, clinical stage of the disease, results of pelvic-lymph-node dissection, and irradiation fields extension as minimisation factors. Patients were irradiated externally, once a day, 5 days a week, for 7 weeks to a total dose of 50 Gy to the whole pelvis, with an additional 20 Gy to the prostate and seminal vesicles. The LHRH agonist, goserelin acetate (3·6 mg subcutaneously every 4 weeks), was started on the first day of irradiation and continued for 3 years; cyproterone acetate (50 mg orally three times a day) was given for 1 month starting a week before the first goserelin injection. The primary endpoint was clinical disease-free survival. Analysis was by intention to treat. The trial is registered at ClinicalTrials.gov, number NCT00849082.

FINDINGS

Between May 22, 1987, and Oct 31, 1995, 415 patients were randomly assigned to treatment groups and were included in the analysis (208 radiotherapy alone, 207 combined treatment). Median follow-up was 9·1 years (IQR 5·1-12·6). 10-year clinical disease-free survival was 22·7% (95% CI 16·3-29·7) in the radiotherapy-alone group and 47·7% (39·0-56·0) in the combined treatment group (hazard ratio [HR] 0·42, 95% CI 0·33-0·55, p<0·0001). 10-year overall survival was 39·8% (95% CI 31·9-47·5) in patients receiving radiotherapy alone and 58·1% (49·2-66·0) in those allocated combined treatment (HR 0·60, 95% CI 0·45-0·80, p=0·0004), and 10-year prostate-cancer mortality was 30·4% (95% CI 23·2-37·5) and 10·3% (5·1-15·4), respectively (HR 0·38, 95% CI 0·24-0·60, p<0·0001). No significant difference in cardiovascular mortality was noted between treatment groups both in patients who had cardiovascular problems at study entry (eight of 53 patients in the combined treatment group had a cardiovascular-related cause of death vs 11 of 63 in the radiotherapy group; p=0·60) and in those who did not (14 of 154 vs six of 145; p=0·25). Two fractures were reported in patients allocated combined treatment.

INTERPRETATION

In patients with prostate cancer with high metastatic risk, immediate androgen suppression with an LHRH agonist given during and for 3 years after external irradiation improves 10-year disease-free and overall survival without increasing late cardiovascular toxicity.

Concurrent and adjuvant docetaxel with three-dimensional conformal radiation therapy plus androgen deprivation for high-risk prostate cancer: preliminary results of a multicentre phase II trial

BACKGROUND AND PURPOSE

We evaluate the feasibility of concomitant and adjuvant docetaxel combined with three-dimensional conformal radiotherapy (3D-CRT) and androgen deprivation in high-risk prostate carcinomas.

METHODS

Fifty men with high-risk localized prostate cancer (16), locally advanced (28) or very high-risk prostate cancer (6) were included. Seventy Gy were delivered on prostate and seminal vesicles in 35 fractions, concurrently with weekly docetaxel (20mg/m(2)). Three weeks after the completion of 3D-CRT, docetaxel was given for 3 cycles (60mg/m(2)), every 3 weeks. Patients had to receive LHRH agonist during 3 years.

RESULTS

The intent to treat analysis shows that four patients out of 15 stopped prematurely the chemotherapy due to grade 3-4 acute toxicity. In the per protocol analysis, 46 patients completed a full-dose chemoradiation regimen representing 413 cycles: five patients experienced a grade 3 toxicity, and 15 patients experienced a grade 2 toxicity. With a median follow-up of 54 months, the 5-year clinical disease-free survival was 66.72% and the 5-year survival was 92.15%.

CONCLUSIONS

3D-CRT with androgen deprivation and concurrent weekly docetaxel, followed by three cycles of adjuvant docetaxel may be considered as feasible in high-risk prostate cancer and deserved to be evaluated in a phase III randomized trial.

[Combination of external irradiation and androgen suppression for prostate cancer: facts and questions]

The combination of radiotherapy and androgen suppression with luteinizing hormone releasing hormone agonist is mainly devoted to locally advanced prostate cancer and intermediate or poor risk localized prostate cancer. They are based on phase III randomized trials which have shown that for locally advanced prostate cancer, a four-month complete androgen blockade initiated two months prior radiotherapy and stopped at the completion of radiotherapy increased overall survival in patients with Gleason scores 2-6, meanwhile, an adjuvant long-term androgen suppression (2.5 to three years) improved significantly the overall survival. Complete androgen blockade with a four to six months duration, combined with external irradiation, enhanced the overall survival in patients with intermediate or poor risk localized prostate cancer.

Late toxicity after conformal and intensity-modulated radiation therapy for prostate cancer: impact of previous surgery for benign prostatic hyperplasia

OBJECTIVES

To retrospectively compare late toxicity of conventional-dose three-dimensional conformal radiation therapy (3D-CRT) and high-dose intensity-modulated radiation therapy (IMRT) for prostate cancer.

METHODS

A total of 340 patients with T1-3 prostate cancer were treated with 3D-CRT (n = 228) and IMRT (n = 112). The median follow-up time was 5.9 years and 3.0 years, respectively. The prescription dose was 70 Gy for 3D-CRT and 78 Gy for IMRT. Late gastrointestinal (GI) and genitourinary (GU) toxicities were graded according to the Fox Chase modification of the Radiation Therapy Oncology Group and Late Effects Normal Tissue Task Force criteria.

RESULTS

There was no difference between 3D-CRT and IMRT in the incidence of GI and GU toxicity at 3 years. On multivariate analysis, transurethral resection of prostate/open transvesical prostatectomy (TURP/TVPE) for benign prostatic hyperplasia, carried out before radiotherapy, significantly increased the risk of Grade >or=2 GU toxicity (risk ratio 1.88). Among patients who experienced TURP/TVPE, the 5-year actuarial likelihood of Grade 2-3 urinary incontinence was 23%, compared with 9% for those without prostate surgery (P = 0.01).

CONCLUSIONS

Tolerance of 3D-CRT and IMRT was similar, despite the use of high radiation dose with IMRT. Previous TURP/TVPE increased the risk of GU toxicity.

Image guided dose escalated prostate radiotherapy: still room to improve

BACKGROUND

Prostate radiotherapy (RT) dose escalation has been reported to result in improved biochemical control at the cost of greater late toxicity. We report on the application of 79.8 Gy in 42 fractions of prostate image guided RT (IGRT). The primary objective was to assess 5-year biochemical control and potential prognostic factors by the Phoenix definition. Secondary endpoints included acute and late toxicity by the Radiotherapy Oncology Group (RTOG) scoring scales.

METHODS

From October/2001 and June/2003, 259 men were treated with at least 2-years follow-up. 59 patients had low, 163 intermediate and 37 high risk disease. 43 had adjuvant hormonal therapy (HT), mostly for high- or multiple risk factor intermediate-risk disease (n = 25). They received either 3-dimensional conformal RT (3DCRT, n = 226) or intensity modulated RT (IMRT) including daily on-line IGRT with intraprostatic fiducial markers.

RESULTS

Median follow-up was 67.8 months (range 24.4-84.7). There was no severe (grade 3-4) acute toxicity, and grade 2 acute gastrointestinal (GI) toxicity was unusual (10.1%). The 5-year incidence of grade 2-3 late GI and genitourinary (GU) toxicity was 13.7% and 12.1%, with corresponding grade 3 figures of 3.5% and 2.0% respectively. HT had an association with an increased risk of grade 2-3 late GI toxicity (11% v 21%, p = 0.018). Using the Phoenix definition for biochemical failure, the 5 year-bNED is 88.4%, 76.5% and 77.9% for low, intermediate and high risk patients respectively. On univariate analysis, T-category and Gleason grade correlated with Phoenix bNED (p = 0.006 and 0.039 respectively). Hormonal therapy was not a significant prognostic factor on uni- or multi-variate analysis. Men with positive prostate biopsies following RT had a lower chance of bNED at 5 years (34.4% v 64.3%; p = 0.147).

CONCLUSION

IGRT to 79.8 Gy results in favourable rates of late toxicity compared with published non-IGRT treated cohorts. Future avenues of investigation for toxicity reduction include IMRT, margin reduction, and dose modulation targeted to sites of disease burden. Further work is required to maximize efficacy beyond that achieved through radiation dose escalation alone.

Dose-escalated radiotherapy for high-risk prostate cancer: outcomes in modern era with short-term androgen deprivation therapy

PURPOSE

Randomized data have supported the use of long-term androgen deprivation therapy (ADT) combined with radiotherapy (RT) for men with high-risk prostate cancer. The present study reviewed the outcomes of intermediate- and high-risk men treated with RT and short-term ADT.

MATERIALS AND METHODS

A total of 184 men with any single risk factor of prostate-specific antigen >or=10 ng/mL, clinical Stage T2b or greater, or Gleason score >or=7 were treated with primary external beam RT for nonmetastatic adenocarcinoma of the prostate. The median radiation dose was 74 Gy; 55% were treated with intensity-modulated RT. All patients received ADT for 1 to 6 months (median, 4), consisting of a gonadotropin-releasing hormone analog. Univariate and multivariable analyses were performed for risk factors, including T stage, Gleason score, radiation dose, and prostate-specific antigen level.

RESULTS

With a median follow-up of 51 months, the 4-year freedom from biochemical failure (FFBF) using the nadir plus 2 ng/mL definition was 83% for all patients. Clinical Stage T3 disease was the only variable tested associated with FFBF on univariate (4-year FFBF rate, 46% vs. 87% for Stage T1-T2c disease; p = .0303) and multivariable analysis (hazard ratio, 3.9; p = .0016). On a subset analysis of high-risk patients (National Comprehensive Cancer Network criteria), those with clinical Stage T3 disease (4-year FFBF rate, 46% vs. 80%; p = .0303) and a radiation dose <74 Gy (4-year FFBF rate, 64% vs. 80%) had a poorer outcome on univariate analysis. However, clinical Stage T3 disease and radiation dose were not significant on multivariable analysis, although a statistical multivariable trend was seen for both (p = .0650 and p = .0597, respectively).

CONCLUSION

Short-term ADT and RT might be acceptable for men with intermediate- and high-risk prostate cancer, especially for clinically localized disease treated with doses of >or=74 Gy.

What is the role of androgen deprivation therapy in the treatment of locally advanced prostate cancer?

This Practice Point commentary discusses the paper by Horwitz and colleagues, which reported the long-term results of the RTOG 92-02 trial in which patients with locally advanced, node-negative prostate cancer who were treated with neoadjuvant-concurrent hormone ablation therapy and external beam radiation therapy (70 Gy) were subsequently randomized to receive either no further androgen deprivation or long-term (2-year) goserelin therapy. The results at 10 years confirm biochemical and clinical outcome benefits with the use of long-term androgen deprivation therapy for patients treated with conventional-dose radiotherapy. How these results should best be incorporated into dose-escalated radiotherapeutic approaches remains unclear, however, and this issue requires further investigation.