Stereotactic body radiotherapy for primary prostate cancer: a systematic review

Salvage Radical Prostatectomy after Primary Focal Ablative Therapy: A Systematic Review and Meta-Analysis

CONTEXT

Focal therapy (FT) has been gaining popularity as a treatment option for localized intermediate-risk prostate cancer (PCa) due to the associated lower morbidity compared to whole-gland treatment. However, there is an increased risk of local cancer recurrence requiring subsequent treatment in a small proportion of patients.

OBJECTIVE

To conduct a systematic review and meta-analysis to better describe and analyze patient postoperative, oncologic, and functional outcomes for those who underwent salvage radical prostatectomy (sRP) to manage their primary FT failure.

EVIDENCE ACQUISITION

A systematic review was completed using three databases (PubMed, Embase, and CINAHL) from October to December 2021 to identify data on outcomes in patients who received sRP for cancer recurrence after prior focal treatment.

EVIDENCE SYNTHESIS

12 articles (482 patients) were included. Median time to sRP was 24 months. Median follow-up time was 27 months. A meta-analysis revealed a postoperative complication rate of 15% (95% CI: 0.09, 0.24), with 4.6% meeting criteria for a major complication Clavien (CG) grade ≥3. Severe GU toxicity was seen in 3.6% of the patients, and no patients had severe GI toxicity. Positive surgical margins (PSM) were found in 27% (95% CI: 0.19, 0.37). Biochemical recurrence (BCR) after sRP occurred in 23% (95% CI: 0.17, 0.30), indicating a BCR-free probability of 77% at 2 years. Continence (pad-free) and potency (ability to have penetrative sex) were maintained in 67% (95% CI: 0.53, 0.78) and 37% (95% CI: 0.18, 0.62) at 12 months, respectively.

CONCLUSION

Our evidence shows acceptable complication rates and oncologic outcomes; however, with suboptimal functional outcomes for patients undergoing sRP for recurrent PCa after prior FT. Inferior outcomes were observed for salvage treatment compared to primary radical prostatectomy (pRP). More high-quality studies are needed to better characterize outcomes after this sequence of PCa treatments.

PATIENT SUMMARY

We looked at treatment outcomes and toxicity for men treated with sRP for prior FT failure. We conclude that these patients will have significant detriment to genitourinary function, with outcomes being worse than those for pRP patients.

Is the CyberKnife radiosurgery system effective and safe for patients? An umbrella review of the evidence

Background: The CyberKnife system combines real-time image guidance and a dynamic tracking system to implement frameless radiotherapy. This umbrella review is aimed to evaluate the effectiveness and safety of CyberKnife. Methods: A comprehensive search of health technology assessments and systematic reviews was performed among the Embase, PubMed and other grey databases until July 2020. Treatment outcomes were extracted, and the quality of included studies were assessed using AMSTAR-2. Results: Nineteen studies were eligible. CyberKnife not only had a wide range of applications, long overall survival and great local control, but also had a limited toxicity and good cost-effectiveness compared with other radiotherapy equipment. Conclusion: Despite the relatively low quality of the evidence, our findings can still provide a decision reference for policymakers.

[Focal therapies: An alternative option for low-risk prostate cancer management?]

Recommended options for low-risk prostate cancer treatment are active surveillance, radical treatments or watchful waiting. Focal therapies are currently assessed for low risk prostate cancer treatment. Focal therapies can be performed in research protocols. Oncologic results of these focal treatments are encouraging and show excellent tolerance with few complications. Radical treatments are still possible after focal therapies failure. Focal therapies are a possible solution to over-treatment issue of low risk prostate cancers.

Stereotactic Body Radiotherapy versus Low Dose Rate Brachytherapy for Localised Prostate Cancer: a Cost-Utility Analysis

AIMS

To conduct a cost-utility analysis comparing stereotactic body radiotherapy (SBRT) with low dose rate brachytherapy (LDR-BT) for localised prostate cancer (PCa).

MATERIALS AND METHODS

A decision-analytic Markov model was developed from the healthcare payer perspective to simulate the history of a 66-year-old man with low-risk PCa. The model followed patients yearly over their remaining lifetimes. Health states included 'recurrence-free', 'biochemical recurrence' (BR), 'metastatic' and 'death'. Transition probabilities were based on a retrospective cohort analysis undertaken at our institution. Utilities were derived from the literature. Costs were assigned in 2015 Canadian dollars ($) and reflected Ontario's health system and departmental costs. Outcomes included quality-adjusted life years (QALYs), costs and incremental cost-effectiveness ratios. A willingness-to-pay threshold of $50 000/QALY was used.

RESULTS

SBRT was the dominant strategy with 0.008LYs and 0.029QALYs gained and a reduction in cost of $2615. Under base case conditions, our results were sensitive to the BR probability associated with both strategies. LDR-BT becomes the preferred strategy if the BR with SBRT is 1.3*[baseline BR_SBRT] or if the BR with LDR-BT is 0.76*[baseline BR_LDR-BT]. When assuming the same BR for both strategies, LDR-BT becomes marginally more effective with 0.009QALYs gained at a cost of $272 848/QALY.

CONCLUSIONS

SBRT represents an economically attractive radiation strategy. Further research should be carried out to provide longer-term follow-up and high-quality evidence.

Stereotactic ablative radiotherapy in the treatment of low and intermediate risk prostate cancer: Is there an optimal dose?

PURPOSE

To investigate if stereotactic ablative radiotherapy (SABR) dose is associated with PSA at 3years (PSA_3y) in the treatment of localized prostate cancer and to explore predictors of late genitourinary (GU) toxicity.

MATERIALS AND METHODS

Three prospective trials of SABR were undertaken at our institution: 1) 35Gy/5 fractions/29days; 2) 40Gy/5 fractions/29days; 3) 40Gy/5 fractions/11 or 29days. PSA_3y was analyzed as a continuous variable. Toxicity was defined as the worst new toxicity and assessed using the radiation therapy oncology group (RTOG) late morbidity scheme. Univariate and multivariable regression analyses were conducted to assess the association between dose and PSA_3y, and to explore predictors of late grade 2+ GU toxicity.

RESULTS

Median PSA3y was 0.64 (intraquartile range (IQR): 0.41-1.12) and 0.27 (IQR: 0.12-0.55) ng/mL for patients treated with 35 and 40Gy respectively. A dose of 40Gy was an independent predictor of lower PSA_3y on multivariable analysis (p<0.001). Dose of 40Gy (odds ratio (OR): 16.69, 95%CI: 5.78, 48.20, p<0.001) and higher International Prostate Symptom Score (OR: 1.01, 95%CI: 1.04, 1.16, p=0.001) predicted for late grade 2+ GU toxicity on multivariable logistic regression.

CONCLUSIONS

This analysis suggests that higher SABR dose is associated with lower PSA_3y. Strategies to allow safe SABR dose escalation should be further investigated.

Cyberknife Radioablation of Prostate Cancer – Preliminary Results for 400 Patients

Objectives: To evaluate the tolerance and effectiveness of stereotactic ablative radiotherapy (SABR) applied in the treatment of low and intermediate risk (LR & IR) prostate cancer patients (PCP) and provide an evaluation of the level of risk group impact on treatment results. In addition, androgen deprivation therapy (ADT) usage and prostatic specific antigen (PSA) decline after SABR were assessed. Material and Methods: A total of 400 PCP (213 LR and 187 IR, including T2c) were irradiated with a CyberKnife using fd 7.25 Gy to TD 36.25 Gy. At the start of treatment, 60.3% of patients were undergoing ADT and this gradually decreased to 0% after 38 months. Follow-up was for a median of 15.0 months. Patients were monitored on SABR completion and 1, 4, 8 months later and then subsequently every 6 months. GI (Gastro-Intestinal) and GU (Genito-Urinary) acute and late adverse effects, PSA and ADT usage were evaluated. Results: Failure was noted in 9 patients (2.25%) (5 in LR and 4 in IR groups) - 4 relapses and 5 nodal metastases. No G3/4 late adverse effects (EORTC/RTOG) were observed. Some 0.5% of G3 GU and 0.3% of G3 GI acute reactions were noted respectively on the SABR completion day and one month later. The median of PSA declined 1.5 ng/ml during the first month and 0.6 ng/ml during the next three months. No impact of risk groups on treatment results was found. An impact of ADT on PSA decline was only confirmed for time point interactions. Conclusions: SABR for LR and IR PCP is a safe and effective treatment. The inclusion of T2c patients and the low percentage of IR patient failure permit us the assumption that this procedure could be utilized in the treatment of more advanced cases. The results do not allow clear definition of the impact of ADT on radioablation results in LR and IR+ T2c cases.

First Australian experience of treating localised prostate cancer patients with CyberKnife stereotactic radiotherapy: early PSA response, acute toxicity and quality of life

Introduction

This study is to evaluate biochemical response, acute toxicity and health‐related quality‐of‐life (QOL) outcomes among prostate cancer patients following stereotactic body radiation therapy (SBRT) in the first Australian CyberKnife facility.

Methods

Forty‐five consecutive patients with clinically localised prostate cancer were treated with SBRT using CyberKnife technology and enrolled in this study. Protocol treatment consisted of 36.25 Gy in five fractions. PSA and acute toxicity was assessed at each follow‐up visit and QOL was assessed using the European Organisation for Research and Treatment of Cancer (EORTC) Global Health Status (GHS) C30 and PR25 questionnaires and the Karnofsky Performance Status (KPS). Distance of travel for treatment was recorded.

Results

The median prostate‐specific antigen (PSA) level declined from the initial value of 6.9 ng/mL to 1.5 ng/mL at 6 months and 0.6 ng/mL at 18 months post‐treatment. Results were similar in patients who did not receive hormone therapy. Acute grade 1 gastrointestinal (GI) and genitourinary (GU) toxicities were found in 11.1% and 24.4% of patients respectively. Acute grade 2 GI and GU toxicities were found in 2.2% and 11.1% of patients respectively. There were no grade 3 and grade 4 toxicities. Mean urinary symptom score was 14.8 at baseline, 17.2 at 6 weeks and 18.3 at 6 months (P > 0.05). Mean bowel symptom score was 2.7 at baseline, 4.2 at 6 weeks and 6.3 at 6 months (P > 0.05). The mean GHS score improved from 81.3 at baseline to 82.4 at 6 weeks, and was 75.6 at 6 months (P > 0.05, not significant). Compared to baseline KPS, there was a significant mean decrease from baseline of 96.7 to 93.3 at the 6‐week follow‐up (P = 0.0043), which then recovered to 94.3 at the 6‐month follow‐up (P = 0.1387).

Conclusions

Early results show promising PSA response. Acute toxicity seemed comparable to results from conventionally fractionated radiotherapy and to international prostate SBRT studies. EORTC PR25 and C30 scores did not reveal any significant change from baseline, and although there was a decrease in KPS, the absolute decrease was small.

Hypofractionated image guided radiation therapy followed by prostate seed implant boost for men with newly diagnosed intermediate and high risk adenocarcinoma of the prostate: Preliminary results of a phase 2 prospective study

PURPOSE

A phase 2 protocol was designed and implemented to assess the toxicity and efficacy of hypofractionated image guided intensity modulated radiation therapy (IG-IMRT) combined with low-dose rate 103Pd prostate seed implant for treatment of localized intermediate- and high-risk adenocarcinoma of the prostate.

METHODS AND MATERIALS

This is a report of an interim analysis on 24 patients enrolled on an institutional review board-approved phase 2 single-institution study of patients with intermediate- and high-risk adenocarcinoma of the prostate. The median pretreatment prostate-specific antigen level was 8.15 ng/mL. The median Gleason score was 4 + 3 = 7 (range, 3 + 4 = 7 - 4 + 4 = 8), and the median T stage was T2a. Of the 24 patients, 4 (17%) were high-risk patients as defined by the National Comprehensive Cancer Network criteria, version 2016. The treatment consisted of 2465 cGy in 493 cGy/fraction of IG-IMRT to the prostate and seminal vesicles. This was followed by a 103Pd transperineal prostate implant boost (prescribed dose to 90% of the prostate volume of 100 Gy) using intraoperative planning. Five patients received neoadjuvant, concurrent, and adjuvant androgen deprivation therapy.

RESULTS

The median follow-up was 18 months (range, 1-42 months). The median nadir prostate-specific antigen was 0.5 ng/mL and time to nadir was 16 months. There was 1 biochemical failure associated with distant metastatic disease without local failure. Toxicity (acute or late) higher than grade 3 was not observed. There was a single instance of late grade 3 genitourinary toxicity secondary to hematuria 2 years and 7 months after radiation treatment. There were no other grade 3 gastrointestinal or genitourinary toxicities.

CONCLUSIONS

Early results on the toxicity and efficacy of the combination of hypofractionated IG-IMRT and low-dose-rate brachytherapy boost are favorable. Longer follow-up is needed to confirm safety and effectiveness.

Use, complications, and costs of stereotactic body radiotherapy for localized prostate cancer

BACKGROUND

Stereotactic body radiotherapy (SBRT) for localized prostate cancer has potential advantages over traditional radiotherapies. Herein, the authors compared national trends in use, complications, and costs of SBRT with those of traditional radiotherapies.

METHODS

The authors identified men who underwent SBRT, intensity-modulated radiotherapy (IMRT), brachytherapy, and proton beam therapy as primary treatment of prostate cancer between 2004 and 2011 from Surveillance, Epidemiology, and End Results Program (SEER)-Medicare linked data. Temporal trend of therapy use was assessed using the Cochran-Armitage test. Two-year outcomes were compared using the chi-square test. Median treatment costs were compared using the Kruskal-Wallis test.

RESULTS

A total of 542 men received SBRT, 9647 received brachytherapy, 23,408 received IMRT, and 800 men were treated with proton beam therapy. There was a significant increase in the use of SBRT and proton beam therapy (P<.001), whereas brachytherapy use decreased (P<.001). A higher percentage of patients treated with SBRT and brachytherapy had low-grade cancer (Gleason score ≤ 6 vs ≥ 7) compared with individuals treated with IMRT and proton beam therapy (54.0% and 64.2% vs 35.2% and 49.6%, respectively; P<.001). SBRT compared with brachytherapy and IMRT was associated with equivalent gastrointestinal toxicity but more erectile dysfunction at 2-year follow-up (P<.001). SBRT was associated with more urinary incontinence compared with IMRT and proton beam therapy but less compared with brachytherapy (P<.001, respectively). The median cost of SBRT was $27,145 compared with $17,183 for brachytherapy, $37,090 for IMRT, and $54,706 for proton beam therapy (P<.001).

CONCLUSIONS

The use of SBRT and proton beam therapy for localized prostate cancer has increased over time. Despite men of lower disease stage undergoing SBRT, SBRT was found to be associated with greater toxicity but lower health care costs compared with IMRT and proton beam therapy. Cancer 2016;122:2496-504. © 2016 American Cancer Society.

CyberKnife-based prostate cancer patient radioablation - early results of irradiation in 200 patients

INTRODUCTION

Prostrate cancer (PC) is one of the most common malignancies and is frequently treated with an 8-week course of radiotherapy. CyberKnife (CK) based radioablation enables completion of therapy within 5-9 days. The aim of this study is an evaluation of the effectiveness and tolerance of CyberKnife-based radioablation in prostate cancer patients.

MATERIAL AND METHODS

200 PC patients (94 low risk [LR], 106 intermediate risk [IR]) underwent CK irradiation every other day (fraction dose [fd] 7.25 Gy, total dose [TD] 36.25 Gy, time 9 days). PSA varied from 1.1 to 19.5 (median 7.7) and T stage from T1c to T2c. The percentage of patients with Androgen Deprivation Therapy (ADT), GI (gastrointestinal) and GU (genitourinary) toxicity (EORTC/RTOG scale), and PSA were checked at 1, 4 and 8 months, and thereafter every 6 months - up to a total of 26 months - post-treatment.

RESULTS

The percentage of patients without ADT increased from 47.5% to 94.1% after 26 months. The maximum percentage of acute G3 adverse effects was 0.6% for GI, 1% for GU and G2 - 2.1% for GI and 8.5% for GU. No late G3 toxicity was observed. The maximum percentage of late G2 toxicity was 0.7% for GI and 3.4% for GU. Median PSA decreased from 7.7 to 0.1 ng/ml during FU. One patient relapsed and was treated with salvage brachytherapy.

CONCLUSIONS

We conclude that CK-based radioablation in low and intermediate risk PC patients is an effective treatment modality enabling OTT reduction and presents a very low percentage of adverse effects.

Stereotactic body radiotherapy for the treatment of medically inoperable primary renal cell carcinoma: Current evidence and future directions

The incidence of renal cell carcinoma (RCC) is steadily rising due to an aging population and more frequent imaging of the abdomen for other medical conditions. While surgery remains the standard of care treatment for localized disease, many patients are unfit due to their advanced age and medical comorbidities. In these patients, an active surveillance strategy or ablative therapies, including radiofrequency/microwave ablation or cryotherapy, can be offered. Such options have limitations particularly with fast growing, or larger tumors. A promising ablative therapy option to consider is stereo-tactic body radiotherapy (SBRT). SBRT refers to high dose, focally ablative radiation delivered in a short time (3-5 fractions), and is safe and effective in many other cancer sites, including lung, liver and spine. SBRT offers potential advantages in the primary kidney cancer setting due to its ablative dosing (overcoming the notion of "radio-resistance"), short treatment duration (important in an elderly population), low toxicity profile (enabling SBRT to treat larger RCCs than other ablative modalities), and non-invasiveness. To date, there is limited long-term prospective data on the outcomes of SBRT in primary RCC. However, early evidence is intriguing with respect to excellent local control and low toxicity; however, most studies vary in terms of technique and radiation dosing used. Well-designed prospective cohort studies with clearly defined and standardized techniques, dosing, follow-up, and integration of quality of life outcomes will be essential to further establish the role of SBRT in management of inoperable, localized RCC.

Stereotactic Ablative Radiotherapy with CyberKnife in the Treatment of Locally Advanced Prostate Cancer: Preliminary Results

Aims and Background

Recent clinical reports of stereotactic ablative radiotherapy (SABR) in the treatment of low-risk prostate cancer have been encouraging. Our study evaluates the efficacy and safety of SABR using the CyberKnife system for treating intermediate- to very-high-risk prostate cancer.

Methods and Study Design

Between May 2010 and June 2013, 31 patients (15 intermediate risk, 14 high risk, and 2 very high risk) without pelvic lymph node metastasis were enrolled retrospectively. The treatment consisted of 37.5 Gy in 5 fractions over 1-2 weeks using CyberKnife SABR. Twenty-five patients (81%) received androgen deprivation therapy (ADT). Biochemical failure was defined using the nadir + 2 criterion. Toxicity was assessed with the Common Terminology Criteria of Adverse Events (version 4).

Results

The median follow-up was 36 months (range 7-58 months). The median pretreatment prostate-­pecific antigen (PSA) was 13.5 ng/mL (range 4.5-124.0 ng/mL). The median PSA decreased to 0.09 ng/mL (range <0.04-5.38 ng/mL) and 0.12 ng/mL (range <0.04-2.63 ng/mL) at 6 months and 12 months after SABR, respectively. The 3-year biochemical relapse-free survival was 90.2% for all patients, 100% for the intermediate-risk patients, and 82% for the high- and very-high-risk patients (p = 0.186). No patient experienced ≥ grade 3 toxicity. There were 7 acute and 5 late grade 2 genitourinary toxicities and 1 acute and no late grade 2 gastrointestinal toxicity.

Conclusions

Our preliminary results support that CyberKnife SABR with ADT is safe and feasible in patients with intermediate- to high-risk prostate cancer. A further large-scale clinical trial with longer follow-up is warranted.