Escalated-dose versus standard-dose conformal radiotherapy in prostate cancer: first results from the MRC RT01 randomised controlled trial

Older Age, Early Symptoms and Physical Function are Associated with the Severity of Late Symptom Clusters for Men Undergoing Radiotherapy for Prostate Cancer

AIMS

To identify symptom clusters and predisposing factors associated with long-term symptoms and health-related quality of life after radiotherapy in men with prostate cancer.

MATERIALS AND METHODS

Patient-reported outcomes (PROs) data from the Medical Research Council RT01 radiotherapy with neoadjuvant androgen deprivation therapy trial of 843 patients were used. PROs were collected over 5 years with the University of California, Los Angeles Prostate Cancer Index (UCLA-PCI) and the 36 item Short-Form Health Survey (SF-36). Symptom clusters were explored using hierarchical cluster analysis. The association of treatment dose, baseline patient characteristics and early symptom clusters with the change in severity of PROs over 3 years was investigated with multivariate linear mixed effects models.

RESULTS

Seven symptom clusters of three or more symptoms were identified. The clusters were stable over time. The longitudinal profiles of symptom clusters showed the onset of acute symptoms during treatment for all symptom clusters and significant recovery by 6 months. Some clusters, such as physical health and sexual function, were adversely affected more than others by androgen deprivation therapy, and were less likely to return to pretreatment levels over time. Older age was significantly associated with decreased long-term physical function, physical health and sexual function (P < 0.001). Both baseline and acute symptom clusters were significant antecedents for impaired function and health-related quality of life at 3 years.

CONCLUSIONS

Men with poorer physical function and health before or during treatment were more likely to report poorer PROs at year 3. Early assessment using PROs and lifestyle interventions should be used to identify those with higher needs and provide targeted rehabilitation and symptom management.

Intensity-modulated radiotherapy for prostate cancer

Radiation therapy (RT) is a curative treatment modality for localized prostate cancer. Over the past two decades, advances in technology and imaging have considerably changed RT in prostate cancer treatment. Treatment has evolved from 2-dimensional (2D) planning using X-ray fields based on pelvic bony landmarks to 3-dimensional (3D) conformal RT (CRT) which uses computed tomography (CT) based planning. Despite improvements with 3D-CRT, dose distributions often remained suboptimal with portions of the rectum and bladder receiving unacceptably high doses. In more recent years, intensity-modulated radiation therapy (IMRT) has become the standard of care to deliver external beam RT. IMRT uses multiple radiation beams of different shapes and intensities delivered from a wide range of angles to ‘paint’ the radiation dose onto the tumor. IMRT allows for a higher dose of radiation to be delivered to the prostate while reducing dose to surrounding organs. Multiple clinical trials have demonstrated improved cancer outcomes with dose escalation, but toxicities using 3D-CRT and escalated doses have been problematic. IMRT is a method to deliver dose escalated RT with more conformal dose distributions than 3D-CRT and has been associated with improved toxicity profiles. IMRT also appears to be the safest method to deliver hypofractionated RT and pelvic lymph node radiation. The purpose of this review is to summarize the technical aspects of IMRT planning and delivery, and to review the literature supporting the use of IMRT for prostate cancer.

Two-years Postradiotherapy Biopsies: Lessons from MRC RT01 Trial

BACKGROUND

The importance of 2-yr postradiotherapy prostate biopsy status remains uncertain.

OBJECTIVE

To assess the value of 2 year post treatment biopsies in a randomised trial of radiotherapy dose escalation.

DESIGN, SETTING, AND PARTICIPANTS

Between 1998 and 2001, 843 men with localised prostate cancer were randomised to receive either control-64Gy or escalated-74Gy conformal radiotherapy (CFRT) in the MRC RT01 trial in combination with 3-6-mo neoadjuvant androgen deprivation therapy. Prostate biopsies were planned at 2 yr from start of CFRT in suitable men.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Prostate biopsy results and prostate-specific antigen (PSA) levels performed at 2 yr post-CFRT were evaluated with long-term biochemical progression free survival (bPFS) and overall survival. Outcome measures were timed from the 2-yr biopsy using a landmark approach.

RESULTS AND LIMITATIONS

A 2-yr biopsy was performed in 312/843 patients. One hundred and seventy-seven patients were included in the per-protocol group with median follow-up of 7.8 yr from biopsy. Median PSA at biopsy was 0.5ng/ml. Sixty-four bPFS events were reported: 46/145 (32%) in patients with negative, 6/18 (33%) suspicious, and 12/14 (86%) positive biopsies. A positive biopsy was prognostic of worse bPFS, going forward, compared with negative and suspicious biopsies, hazard ratio (HR)=4.81 (95% confidence interval [CI]: 2.50-9.26, p<0.001). The estimate for survival was HR=1.58 (95% CI: 0.52-4.78, p=0.42). PSA values at 2 yr between 1.01ng/ml and 2.09ng/ml were also associated with subsequent PSA failures (HR=2.71, 95% CI: 1.98-3.71), bPFS events (HR=2.45, 95% CI: 1.81-3.32), and prostate cancer-specific survival (HR=2.87, 95% CI: 1.08-7.64) compared with PSA ≤1.0ng/ml.

CONCLUSIONS

Two-year postradiotherapy prostate biopsies have limited value in patients with PSA control but both positive biopsy and higher PSA status are strongly associated with future bPFS events. A policy of selected biopsy may provide an opportunity for early salvage interventions.

PATIENT SUMMARY

Routine 2-yr postradiotherapy biopsy is not recommended but can be considered in selected patients with unfavourable post-treatment prostate-specific antigen levels who are suitable for early salvage treatments.

Multicenter Trial of Stereotactic Body Radiation Therapy for Low- and Intermediate-Risk Prostate Cancer: Survival and Toxicity Endpoints

PURPOSE

The radiobiology of prostate cancer may favor the extreme hypofractionation inherent in stereotactic body radiation therapy (SBRT); however, data from a large multicenter study are lacking. We therefore examined the hypothesis that dose-escalated SBRT can be safely administered across multiple institutions, with favorable 5-year disease-free survival (DFS) rates compared with historical controls.

METHODS AND MATERIALS

Twenty-one centers enrolled 309 patients with prostate adenocarcinoma: 172 with low-risk (LR) and 137 with intermediate-risk (IR) disease. All were treated with a non-coplanar robotic SBRT platform using real-time tracking of implanted fiducials. The prostate was prescribed 40 Gy in 5 fractions of 8 Gy. We assessed toxicities using Common Terminology Criteria for Adverse Events (CTCAE) version 3 and biochemical failure using the "nadir + 2" definition. The study population yielded 90% power to identify excessive (>10%) rates of grade ≥3 genitourinary (GU) or gastrointestinal toxicities and, in the LR group, 80% power to show superiority in DFS over a 93% historical comparison rate.

RESULTS

At a median follow-up of 61 months, 2 LR patients (1.2%) and 2 IR patients (1.5%) experienced grade 3 GU toxicities, far below the 10% toxicity rate deemed excessive (upper limits of 95% confidence interval, 3.5% and 4.3%, respectively). No grade 4 or 5 toxicities occurred. All grade 3 toxicities were GU, occurring 11 to 51 months after treatment. For the entire group, the actuarial 5-year overall survival rate was 95.6% and the DFS rate was 97.1%. The 5-year DFS rate was 97.3% for LR patients (superior to the 93% DFS rate for historical controls; P = .0008; lower limit of 95% confidence interval, 94.6%) and 97.1% for IR patients.

CONCLUSIONS

Dose-escalated prostate SBRT was administered with minimal toxicity in this multi-institutional study. Relapse rates compared favorably with historical controls. SBRT is a suitable option for LR and IR prostate cancer.

PSMA-PET based radiotherapy: a review of initial experiences, survey on current practice and future perspectives

⁶⁸Gallium prostate specific membrane antigen (PSMA) ligand positron emission tomography (PET) is an increasingly used imaging modality in prostate cancer, especially in cases of tumor recurrence after curative intended therapy. Owed to the novelty of the PSMA-targeting tracers, clinical evidence on the value of PSMA-PET is moderate but rapidly increasing. State of the art imaging is pivotal for radiotherapy treatment planning as it may affect dose prescription, target delineation and use of concomitant therapy.

This review summarizes the evidence on PSMA-PET imaging from a radiation oncologist’s point of view. Additionally a short survey containing twelve examples of patients and 6 additional questions was performed in seven mayor academic centers with experience in PSMA ligand imaging and the findings are reported here.

Dose painting of prostate cancer based on Gleason score correlations with apparent diffusion coefficients

BACKGROUND

Gleason scores for prostate cancer correlates with an increased recurrence risk after radiotherapy (RT). Furthermore, higher Gleason scores correlates with decreasing apparent diffusion coefficient (ADC) data from diffusion weighted MRI (DWI-MRI). Based on these observations, we present a formalism for dose painting prescriptions of prostate volumes based on ADC images mapped to Gleason score driven dose-responses.

METHODS

The Gleason score driven dose-responses were derived from a learning data set consisting of pre-RT biopsy data and post-RT outcomes for 122 patients treated with a homogeneous dose to the prostate. For a test data set of 18 prostate cancer patients with pre-RT ADC images, we mapped the ADC data to the Gleason driven dose-responses by using probability distributions constructed from published Gleason score correlations with ADC data. We used the Gleason driven dose-responses to optimize dose painting prescriptions that maximize the tumor control probability (TCP) with equal average dose as for the learning sets homogeneous treatment dose.

RESULTS

The dose painting prescriptions increased the estimated TCP compared to the homogeneous dose by 0-51% for the learning set and by 4-30% for the test set. The potential for individual TCP gains with dose painting correlated with increasing Gleason score spread and larger prostate volumes. The TCP gains were also found to be larger for patients with a low expected TCP for the homogeneous dose prescription.

CONCLUSIONS

We have from retrospective treatment data demonstrated a formalism that yield ADC driven dose painting prescriptions for prostate volumes that potentially can yield significant TCP increases without increasing dose burdens as compared to a homogeneous treatment dose. This motivates further development of the approach to consider more accurate ADC to Gleason mappings, issues with delivery robustness of heterogeneous dose distributions, and patient selection criteria for design of clinical trials.

Prognostic impact of nodal relapse in definitive prostate-only irradiation

BACKGROUND

Whole pelvic irradiation in prostate cancer patients might prevent metastatic spread of cancer cells through lymphatic drainages in patients eligible for definitive radiotherapy, but its use has declined in the last decades in favor of prostate-only irradiation (POI). The aim of our study is to assess the incidence of pelvic lymph nodal relapse and outcome in prostate cancer patients receiving POI.

MATERIALS AND METHODS

Data from 207 consecutive patients were collected. Clinical and treatment variables were collected. Biochemical relapse-free survival (BRFS), pelvic nodal relapse-free survival (PNRFS), distant metastasis-free survival (DMFS), disease-specific survival (DSS) and overall survival (OS) were calculated; analysis of prognostic variables was performed.

RESULTS

Five-year BRFS, PNRFS, DMFS, DSS and OS were, respectively, 90, 98, 96, 97 and 91%. On multivariate analysis, independent negative predictors of BRFS were Gleason score ≥ 7 (HR: 3.25) and PSA nadir ≥ 0.08 (HR: 4.86). Pelvic nodal relapse was not correlated to impaired outcome.

CONCLUSIONS

Lymph nodal pelvic relapse occurs in 2% of patients at 5 years and does not correlate with impaired outcome, suggesting the lack of theoretical benefit of a prophylactic nodal irradiation. Tumor biology and response to treatment are the main determinants of outcome.

Image-guided radiotherapy reduces the risk of under-dosing high-risk prostate cancer extra-capsular disease and improves biochemical control

BACKGROUND

To determine if reduced dose delivery uncertainty is associated with daily image-guidance (IG) and Prostate Specific Antigen Relapse Free Survival (PRFS) in intensity-modulated radiotherapy (IMRT) of high-risk prostate cancer (PCa).

METHODS

Planning data for consecutive PCa patients treated with IMRT (n = 67) and IG-IMRT (n = 35) was retrieved. Using computer simulations of setup errors, we estimated the patient-specific uncertainty in accumulated treatment dose distributions for the prostate and for posterolateral aspects of the gland that are at highest risk for extra-capsular disease. Multivariate Cox regression for PRFS considering Gleason score, T-stage, pre-treatment PSA, number of elevated clinical risk factors (T2c+, GS7+ and PSA10+), nomogram-predicted risk of extra-capsular disease (ECD), and dose metrics was performed.

RESULTS

For IMRT vs. IG-IMRT, plan dosimetry values were similar, but simulations revealed uncertainty in delivered dose external to the prostate was significantly different, due to positioning uncertainties. A patient-specific interaction term of the risk of ECD and risk of low dose to the ECD (p = 0.005), and the number of elevated clinical risk factors (p = 0.008), correlate with reduced PRFS.

CONCLUSIONS

Improvements in PSA outcomes for high-risk PCa using IG-IMRT vs. IMRT without IG may be due to improved dosimetry for ECD.

Impact of Radiation Therapy Dose Escalation on Prostate Cancer Outcomes and Toxicities

OBJECTIVES

Freedom from biochemical failure (FFBF) is a common primary outcome of randomized-controlled trials of prostate cancer (PCa). We aimed to determine how increasing the PCa biologically equivalent dose (BED) of external radiation therapy (RT) is correlated with FFBF and overall patient outcomes: overall survival (OS), distant metastasis (DM), and cancer-specific mortality (CSM); as well as genitourinary (GU), and gastrointestinal toxicities.

MATERIALS AND METHODS

We performed a meta-analysis of 6884 PCa patients from 12 randomized-controlled trials of external beam RT. Mixed effects regression models were used to estimate weighted linear relationships between BED and observed percentages of 5- and 10-year outcomes. For toxicities, a subset analysis of using 3-dimensional conformal RT (3D-CRT) versus intensity-modulated RT (IMRT) was performed.

RESULTS

Increasing BED correlated with improved FFBF: 10-year absolute improvement of 9.6% and 7.2% for low-risk and intermediate-risk patients, respectively (P<0.05); but not with improvement of OS, DM, or CSM at either time point. BED escalation was not correlated with increased acute toxicities; it was correlated with increased late gastrointestinal toxicities in patients treated with 3D-CRT (1.5% increase over BED range, P<0.01). IMRT patients had significantly fewer late toxicities, despite being treated at higher BED.

CONCLUSIONS

RT BED escalation has resulted in significantly improved PCa FFBF at up to 10 years; but not with improvement in OS, DM, or CSM. Thus, FFBF is a poor surrogate of overall patient outcomes for trials of RT. Late toxicities were less frequent with IMRT than with 3D-CRT, even at higher BED.

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.

Image-Guided Stereotactic Body Radiation Therapy for Localized Prostate Cancer

Purpose

We report the results of a retrospective study of stereotactic body radiation therapy (SBRT) using CyberKnife for localized prostate cancer. The study focused on the safety and feasibility of this treatment modality.

Materials and methods

Between October 2002 and December 2007, 44 patients suffering from localized adenocarcinoma of the prostate were treated with SBRT using CyberKnife at the Korea Cancer Center Hospital. The patients were divided into 3 groups: a low-risk group (5 patients), an intermediate-risk group (10 patients), and a high-risk group (29 patients). Five patients received 32 Gy in 4 fractions, 28 patients received 34 Gy in 4 fractions, and 11 patients received 36 Gy in 4 fractions.

Results

The median age of the patients was 69 years (range, 53–79 years) and the median duration of follow-up 40 months (range, 12–78 months). There were 6 acute and 3 late grade 2 urinary toxicities, and 4 acute and 5 late grade 2 rectal toxicities, but there were no grade 3 or higher treatment-related toxicities. The 5-year cause-specific survival rate and progression-free survival rate were both 100%. At last follow-up, the biochemical failure-free rate of the low-risk, intermediate-risk and high-risk patients was 100%, 100% and 90.8%, respectively.

Conclusion

SBRT using CyberKnife for localized prostate cancer is safe and well tolerated. We obtained promising results with 34 Gy in a 4-fraction regimen especially for the high-risk patients. Free full text available at www.tumorionline.it

Radiotherapy and Hormone Treatment in Prostate Cancer

BACKGROUND

Prostate cancer has the highest incidence of any type of cancer in Germany; an estimated 67 000 new diagnoses of prostate cancer will be made in 2016. In the current German S3 guideline for the treatment of prostate cancer, radiotherapy-sometimes in combination with androgen deprivation therapy (ADT)-is one of the two recommended options for treatment with curative intent (the other is radical prostatectomy). There have been many publications on this subject, yet it is still often unclear in routine practice how ADT should be administered, and for how long.

METHODS

This review is based on publications retrieved by a selective literature search, with special attention to controlled trials.

RESULTS

For low risk patients, radiotherapy without ADT is indicated (evidence level 1). Patients with localized prostate cancer and an intermediate risk benefit from radiotherapy combined with a four-to-six-month course of ADT. In this situation, a higher radiation dose might be an effective substitute for ADT (evidence level 1-2). For patients at high risk, radiotherapy combined with long-term hormonal treatment is the standard therapy, as it significantly improves all oncological end points (evidence level 1). For example, in the largest randomized and controlled trial, this form of treatment reduced cancer-specific mortality from 19% to 9% . Higher radiation doses of 66-74 Gy and longer ADT can improve local control at the cost of increased urethral toxicity.

CONCLUSION

Androgen deprivation combined with external beam radiotherapy is a curative standard option for patients with prostate cancer who are at high risk of recurrence. The modern radiotherapeutic techniques that are now available, such as intensity-modulated radiotherapy, enable a further improvement of the risk/benefit ratio.

Stereotactic Body Radiotherapy for Primary Prostate Cancer

Prostate cancer is the most common non-cutaneous cancer in males. There are a number of options for patients with localized early stage disease, including active surveillance for low-risk disease, surgery, brachytherapy, and external beam radiotherapy. Increasingly, external beam radiotherapy, in the form of dose-escalated and moderately hypofractionated regimens, is being utilized in prostate cancer, with randomized evidence to support their use. Stereotactic body radiotherapy, which is a form of extreme hypofractionation, delivered with high precision and conformality typically over 1 to 5 fractions, offers a more contemporary approach with several advantages including being non-invasive, cost-effective, convenient for patients, and potentially improving patient access. In fact, one study has estimated that if half of the patients currently eligible for conventional fractionated radiotherapy in the United States were treated instead with stereotactic body radiotherapy, this would result in a total cost savings of US$250 million per year. There is also a strong radiobiological rationale to support its use, with prostate cancer believed to have a low α/β ratio and therefore being preferentially sensitive to larger fraction sizes. To date, there are no published randomized trials reporting on the comparative efficacy of stereotactic body radiotherapy compared to alternative treatment modalities, although multiple randomized trials are currently accruing. Yet, early results from the randomized phase III study of HYPOfractionated RadioTherapy of intermediate risk localized Prostate Cancer (HYPO-RT-PC) trial, as well as multiple single-arm phase I/II trials, indicate low rates of late adverse effects with this approach. In patients with low- to intermediate-risk disease, excellent biochemical relapse-free survival outcomes have been reported, albeit with relatively short median follow-up times. These promising early results, coupled with the enormous potential cost savings and implications for resource availability, suggest that stereotactic body radiotherapy will take center stage in the treatment of prostate cancer in the years to come.

Outcomes and toxicity from a prospective study of moderately hypofractionated radiation therapy for prostate cancer

Purpose

The purpose of this study is to report the long-term outcomes and toxicity results of a prospective trial of moderately hypofractionated, image guided radiation therapy (RT) for localized prostate cancer.

Methods and materials

Patients were enrolled between December 2006 and February 2012. Patients in group 1 were stage T1-T2b, had a Gleason score (GS) of 2 to 6 or 7 (3 + 4) with only 1 lobe involved, and had prostate-specific antigen levels ≤10 ng/mL. Group 2 patients were stage ≥T2c, had a GS ≥7 (4 + 3), a GS 7 (3 + 4) involving both lobes, or a PSA >10 ng/mL and ≤30 ng/mL. All patients underwent transrectal ultrasound guided fiducial (Visicoil) placement prior to computed tomography/magnetic resonance imaging simulation. Daily cone beam computed tomography with online correction was used. The prescribed dose was 64 Gy in 20 fractions. The primary endpoint was acute and late toxicity. The secondary endpoint was biochemical control.

Results

A total of 40 patients with a median age of 70 years were recruited for the study. Twenty-two patients (55%) were in group 1, and 18 patients (45%) were in group 2. Thirteen patients (32.5%) were classified as low, 26 patients (65%) as intermediate, and 1 patient (2.5%) as high risk per the National Comprehensive Cancer Network criteria. The median follow-up time was 59 months. Five-year biochemical control was 100% and 94.4% for groups 1 and 2, respectively. Thirteen patients (32.5%) developed acute gastrointestinal (GI) toxicities grade ≥2 and 3 (7.5%) developed acute grade 3 GI toxicity. A total of 17 patients (42.5%) developed grade ≥2 acute genitourinary toxicities and 1 (2.5%) developed acute grade 3 dysuria. Two patients (5%) developed late GI toxicities grade ≥2. There was 1 case (2.5%) of grade 4 fistula requiring sigmoid resection. Seven patients (17.5%) developed grade ≥2 late genitourinary toxicities; 2 patients (5%) late grade 3 urinary frequency/urgency.

Conclusions

Moderately hypofractionated RT is effective with favorable toxicity and biochemical control, providing further evidence that increasing daily fractional dose can be safely and effectively delivered with contemporary RT techniques.

Prostate cancer high dose-rate brachytherapy: review of evidence and current perspectives

INTRODUCTION

Patients with intermediate to high risk disease (prostate specific antigen (PSA) ≥ 10, Gleason score ≥ 7, or clinical stage ≥ T2b) suffer from poorer long-term biochemical control (freedom from an increasing prostate specific antigen level) when treated with external beam radiation (EBRT) alone. In order to improve biochemical control while limiting long-term complications, brachytherapy has been incorporated into radiotherapy treatment, either alone or in combination with EBRT.

AREAS COVERED

Current literature regarding the use of high dose-rate (HDR) brachytherapy for localized prostate cancer, including as a boost and monotherapy. The efficacy and toxicities of various approaches are evaluated including comparisons to low dose-rate (LDR) brachytherapy.

EXPERT COMMENTARY

Prostate HDR brachytherapy has higher conformality than EBRT, potentially improving the therapeutic ratio by allowing higher doses per fraction to tumor cells. The improved biochemical control shown in trials have resulted in EBRT plus brachytherapy to be included as a standard treatment option supported by the NCCN and ASCO guidance documents for intermediate to high risk prostate cancer.

Pelvic bone anatomy vs implanted gold seed marker registration for image-guided intensity modulated radiotherapy for prostate carcinoma: Comparative analysis of inter-fraction motion and toxicities

OBJECTIVES

We compared the prostate motion variability and toxicities between patients treated with gold marker registration based IG-IMRT (IG-IMRT-M) and bony landmark registration based IG-IMRT (IG-IMRT-B).

METHODS

T1c-T3b (node negative), intermediate and high risk (non-metastatic) adenocarcinoma of prostate, age ≥18years, Karnofsky Performance Status of ≥70 were included in this retrospective study. The prostate motion variability, acute and late radiation toxicities between the two treatment arms (IG-IMRT-M versus IG-IMRT-B) were compared.

RESULTS

Total of 35 patients (17 for IG-IMRT-M and 18 for IG-IMRT-B) were treated with a median radiotherapy dose of 76 Gray. The prostate variability observed with and without markers in millimeter was 4.1±2.3 vs 3.7±2.1 [Antero-Posterior (A-P); p=0.001], 2.3±1.5 vs 2.1±1.2 [Superior-Inferior (S-I); p=0.095] and 1.1±1.7 vs 0.4±1.4 [Left-Right (L-R); p=0.003]. There was higher acute toxicity in IG-IMRT-B arm compared to IG-IMRT-M arm in terms of grade ≥2 diarrhea [50% vs 11% OR=7.5 (1.3-42.7); p=0.02] and grade ≥2 proctitis [38% vs 5.8%, OR=10.1 (1.09-94.1); p=0.04]. At a median follow up of 36months, the late genitourinary toxicities grade ≥2 [27% vs 0%; p=0.04] were higher in the IG-IMRT-B arm compared to IG-IMRT-M arm.

CONCLUSIONS

IG-IMRT-M detects higher prostate motion variability as compared to IG-IMRT-B, inferring a significant prostate motion inside fixed pelvic bony cavity. The addition of marker based image guidance results in higher precision of prostate localization and lesser acute and late toxicities.

Approach to the Patient with High-Risk Prostate Cancer

Men classified as having high-risk prostate cancer warrant treatment because durable outcomes can be achieved. Judicious use of imaging and considerations of risk factors are essential when caring for men with high-risk disease. Radical prostatectomy, radiation therapy, and androgen deprivation therapy all play pivotal roles in the management of men with high-risk disease, and potentially in men with metastatic disease. The optimal combinations of therapeutic regimens are an evolving area of study and future work looking into therapies for men with high-risk disease will remain critical.

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.

Prostate-Specific Antigen (PSA) Bounce After Dose-Escalated External Beam Radiation Therapy Is an Independent Predictor of PSA Recurrence, Metastasis, and Survival in Prostate Adenocarcinoma Patients

PURPOSE

To evaluate the difference in prostate-specific antigen (PSA) recurrence-free, distant metastasis-free, overall, and cancer-specific survival between PSA bounce (PSA-B) and non-bounce patients treated with dose-escalated external beam radiation therapy (DE-EBRT).

METHODS AND MATERIALS

During 1990-2010, 1898 prostate adenocarcinoma patients were treated with DE-EBRT to ≥75 Gy with ≥5 years follow-up. Patients receiving neoadjuvant/concurrent androgen-deprivation therapy (n=1035) or with fewer than 4 PSA values obtained 6 months or more after post-EBRT completion (n=87) were excluded. The evaluable 776 patients were treated (median, 81.0 Gy). Prostate-specific antigen bounce was defined as a ≥0.2-ng/mL increase above the interval PSA nadir, followed by a decrease to nadir or below. Prostate-specific antigen relapse was defined as post-radiation therapy PSA nadir + 2 ng/mL. Median follow-up was 9.2 years (interquartile range, 6.9-11.3 years).

RESULTS

One hundred twenty-three patients (15.9%) experienced PSA-B after DE-EBRT at a median of 24.6 months (interquartile range, 16.1-38.5 months). On multivariate analysis, younger age (P=.001), lower Gleason score (P=.0003), and higher radiation therapy dose (P=.0002) independently predicted PSA-B. Prostate-specific antigen bounce was independently associated with decreased risk for PSA relapse (hazard ratio [HR] 0.53; 95% confidence interval [CI] 0.33-0.85; P=.008), distant metastatic disease (HR 0.34; 95% CI 0.12-0.94; P=.04), and all-cause mortality (HR 0.53; 95% CI 0.29-0.96; P=.04) on multivariate Cox analysis. Because all 50 prostate cancer-specific deaths in patients without PSA-B were in the non-bounce cohort, competing-risks analysis was not applicable. A nonparametric competing-risks test demonstrated that patients with PSA-B had superior cancer-specific survival compared with patients without PSA-B (P=.004).

CONCLUSIONS

Patients treated with dose-escalated radiation therapy for prostate adenocarcinoma who experience posttreatment PSA-B have improved PSA recurrence-free survival, distant metastasis-free survival, overall survival, and cancer-specific survival outcomes.

Long-term outcomes in patients treated with proton therapy for localized prostate cancer

The aim of this retrospective study was to report long-term clinical outcomes in patients treated with proton therapy (PT) for localized prostate cancer. Between 2001 and 2014, 1375 consecutive patients were treated with PT. Patients were classified into prognostic risk groups based on the National Comprehensive Cancer Network criteria. Freedom from biochemical relapse (FFBR), cancer-specific survival (CSS) and incidence of late gastrointestinal (GI)/genitourinary (GU) toxicities were calculated. Multivariate analysis was performed to identify clinical prognostic factors for FFBR and late toxicities. The median follow-up period was 70 months (range, 4-145 months). In total, 99% of patients received 74 Gy (relative biologic effectiveness [RBE]); 56% of patients received neoadjuvant androgen deprivation therapy. For the low-, intermediate-, high-, and very high-risk groups, 5-year FFBR was 99% (95% confidence intervals [CI], 96-100%), 91% (95% CI, 88-93%), 86% (95% CI, 82-89%), and 66% (95% CI, 53-76%), respectively, and 5-year CSS was 100% (95% CI, 100-100%), 100% (95% CI, 100-100%) , 99% (95% CI, 97-100%), and 95% (95% CI, 94-98%), respectively. Patient age, T classification, Gleason score, prostate-specific antigen, and percentage of positive cores were significant prognostic factors for FFBR. Grade 2 or higher GI and GU toxicities were 3.9% and 2.0%. Patient age was a prognostic factor for both late GI and GU toxicities. This study represents the largest cohort of patients treated with PT for localized prostate cancer, with the longest follow-up to date. Our results demonstrate that the biochemical control of PT is favorable particularly for high- and very high-risk patients with lower late genitourinary toxicity and indicates the necessity of considering patient age in the treatment protocols.

National Population-Based Study Comparing Treatment-Related Toxicity in Men Who Received Intensity Modulated Versus 3-Dimensional Conformal Radical Radiation Therapy for Prostate Cancer

PURPOSE

To compare, in a national population-based study, severe genitourinary (GU) and gastrointestinal (GI) toxicity in patients with prostate cancer who were treated with radical intensity modulated radiation therapy (IMRT) or 3-dimensional conformal radiation therapy (3D-CRT).

METHODS AND MATERIALS

Patients treated with IMRT (n=6933) or 3D-CRT (n=16,289) between January 1, 2010 and December 31, 2013 in the English National Health Service were identified using cancer registry data, the National Radiotherapy Dataset, and Hospital Episodes Statistics, the administrative database of care episodes in National Health Service hospitals. We developed a coding system that identifies severe toxicity (at least grade 3 according to the National Cancer Institute Common Terminology Criteria for Adverse Events scoring system) according to the presence of a procedure and a corresponding diagnostic code in patients' Hospital Episodes Statistics records after radiation therapy. A competing risks regression analysis was used to estimate hazard ratios (HRs), comparing the incidence of severe GI and GU complications after IMRT and 3D-CRT, adjusting for patient, disease, and treatment characteristics.

RESULTS

The use of IMRT, as opposed to 3D-CRT, increased from 3.1% in 2010 to 64.7% in 2013. Patients who received IMRT were less likely than those receiving 3D-CRT to experience severe GI toxicity (4.9 vs 6.5 per 100 person-years; adjusted HR 0.66; 95% confidence interval 0.61-0.72) but had similar levels of GU toxicity (2.3 vs 2.4 per 100 person-years; adjusted HR 0.94; 95% confidence interval 0.84-1.06).

CONCLUSIONS

Prostate cancer patients who received radical radiation therapy using IMRT were less likely to experience severe GI toxicity, and they had similar GU toxicity compared with those who received 3D-CRT. These findings in an unselected "real-world" population support the use of IMRT, but further cost-effectiveness studies are urgently required.

Hospital Quality Factors Influencing the Mobility of Patients for Radical Prostate Cancer Radiation Therapy: A National Population-Based Study

Purpose

To investigate whether patients requiring radiation treatment are prepared to travel to alternative more distant centers in response to hospital choice policies, and the factors that influence this mobility.

Methods and Materials

We present the results of a national cohort study using administrative hospital data for all 44,363 men who were diagnosed with prostate cancer and underwent radical radiation therapy in the English National Health Service between 2010 and 2014. Using geographic information systems, we investigated the extent to which men choose to travel beyond (“bypass”) their nearest radiation therapy center, and we used conditional logistic regression to estimate the effect of hospital and patient characteristics on this mobility.

Results

In all, 20.7% of men (n=9161) bypassed their nearest radiation therapy center. Travel time had a very strong impact on where patients moved to for their treatment, but its effect was smaller for men who were younger, more affluent, and from rural areas (P for interaction always <.001). Men were prepared to travel further to hospitals that offered hypofractionated prostate radiation therapy as their standard schedule (odds ratio 3.19, P<.001), to large-scale radiation therapy units (odds ratio 1.56, P<.001), and to hospitals that were early adopters of intensity modulated radiation therapy (odds ratio 1.37, P<.001).

Conclusions

Men with prostate cancer are prepared to bypass their nearest radiation therapy centers. They are more likely to travel to larger established centers and those that offer innovative technology and more convenient radiation therapy schedules. Indicators that accurately reflect the quality of radiation therapy delivered are needed to guide patients' choices for radiation therapy treatment. In their absence, patient mobility may negatively affect the efficiency and capacity of a regional or national radiation therapy service and offer perverse incentives for technology adoption.

Intermediate-term outcome after PSMA-PET guided high-dose radiotherapy of recurrent high-risk prostate cancer patients

BACKGROUND

By the use of PSMA positron emission tomography (PET) detection of prostate cancer lesions with a high sensitivity and specificity combined with a favorable lesion to background contrast is feasible. Therefore, PSMA-PET is increasingly used for planning of radiotherapy treatment; however, any data on intermediate-term outcome is missing so far.

METHODS

Patients with high-risk or very high risk prostate cancer, referred for salvage radiotherapy (SRT, n = 22) between 2013 and 2015, underwent PSMA-PET prior to therapy. Irradiation was planned on PET data with boost to macroscopic tumors/metastases. Treatment related toxicity was measured using Common Terminology Criteria for Adverse Events (CTCAE, v4.0).

RESULT

Findings in PSMA-PET led to treatment modifications in 77% of SRT patients compared to available CT information. One patient did not receive irradiation due to disseminated disease, the other patients received increased boost doses to macroscopic disease and/or inclusion of additional target volumes. Toxicity was low as only 2 patients reported toxicities > grade 1. With a Median follow-up time of 29 in patients that were not lost to follow-up, prolonged PSA responses below baseline were observed in the majority of patients (14 of 20). In hormone-naïve SRT patients (n = 11), radiotherapy led to prolonged PSA decrease in 8/11 patients, however with 3 of these 8 patients receiving repeated PSMA based irradiation of novel lesions during follow-up.

CONCLUSION

PSMA-PET guided planning of radiotherapy led to change of treatment in the majority of patients. Treatment related toxicity was well tolerated and promising results regarding intermediate-term PSA decrease were observed.

TRIAL REGISTRATION

No trial registration was performed due to retrospective evaluation.

A retrospective study of late adverse events in proton beam therapy for prostate cancer

The efficacy and safety of proton beam therapy (PBT) were retrospectively evaluated in 111 consecutive patients with prostate cancer who underwent definitive PBT between 2008 and 2012. Following exclusion of 18 patients due to treatment suspension, loss to follow-up, and histology, the analysis included 93 patients with a median age of 68 years (range, 49–81 years). A total of 7, 32 and 54 prostate cancer patients were classified as low-, intermediate- and high-risk, respectively, as follows: High-risk, T≥3a or prostate-specific antigen (PSA) ≥20 ng/ml or Gleason Score ≥8; low-risk, T ≤2b and PSA≤10 ng/ml and Gleason Score=6; intermediate-risk, all other combinations. The median initial prostate-specific antigen (PSA) level was 9.75 ng/ml (range, 1.4–100 ng/ml) and the median Gleason score was 7 (range, 6–10). Patients with low-risk disease received 74 GyE (relative biological effectiveness=1.1) in 37 fractions, and those at intermediate or higher risk received 78 GyE in 39 fractions. Complete androgen blockade (CAB) therapy was performed from 6 months prior to PBT for patients with intermediate- or high-risk disease. CAB was continued during PBT and then terminated at the end of PBT for intermediate-risk patients. Patients at high risk continued CAB for 3 years. No combination therapy was used for low-risk patients. All the patients were followed up for >2 years after PBT, and all but one were PSA failure-free. The Common Terminology Criteria for Adverse Events v.4.0 was used to evaluate late adverse events. One patient developed grade 3 non-infectious cystitis and hematuria. Grade 2 urinary frequency was observed in 1 patient, and grade 2 rectal bleeding occurred in 4 patients. Of the 4 patients with grade 2 rectal bleeding, 2 received anticoagulant therapy, but none had diabetes mellitus or another high-risk comorbidity. The median time to occurrence of an adverse event of grade ≥2 was 14 months (range, 3–41 months). Therefore, the present retrospective study revealed that PBT at 78 GyE/39 Fr was well-tolerated and achieved good tumor control in patients with prostate cancer.

A novel CBCT-based method for derivation of CTV-PTV margins for prostate and pelvic lymph nodes treated with stereotactic ablative radiotherapy

BACKGROUND

Traditional CTV-PTV margin recipes are not generally applicable in the situation of stereotactic ablative radiotherapy (SABR) treatments of multiple target volumes with a single isocentre. In this work, we present a novel geometric method of margin derivation based on CBCT-derived anatomical data.

METHODS

Twenty patients with high-risk localized prostate cancer were selected for retrospective review. Individual volumes of interest (prostate, prostate and seminal vesicles and pelvic lymph nodes) were delineated on five representative CBCTs and registered to the planning CT using two registration protocols: bone match or prostate-based soft tissue match. Margins were incrementally expanded around composite CTV structures until 95% overlap was achieved.

RESULTS

CTV-PTV margins of 5.2, 6.5 and 7.6 mm were required for prostate, prostate and seminal vesicles and pelvic lymph nodes respectively using a prostate matching protocol. For the prostate and seminal vesicle structures, margins calculated using our method displayed good agreement with a conventional margin recipe (within ±1.0 mm).

CONCLUSIONS

We have presented an alternative method of CTV-PTV margin derivation that is applicable to SABR treatments with more than one isocentric target. These results have informed an institutional trial of prostate and pelvic nodal SABR in men with high-risk localized prostate cancer.

Symptom clusters for revising scale membership in the analysis of prostate cancer patient reported outcome measures: a secondary data analysis of the Medical Research Council RT01 trial (ISCRTN47772397)

PURPOSE

To investigate the role of symptom clusters in the analysis and utilisation of patient reported outcome measures (PROMs) for data modelling and clinical practice. To compare symptom clusters with scales, and to explore their value in PROMs interpretation and symptom management.

METHODS

A dataset called RT01 (ISCRTN47772397) of 843 prostate cancer patients was used. PROMs were reported with the University of California, Los Angeles Prostate Cancer Index (UCLA-PCI). Symptom clusters were explored with hierarchical cluster analysis (HCA) and average linkage method (correlation > 0.6). The reliability of the Urinary Function Scale was evaluated with Cronbach's Alpha. The strength of the relationship between the items was investigated with Spearman's correlation. Predictive accuracy of the clusters was compared to the scales by receiver operating characteristic (ROC) analysis. Presence of urinary symptoms at 3 years measured with the late effects on normal tissue: subjective, objective, management tool (LENT/SOM) was an endpoint.

RESULTS

Two symptom clusters were identified (urinary cluster and sexual cluster). The grouping of symptom clusters was different than UCLA-PCI Scales. Two items of the urinary function scales ("number of pads" and "urinary leak interfering with sex") were excluded from the urinary cluster. The correlation with the other items in the scale ranged from 0.20 to 0.21 and 0.31 to 0.39, respectively. Cronbach's Alpha showed low correlation of those items with the Urinary Function Scale (0.14-0.36 and 0.33-0.44, respectively). All urinary function scale items were subject to a ceiling effect. Clusters had better predictive accuracy, AUC = 0.70 -0.65, while scales AUC = 0.67-0.61.

CONCLUSION

This study adds to the knowledge on how cluster analysis can be applied for the interpretation and utilisation of PROMs. We conclude that multiple-item scales should be evaluated and that symptom clusters provide a study-specific approach for modelling and interpretation of PROMs.

Heterogeneity in high-risk prostate cancer treated with high-dose radiation therapy and androgen deprivation therapy

Background

Our aim was to assess the heterogeneity of high-risk (HR) prostate cancer managed with high-dose external beam radiotherapy (EBRT) with androgen deprivation therapy (ADT).

Methods

We identified 547 patients who were treated with modern EBRT from 1997 to 2013, of whom 98% received ADT. We analyzed biochemical relapse-free survival (bRFS) and distant metastases-free survival (DMFS).

Results

Median EBRT dose was 74 Gy, and median ADT duration was 8 months. At 5 years, the DMFS was 85%. On multivariate analysis, significant predictors of shorter bRFS were biopsy Gleason score (bGS) of 8 to 10, higher prostate-specific antigen (PSA) level, shorter duration of ADT and lower radiation dose while predictors of shorter DMFS were bGS of 8 to 10, higher PSA level, and lower radiation dose. We identified an unfavorable high-risk (UHR) group of with 2–3 HR factors based on 2015 National Comprehensive Cancer Network (NCCN) criteria and a favorable high-risk (FHR) group, with 1 HR feature. Comparing very-HR prostate cancer, UHR & FHR, 5 year bRFS rates were 58.2%, 66.2%, and 69.2%, and 5 year DMFS rates were 78.4%, 81.2%, and 88.0%.

Conclusion

Patients with multiple HR factors have worse outcome than patients with 1 HR factor. Future studies should account for this heterogeneity in HR prostate cancer.

Reducing rectal injury in men receiving prostate cancer radiation therapy: current perspectives

Dose escalation is now the standard of care for the treatment of prostate cancer with radiation therapy. However, the rectum tends to be the dose-limiting structure when treating prostate cancer, given its close proximity. Early and late toxicities can occur when the rectum receives large doses of radiation therapy. New technologies allow for prevention of these toxicities. In this review, we examine the evidence that supports various dose constraints employed to prevent these rectal injuries from occurring. We also examine the use of intensity-modulated radiation therapy and how this compares to older radiation therapy techniques that allow for further sparing of the rectum during a radiation therapy course. We then review the literature on endorectal balloons and the effects of their daily use throughout a radiation therapy course. Tissue spacers are now being investigated in greater detail; these devices are injected into the rectoprostatic fascia to physically increase the distance between the prostate and the anterior rectal wall. Last, we review the use of systemic drugs, specifically statin medications and antihypertensives, as well as their impact on rectal toxicity.

The Missing Pieces in Reporting of Randomized Controlled Trials of External Beam Radiation Therapy Dose Escalation for Prostate Cancer

Randomized controlled trials (RCTs) are the most rigorous way of determining whether a cause-effect relation exists between treatment and outcome and for assessing the cost-effectiveness of a treatment. For many patients, cancer is a chronic illness; RCTs evaluating treatments for indolent cancers must evolve to facilitate medical decision-making, as "concrete" patient outcomes (eg, survival) will likely be excellent independent of the intervention, and detecting a difference between trial arms may be impossible. In this commentary, we articulate 9 recommendations that we hope future clinical trialists and funding agencies (including those under the National Cancer Institute) will take into consideration when planning RCTs to help guide subsequent interpretation of results and clinical decision making, based on RCTs of external beam radiation therapy dose escalation for the most common indolent cancer in men, that is, prostate cancer. We recommend routinely reporting: (1) race; (2) medical comorbidities; (3) psychiatric comorbidities; (4) insurance status; (5) education; (6) marital status; (7) income; (8) sexual orientation; and (9) facility-related characteristics (eg, number of centers involved, type of facilities, yearly hospital volumes). We discuss how these factors independently affect patient outcomes and toxicities; future clinicians and governing organizations should consider this information to plan RCTs accordingly (to maximize patient accrual and total n), select appropriate endpoints (eg, toxicity, quality of life, sexual function), actively monitor RCTs, and report results so as to identify the optimal treatment among subpopulations.

The impact of comorbidities on the benefits of prolonged androgen ablation in patients with T3-4 prostate cancer treated with external beam radiation therapy

PURPOSE

To determine whether the survival benefit associated with prolonged androgen deprivation therapy (ADT) and radiotherapy (EBRT) varies with baseline estimates of overall survival in cT3-4 prostate cancer patients (PCa).

METHODS AND MATERIALS

In 1997, the BC Cancer Agency adopted as standard a policy of prolonged ADT (>18months) with EBRT for locally advanced PCa. Two cohorts of cT3-T4 PCa treated with EBRT were selected: 1993-1995 (early: N=725) and 1999-2001 (late: N=584). Duration of ADT and baseline prognostic factors (age, clinical stage, grade, presenting PSA, and Charlson index (CCI)) were abstracted from charts. Estimates of 10-year (E10) survival using an age-adjusted CCI were calculated and patients were grouped into low (<60%), medium (60-90%) and high (>90%) E10. In each E10 group, actual overall survivals were compared by era using log rank test.

RESULTS

There were 318 low, 544 medium, and 447 high E10 patients with median follow-up of 11.1years. Gleason grade and T stage were not statistically different between E10 groups. As expected, median age and baseline CCI were higher in lower E10 groups (p<0.0001). Overall survival was higher in the late era, but varied with E10 group: low (43% vs. 49%, p=0.54), medium (55% vs. 64%, p=0.02) and high (66% vs. 77%, p=0.01).

CONCLUSION

The policy of prolonged ADT with EBRT provides a survival benefit that varies with baseline risk of death from other causes. Absolute benefit from ADT is largest in those with medium or high E10.

ACR Appropriateness Criteria for external beam radiation therapy treatment planning for clinically localized prostate cancer, part II of II

PURPOSE

To present the most updated American College of Radiology (ACR) Appropriateness Criteria formed by an expert panel on the appropriate delivery of external beam radiation to manage stage T1 and T2 prostate cancer (in the definitive setting and post-prostatectomy) and to provide clinical variants with expert recommendations based on accompanying Appropriateness Criteria for target volumes and treatment planning.

METHODS AND MATERIALS

The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a panel of multidisciplinary experts. The guideline development and revision process includes an extensive analysis of current medical literature from peer-reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In instances in which evidence is lacking or equivocal, expert opinion may supplement available evidence to recommend imaging or treatment.

RESULTS

The panel summarizes the most recent and relevant literature on the topic, including organ motion and localization methods, image guidance, and delivery techniques (eg, 3-dimensional conformal intensity modulation). The panel presents 7 clinical variants, including (1) a standard case and cases with (2) a distended rectum, (3) a large-volume prostate, (4) bilateral hip implants, (5) inflammatory bowel disease, (6) prior prostatectomy, and (7) a pannus extending into the radiation field. Each case outlines the appropriate techniques for simulation, treatment planning, image guidance, dose, and fractionation. Numerical rating and commentary is given for each treatment approach in each variant.

CONCLUSIONS

External beam radiation is a key component of the curative management of T1 and T2 prostate cancer. By combining the most recent medical literature, these Appropriateness Criteria can aid clinicians in determining the appropriate treatment delivery and personalized approaches for individual patients.

Comparative effectiveness of radical prostatectomy and curative radiotherapy in localized prostate cancer: long-term follow-up

We sought to investigate the long-term outcomes after radical prostatectomy (RP) and external-beam radiation therapy (EBRT) for the treatment of localized prostate cancer in Japanese patients. RP and radiation therapy are curative treatments for localized prostate cancer. However, there is controversy around which treatment is superior in Japanese patients. The aim of our retrospective study was to compare the long-term clinical outcomes of each treatment. We retrospectively evaluated the overall survival (OS), cancer-specific survival (CSS) and biochemical failure-free survival (BFS) for patients who had been diagnosed with localized prostate cancer and treated with RP (n = 248) or conventional 2D or 3D-CRT EBRT (n = 182) between 1995 and 2009. The median OS was superior in the RP group compared with that in EBRT group (P < 0.001), although CSS was comparable for both treatment groups; BFS was superior for the EBRT group compared with that for the RP group (P = 0.04). Univariate analysis identified a prostate-specific antigen count (PSA)of ≥20 vs <20 mg/ml, clinical T-stage of the tumor and Gleason score as predictors for CSS. However, multivariate analysis did not identify a factor for CSS. Subgroup analysis was also performed based on clinical T stage, PSA and Gleason score, but there was no difference in each subgroup between RP and EBRT. Both treatments provided satisfactory clinical outcomes in terms of disease control in localized prostate cancer.

Nomogram to predict rectal toxicity following prostate cancer radiotherapy

BACKGROUND

To identify predictors of acute and late rectal toxicity following prostate cancer radiotherapy (RT), while integrating the potential impact of RT technique, dose escalation, and moderate hypofractionation, thus enabling us to generate a nomogram for individual prediction.

METHODS

In total, 972 patients underwent RT for localized prostate cancer, to a total dose of 70 Gy or 80 Gy, using two different fractionations (2 Gy or 2.5 Gy/day), by means of several RT techniques (3D conformal RT [3DCRT], intensity-modulated RT [IMRT], or image-guided RT [IGRT]). Multivariate analyses were performed to identify predictors of acute and late rectal toxicity. A nomogram was generated based on the logistic regression model used to predict the 3-year rectal toxicity risk, with its accuracy assessed by dividing the cohort into training and validation subgroups.

RESULTS

Mean follow-up for the entire cohort was 62 months, ranging from 6 to 235. The rate of acute Grade ≥2 rectal toxicity was 22.2%, decreasing when combining IMRT and IGRT, compared to 3DCRT (RR = 0.4, 95%CI: 0.3-0.6, p<0.01). The 5-year Grade ≥2 risks for rectal bleeding, urgency/tenesmus, diarrhea, and fecal incontinence were 9.9%, 4.5%, 2.8%, and 0.4%, respectively. The 3-year Grade ≥2 risk for overall rectal toxicity increased with total dose (p<0.01, RR = 1.1, 95%CI: 1.0-1.1) and dose per fraction (2Gy vs. 2.5Gy) (p = 0.03, RR = 3.3, 95%CI: 1.1-10.0), and decreased when combining IMRT and IGRT (RR = 0.50, 95% CI: 0.3-0.8, p<0.01). Based on these three parameters, a nomogram was generated.

CONCLUSIONS

Dose escalation and moderate hypofractionation increase late rectal toxicity. IMRT combined with IGRT markedly decreases acute and late rectal toxicity. Performing combined IMRT and IGRT can thus be envisaged for dose escalation and moderate hypofractionation. Our nomogram predicts the 3-year rectal toxicity risk by integrating total dose, fraction dose, and RT technique.

Survival and Complications Following Surgery and Radiation for Localized Prostate Cancer: An International Collaborative Review

BACKGROUND

Evaluation of treatment options for localized prostate cancer (PCa) remains among the highest priorities for comparative effectiveness research. Surgery and radiotherapy (RT) are the two interventions most commonly used.

OBJECTIVE

To provide a critical narrative review of evidence of the comparative effectiveness and harms of surgery and RT in the treatment of localized PCa.

EVIDENCE ACQUISITION

A collaborative critical narrative review of the literature was conducted.

EVIDENCE SYNTHESIS

Evidence to clearly guide treatment choice in PCa remains insufficient. Randomized trials are underpowered for clinically meaningful endpoints and have demonstrated no difference in overall or PCa-specific survival. Observational studies have consistently demonstrated an absolute survival benefit for men treated with radical prostatectomy, but are limited by selection bias and residual confounding errors. Surgery and RT are associated with comparable health-related quality of life following treatment in three randomized trials. Randomized data regarding urinary, erectile, and bowel function show few long-term (>5 yr) differences, although short-term continence and erectile function were worse following surgery and short-term urinary bother and bowel function were worse following RT. There has been recent recognition of other complications that may significantly affect the life trajectory of those undergoing PCa treatment. Of these, hospitalization, the need for urologic, rectoanal, and other major surgical procedures, and secondary cancers are more common among men treated with RT. Androgen deprivation therapy, frequently co-administered with RT, may additionally contribute to treatment-related morbidity. Technological innovations in surgery and RT have shown inconsistent oncologic and functional benefits.

CONCLUSIONS

Owing to underpowered randomized control studies and the selection biases inherent in observational studies, the question of which treatment provides better PCa control cannot be definitively answered now or in the near future. Complications following PCa treatment are relatively common regardless of treatment approach. These include the commonly identified issues of urinary incontinence and erectile dysfunction, and others including hospitalization and invasive procedures to manage complications and secondary malignancies. Population-based outcome studies, rather than clinical trial data, will be necessary for a comprehensive understanding of the relative benefits and risks of each therapeutic approach.

PATIENT SUMMARY

Surgery and radiotherapy are the most common interventions for men diagnosed with prostate cancer. Comparisons of survival after these treatments are limited by various flaws in the relevant studies. Complications are common regardless of the treatment approach.

Long-Term Results of a Randomized Trial Comparing Iridium Implant Plus External Beam Radiation Therapy With External Beam Radiation Therapy Alone in Node-Negative Locally Advanced Cancer of the Prostate

PURPOSE

To determine the impact on long-term survival from the addition of brachytherapy to external beam radiation therapy (EBRT) in patients with prostate cancer.

METHODS AND MATERIALS

Between 1992 and 1997, 104 men with cT2-3, surgically staged node-negative prostate cancer were randomized to receive either EBRT (40 Gy/20 fractions) with iridium implant (35 Gy/48 hours) or EBRT alone (66 Gy/33 fractions) to the prostate. According to T stage, Gleason score, and prostate-specific antigen level, 60% of patients had high-risk disease. Substantial improvements in biochemical control at 8 years have previously been reported. Additional follow-up was collected on deaths and metastases.

RESULTS

Median follow-up was 14 years. Five patients were lost to follow-up. All other patients have been followed a minimum of 13 years. There have been 75 deaths, including 21 from prostate cancer and 25 from second cancers. No patients developing a second cancer have died from prostate cancer. There was no difference in overall survival between the 2 treatment groups: 34 deaths (67%) in the implant arm and 41 (77%) in the EBRT arm (hazard ratio [HR] 1.00, 95% confidence interval [CI] 0.63-1.59). Similarly, there was no difference in prostate cancer-specific deaths: 9 (18%) patients in the implant arm compared with 12 (23%) in the EBRT arm (HR 0.79, 95% CI 0.34-1.87). There was no statistically significant difference in the number of patients developing metastatic disease: 10 (20%) in the implant arm and 15 (28%) in the EBRT arm (HR 0.70, 95% CI 0.32-1.57). Improvements in biochemical control were maintained (HR 0.53, 95% CI 0.31-0.88).

CONCLUSIONS

Despite a dramatic reduction of biochemical recurrence rates, the addition of iridium implant to EBRT did not translate into improved overall survival or prostate cancer-specific survival.

Hypofractionation for prostate cancer: an update

Recent advances in image guided radiation therapy (IGRT) has prompted much interest in the use of high-dose-per-fraction regimens for prostate cancer. Furthermore, from a radiobiological standpoint, there is increasing evidence that prostate tumors have a relatively low ɑ/β ratio therefore, the use of hypofractionation may potentially offer acceptable tumor control while minimizing late toxicity to critical structures. Areas covered: This expert review explores the current evidence regarding the safety and efficacy of hypofractionated radiotherapy for prostate cancer. A particular emphasis was placed on large, randomized phase III trials as these are most likely to influence clinical practice. The authors discuss the use of both moderate and extreme hypofractionation. Expert commentary: The recent publication of 5-year outcomes from large prospective trials of moderate hypofractionation enhances our confidence that these techniques are both safe and effective. We recommend the fractionation scheme of 60 Gy in 20 fractions as this regimen was not associated with any notable increase in late toxicity. With respect to extreme hypofractionation, mature phase III trials are needed to demonstrate the safety and efficacy of these techniques. For now, the use of radiosurgery should be limited to participation in prospective clinical trials.