Prostate specific antigen five years following stereotactic body radiation therapy (SBRT) for low and intermediate risk prostate cancer: An ablative procedure?

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Background: Our previous work on early PSA kinetics following prostate SBRT showed that an initial rapid and then slow PSA decline may result in very low PSA nadirs. This retrospective study sought to evaluate the PSA nadir 5 years following SBRT for low and intermediate risk prostate cancer (PCa). Methods: 65 low and 80 intermediate risk PCa patients were treated definitively with SBRT at Georgetown University Hospital between January 2008 and October 2011. All patients were treated to 35-37.5 Gy in 5 fractions delivered via the CyberKnife Radiosurgical System. Patients who received androgen deprivation therapy were excluded from this study. Pre- and post-treatment PSA and total testosterone levels were obtained during routine follow up visits. Biochemical relapse was defined as a PSA rise > 2 ng/mL above the nadir and analyzed using the Kaplan Meier method. The PSA nadir was defined as the lowest PSA value prior to biochemical relapse or as the lowest value recorded during follow up. Prostate ablation was defined as a PSA nadir < 0.2 ng/mL. Univariate logistic regression analysis was used to evaluate relevant variables on the likelihood of achieving a PSA nadir < 0.2 ng/mL. Results: The median age at the start of SBRT was 72 years. These patients had a median prostate volume of 36 cc with a median 25% of total cores involved. At a median follow up of 5.8 years, 84% and 37% of patients achieved a PSA nadir ≤ 0.5 ng/mL and < 0.2 ng/mL, respectively. Five low and 8 intermediate risk patients experienced a biochemical relapse; those who did not experience a biochemical relapse, achieved a median PSA nadir of 0.2 ng/mL. There was no difference between the 5-year bRFS rate for low (96.6%) and intermediate risk (97.4%) patients and the median time to PSA nadir was 36 months. Initial PSA (p = 0.024) and a lower testosterone at the time of the PSA nadir (p = 0.049) were found to be significant predictors of achieving a PSA nadir < 0.2 ng/mL. Conclusions: SBRT for low and intermediate risk PCa is a convenient treatment option with low PSA nadirs and a high rate of early bRFS. Less than 40% of patients achieved an ablative PSA nadir. Thus, the role of further dose escalation is an area of active investigation.

Intensity-Modulated Radiation Therapy with Stereotactic Body Radiation Therapy Boost for Unfavorable Prostate Cancer: A Report on 3-Year Toxicity

Background

Recent data suggest that intensity-modulated radiation therapy (IMRT) plus brachytherapy boost for unfavorable prostate cancer provides improved biochemical relapse-free survival over IMRT alone. Stereotactic body radiation therapy (SBRT) may be a less invasive alternative to brachytherapy boost. Here, we report the 3-year gastrointestinal (GI) and genitourinary (GU) toxicities of IMRT plus SBRT boost.

Materials and methods

Between March 2008 and September 2012, patients with prostate cancer were treated with robotic SBRT (19.5 Gy in three fractions) followed by fiducial-guided IMRT (45–50.4 Gy) on an institutional protocol. Toxicity was prospectively graded using the common terminology criteria for adverse events version 4.0 (CTCAEv.4) at the start of and at 1- to 6-month intervals after therapy. Rectal telangiectasias were graded using the Vienna Rectoscopy Score (VRS).

Results

At a median follow-up of 4.2 years (2.4–7.5), 108 patients (4 low-, 45 intermediate-, and 59 high-risk) with a median age of 74 years (55–92) were treated with SBRT plus IMRT, with 8% on anticoagulation and an additional 48% on antiplatelet therapy at the start of therapy. The cumulative incidence of late ≥grade 2 GI toxicity was 12%. Of these, 7% were due to late rectal bleeding, with six patients requiring up to two coagulation procedures. One patient with rectal telangiectasias was treated with hyperbaric oxygen (grade 3 toxicity). No rectal fistulas or stenoses were observed. Ten patients had multiple non-confluent telangiectasias (VRS grade 2), and three patients had multiple confluent telangiectasias (VRS grade 3). The cumulative incidence of late grade 3 GU toxicity was 6%. Most late toxicities were due to hematuria requiring bladder fulguration. There were no late ≥grade 4 GU toxicities.

Conclusion

Rates of clinically significant GI and GU toxicities are modest following IMRT plus SBRT boost. Future studies should compare cancer control, quality of life, and toxicity with other treatment modalities for patients with high-risk prostate cancer.

Predictors of multidomain decline in health-related quality of life after stereotactic body radiation therapy (SBRT) for prostate cancer

BACKGROUND

Stereotactic body radiation therapy (SBRT) for localized prostate cancer involves high-dose-per-fraction radiation treatments. Its use is increasing, but concerns remain about treatment-related toxicity. The authors assessed the incidence and predictors of a global decline in health-related quality of life (HRQOL) after prostate SBRT.

METHODS

From 2008 to 2014, 713 consecutive men with localized prostate cancer received treatment with SBRT according to a prospective institutional protocol. Expanded Prostate Cancer Index Composite (EPIC-26) HRQOL data were collected at baseline and longitudinally for 5 years. EPIC-26 is comprised of 5 domains. The primary endpoint was defined as a decline exceeding the clinically detectable threshold in ≥4 EPIC-26 domains, termed multidomain decline.

RESULTS

The median age was 69 years, 46% of patients had unfavorable intermediate-risk or high-risk disease, and 20% received androgen-deprivation therapy. During 1 to 3 months and 6 to 60 months after SBRT, 8% to 15% and 10% to 11% of patients had multidomain declines, respectively. On multivariable analysis, lower baseline bowel HRQOL (odds ratio, 1.8; 95% confidence interval, 1.2-2.7; P < .01) and baseline depression (odds ratio, 5.7; 95% confidence interval, 1.3-24.3; P = .02) independently predicted for multidomain decline. Only 3% to 4% of patients had long-term multidomain declines exceeding twice the clinical threshold, and 30% of such declines appeared to be related to prostate cancer treatment or progression of disease.

CONCLUSIONS

Prostate SBRT has minimal long-term impact on multidomain decline, and the majority of more significant multidomain declines appear to be unrelated to treatment. This emphasizes the importance of focusing not only on the side effects of prostate cancer treatment but also on other comorbid illnesses that contribute to overall HRQOL. Cancer 2017;123:1635-1642. © 2017 American Cancer Society.

MicroRNA-212 negatively regulates starvation induced autophagy in prostate cancer cells by inhibiting SIRT1 and is a modulator of angiogenesis and cellular senescence

Among a number of non-coding RNAs, role of microRNAs (miRNAs) in cancer cell proliferation, cancer initiation, development and metastasis have been extensively studied and miRNA based therapeutic approaches are being pursued. Prostate cancer (PCa) is a major health concern and several deregulated miRNAs have been described in PCa. miR-212 is differentially modulated in multiple cancers however its function remains elusive. In this study, we found that miR-212 is downregulated in PCa tissues when compared with benign adjacent regions (n = 40). Also, we observed reduced levels of circulatory miR-212 in serum from PCa patients (n = 40) when compared with healthy controls (n = 32). Elucidating the functional role of miR-212, we demonstrate that miR-212 negatively modulates starvation induced autophagy in PCa cells by targeting sirtuin 1 (SIRT1). Overexpression of miR-212 also leads to inhibition of angiogenesis and cellular senescence. In conclusion, our study indicates a functional role of miR-212 in PCa and suggests the development of miR-212 based therapies.

Proctitis 1 Week after Stereotactic Body Radiation Therapy for Prostate Cancer: Implications for Clinical Trial Design

Background

Proctitis following prostate cancer radiation therapy is a primary determinant of quality of life (QOL). While previous studies have assessed acute rectal morbidity at 1 month after stereotactic body radiotherapy (SBRT), little data exist on the prevalence and severity of rectal morbidity within the first week following treatment. This study reports the acute bowel morbidity 1 week following prostate SBRT.

Materials and methods

Between May 2013 and August 2014, 103 patients with clinically localized prostate cancer were treated with 35–36.25 Gy in five fractions using robotic SBRT delivered on a prospective clinical trial. Bowel toxicity was graded using the Common Terminology Criteria for Adverse Events version 4.0 (CTCAEv.4). Bowel QOL was assessed using the EPIC-26 questionnaire bowel domain at baseline, 1 week, 1 month, and 3 months. Time-dependent changes in bowel symptoms were statistically compared using the Wilcoxon signed-rank test. Clinically significant change was assessed by the minimally important difference (MID) in EPIC score. This was defined as a change of 1/2 standard deviation (SD) from the baseline score.

Results

One-hundred and three patients with a minimum of 3 months of follow-up were analyzed. The cumulative incidence of acute grade 2 gastrointestinal (GI) toxicity was 23%. There were no acute ≥ grade 3 bowel toxicities. EPIC bowel summary scores maximally declined at 1 week after SBRT (−13.9, p < 0.0001) before returning to baseline at 3 months after SBRT (+0.03, p = 0.94). Prior to treatment, 4.9% of men reported that their bowel bother was a moderate to big problem. This increased to 28.4% (p < 0.0001) 1 week after SBRT and returned to baseline at 3 months after SBRT (0.0%, p = 0.66). Only the bowel summary and bowel bother score declines at 1 week met the MID threshold for clinically significant change.

Conclusion

The rate and severity of acute proctitis following prostate SBRT peaked at 1 week after treatment and returned to baseline by 3 months. Toxicity assessment at 1 week can therefore minimize recall bias and should aid in the design of future clinical trials focused on accurately capturing and minimizing acute morbidity following SBRT.

Abstract 450: Serum biomarkers in patients treated with stereotactic body radiation therapy (SBRT) for prostate cancer

Purpose: The goal of this study was to determine the feasibility for developing prognostic protein biomarkers in serum samples from patients undergoing Stereotactic Body Radiation Therapy (SBRT) for organ confined prostate cancers.

Methods: 130 patients presenting with organ confined prostate cancers were treated with SBRT to doses of 35-36.25 Gy in 5 fractions. Peripheral blood samples were collected prospectively from patients at time 0 prior to radiation and serially after the first treatment (24 hours), follow-up months 1, 3, 6, 9, and 12 during the first year, and every 6 months thereafter, for up to 3 years. Processed study samples were analyzed by SomaLogic, Inc., using the SOMAscan Version 3 proteomic assay. Statistical analysis was performed on log-transformed data, with statistically significant differences identified by evaluating false discovery rate corrected p-values. Protein correlations were discovered with the Jonckheere-Terpstra (JT) test. Ingenuity Pathway Analysis (IPA) software was used to analyze cellular signaling pathways. PSA levels and clinical recurrence information were prospectively obtained at each follow-up visit and maintained in an institutional database.

Results:

Patient stratification by risk assessment identified 27 low-, 71 intermediate- and 32 high-risk patients in the study cohort. Proteins that function in cell proliferation, angiogenesis, protein signaling, gonad development, and cell migration correlated with Gleason's grade. CGA.LHB, KLK3, and CNTFR correlated both with tumor stage and Gleason's grade. With a median follow up of 3 years, ten patients experienced biochemical failures. While no proteins identified as differentially expressed in recurrent patients achieved significance, IPA pathway analysis of the top differentially expressed proteins converged on the IL-6 canonical pathway.

183 proteins were attributed to radiation effects on differential expression in patients by comparing pre-treatment to the 3 months post-treatment specimens. IPA network pathway analyses of these paired samples revealed changes in cell activation and signaling pathways, with the primary regulatory networks associated with ERK1/2, NF-κB, IFNG, ADIPOQ, histone 3, and histone 4. Of particular interest, high adiponectin levels in patients presenting with higher tumor stage decreased after radiation exposure, underscoring the potential for this molecule as a signal for determining response to radiation treatment.

Conclusion:

These hypothesis-generating experiments show differential serum protein levels in prostate cancer patient cohorts that have been stratified by risk factors and in longitudinal studies of patients following treatment with SBRT. Candidate biomarker proteins and molecular pathways have been identified for validation as potential predictors of prostate cancer response to radiation treatment.

Citation Format: Einsley Janowski, Simeng Suy, Rency S. Varghese, Olga Timofeeva, Stuart G. Field, Rachel Ostroff, Steve Williams, Anatoly Dritschilo, Sean P. Collins. Serum biomarkers in patients treated with stereotactic body radiation therapy (SBRT) for prostate cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 450.

Acute Urinary Morbidity Following Stereotactic Body Radiation Therapy for Prostate Cancer with Prophylactic Alpha-Adrenergic Antagonist and Urethral Dose Reduction

BACKGROUND

Stereotactic body radiation therapy (SBRT) delivers high doses of radiation to the prostate while minimizing radiation to the adjacent critical organs. Large fraction sizes may increase urinary morbidity due to unavoidable treatment of the prostatic urethra. This study reports rates of acute urinary morbidity following SBRT for localized prostate cancer with prophylactic alpha-adrenergic antagonist utilization and urethral dose reduction (UDR).

METHODS

From April 2013 to September 2014, 102 patients with clinically localized prostate cancer were treated with robotic SBRT to a total dose of 35-36.25 Gy in five fractions. UDR was employed to limit the maximum point dose of the prostatic urethra to 40 Gy. Prophylactic alpha-adrenergic antagonists were initiated 5 days prior to SBRT and continued until resolution of urinary symptoms. Quality of life (QoL) was assessed before and after treatment using the American Urological Association Symptom Score (AUA) and the Expanded Prostate Cancer Index Composite-26 (EPIC-26). Clinical significance was assessed using a minimally important difference (MID) of one half SD change from baseline.

RESULTS

One hundred two patients underwent definitive prostate SBRT with UDR and were followed for 3 months. No patient experienced acute urinary retention requiring catheterization. A mean baseline AUA symptom score of 9.06 significantly increased to 11.83 1-week post-SBRT (p = 0.0024) and 11.84 1-month post-SBRT (p = 0.0023) but returned to baseline by 3 months. A mean baseline EPIC-26 irritative/obstructive score of 87.7 decreased to 74.1 1-week post-SBRT (p < 0.0001) and 77.8 1-month post-SBRT (p < 0.0001) but returned to baseline at 3 months. EPIC-26 irritative/obstructive score changes were clinically significant, exceeding the MID of 6.0. At baseline, 8.9% of men described their urinary function as a moderate to big problem, and that proportion increased to 37.6% 1 week following completion of SBRT before returning to baseline by 3 months.

CONCLUSION

Stereotactic body radiation therapy for localized prostate cancer with utilization of prophylactic alpha-adrenergic antagonist and UDR was well tolerated as determined by acute urinary function and bother, and symptoms were comparable to those observed following conventionally fractionated external beam radiation therapy (EBRT). Longer follow-up is required to assess long-term toxicity and efficacy following SBRT with UDR.

Intensity-Modulated Radiation Therapy with Stereotactic Body Radiation Therapy Boost for Unfavorable Prostate Cancer: The Georgetown University Experience

Purpose/objective(s)

Stereotactic body radiation therapy (SBRT) is emerging as a minimally invasive alternative to brachytherapy to deliver highly conformal, dose-­escalated radiation therapy (RT) to the prostate. SBRT alone may not adequately cover the tumor extensions outside the prostate commonly seen in unfavorable prostate cancer. External beam radiation therapy (EBRT) with high dose rate brachytherapy boost is a proven effective therapy for unfavorable prostate cancer. This study reports on early prostate-specific antigen and prostate cancer-specific quality of life (QOL) outcomes in a cohort of unfavorable patients treated with intensity-modulated radiation therapy (IMRT) and SBRT boost.

Materials/methods

Prostate cancer patients treated with SBRT (19.5 Gy in three fractions) followed by fiducial-guided IMRT (45–50.4 Gy) from March 2008 to September 2012 were included in this retrospective review of prospectively collected data. Biochemical failure was assessed using the Phoenix definition. Patients completed the expanded prostate cancer index composite (EPIC)-26 at baseline, 1 month after the completion of RT, every 3 months for the first year, then every 6 months for a minimum of 2 years.

Results

One hundred eight patients (4 low-, 45 intermediate-, and 59 high-risk) with median age of 74 years completed treatment, with median follow-up of 4.4 years. Sixty-four percent of the patients received androgen deprivation therapy prior to the initiation of RT. The 3-year actuarial biochemical control rates were 100 and 89.8% for intermediate- and high-risk patients, respectively. At the initiation of RT, 9 and 5% of men felt their urinary and bowel function was a moderate to big problem, respectively. Mean EPIC urinary and bowel function and bother scores exhibited transient declines, with subsequent return to near baseline. At 2 years posttreatment, 13.7 and 5% of men felt their urinary and bowel function was a moderate to big problem, respectively.

Conclusion

At 3-year follow-up, biochemical control was favorable. Acute urinary and bowel symptoms were comparable to conventionally fractionated IMRT and brachytherapy. Patients recovered to near their baseline urinary and bowel function by 2 years posttreatment. A combination of IMRT with SBRT boost is well tolerated with minimal impact on prostate cancer-specific QOL.

Urethrogram-Directed Stereotactic Body Radiation Therapy for Clinically Localized Prostate Cancer in Patients with Contraindications to Magnetic Resonance Imaging

Purpose

Magnetic resonance imaging (MRI)-directed stereotactic body radiation therapy (SBRT) has been established as a safe and effective treatment for prostate cancer. For patients with contraindications to MRI, CT-urethrogram is an alternative imaging approach to identify the location of the prostatic apex to guide treatment. This study sought to evaluate the safety of urethrogram-directed SBRT for prostate cancer.

Methods

Between February 2009 and January 2014, 31 men with clinically localized prostate cancer were treated definitively with urethrogram-directed SBRT with or without supplemental intensity-modulated radiation therapy (IMRT) at Georgetown University Hospital. SBRT was delivered either as a primary treatment of 35–36.25 Gy in five fractions or as a boost of 19.5 Gy in three fractions followed by supplemental conventionally fractionated IMRT (45–50.4 Gy). Toxicities were recorded and scored using the Common Terminology Criteria for Adverse Events version 4.0 (CTCAE v.4.0).

Results

The median patient age was 70 years with a median prostate volume of 38 cc. The median follow-up was 3.7 years. The patients were elderly (Median age = 70), and comorbidities were common (Carlson comorbidity index ≥2 in 36%). Seventy-one percent of patients utilized alpha agonists prior to treatment, and 9.7% had prior procedures for benign prostatic hyperplasia. The 3-year actuarial incidence rates of ≥Grade 3 GU toxicity and ≥Grade 2 GI toxicity were 3.2 and 9.7%, respectively, and there were no Grade 4 or 5 toxicities.

Conclusion

Magnetic resonance imaging is the preferred imaging modality to guide prostate SBRT treatment. However, urethrogram-directed SBRT is a safe alternative for the treatment of patients with prostate cancer who are unable to undergo MRI.

Dysuria Following Stereotactic Body Radiation Therapy for Prostate Cancer

Background

Dysuria following prostate radiation therapy is a common toxicity that adversely affects patients’ quality of life and may be difficult to manage.

Methods

Two hundred four patients treated with stereotactic body radiation therapy (SBRT) from 2007 to 2010 for localized prostate carcinoma with a minimum follow-up of 3 years were included in this retrospective review of prospectively collected data. All patients were treated to 35–36.25 Gy in five fractions delivered with robotic SBRT with real time fiducial tracking. Dysuria and other lower urinary tract symptoms were assessed via Question 4b (Pain or burning on urination) of the expanded prostate index composite-26 and the American Urological Association (AUA) Symptom Score at baseline and at routine follow-up.

Results

Two hundred four patients (82 low-, 105 intermediate-, and 17 high-risk according to the D’Amico classification) at a median age of 69 years (range 48–91) received SBRT for their localized prostate cancer with a median follow-up of 47 months. Bother associated with dysuria significantly increased from a baseline of 12% to a maximum of 43% at 1 month (p < 0.0001). There were two distinct peaks of moderate to severe dysuria bother at 1 month and at 6–12 months, with 9% of patients experiencing a late transient dysuria flare. While a low level of dysuria was seen through the first 2 years of follow-up, it returned to below baseline by 2 years (p = 0.91). The median baseline AUA score of 7.5 significantly increased to 11 at 1 month (p < 0.0001) and returned to 7 at 3 months (p = 0.54). Patients with dysuria had a statistically higher AUA score at baseline and at all follow-ups up to 30 months. Dysuria significantly correlated with dose and AUA score on multivariate analysis. Frequency and strain significantly correlated with dysuria on stepwise multivariate analysis.

Conclusion

The rate and severity of dysuria following SBRT is comparable to patients treated with other radiation modalities.

Prostate specific antigen kinetics following robotic stereotactic body radiotherapy for localized prostate cancer

BACKGROUND

Stereotactic body radiotherapy (SBRT) has emerged as an effective treatment for localized prostate cancer. However, prostate specific antigen (PSA) kinetics after prostate SBRT have not been well characterized. The purpose of this study was to analyze the trend in PSA decline following robotic SBRT from a prospective cohort of patients.

MATERIAL AND METHODS

In total 175 patients were treated definitively for localized prostate cancer to a dose of 35-36.25 Gy in 5 fractions using robotic SBRT in the absence of androgen deprivation therapy (ADT). PSA and testosterone were collected at regular intervals following treatment and patients were assessed for biochemical failure and benign PSA bounce. A PSA nadir threshold of 0.5 ng/ml was used as a predictor of long-term disease-free survival. Multivariate logistic regression was used to assess the effect of disease specific covariates on the likelihood of achieving a PSA nadir less than threshold. PSA kinetics were analyzed a multi-component exponential model accounting for benign and malignant sources of PSA.

RESULTS AND CONCLUSION

At a median follow-up of 3 years, 70% of patients achieved a PSA nadir below 0.5 ng/ml with a median PSA nadir of 0.3 ng/ml at a median time to nadir of 30 months. In our cohort, 36.2% experienced a benign PSA bounce. Absence of PSA bounce, initial PSA, and testosterone at the time of nadir proved to be significant predictors of achieving a PSA nadir below threshold. PSA kinetics after prostate SBRT were well described with a functional volume model with fitted half-lives of 4.4 and 14.8 months for malignant and benign sources of PSA, respectively. Patients treated with prostate SBRT experience an initial period of rapid PSA decline followed by a slow decline which will likely result in lower PSA nadirs after longer follow-up. The long-term disease specific impacts of these results remain to be determined.

Late urinary toxicity modeling after stereotactic body radiotherapy (SBRT) in the definitive treatment of localized prostate cancer

BACKGROUND

Late urinary symptom flare has been shown to occur in a small subset of men treated with ultra- hypofractionated stereotactic body radiotherapy (SBRT) for prostate cancer. The purpose of this study was to use normal tissue complication probability modeling in an effort to derive SBRT specific dosimetric predictor's of late urinary flare.

MATERIAL AND METHODS

Two hundred and sixteen men were treated for localized prostate cancer using ultra- hypofractionated SBRT. A dose of 35-36.25 Gy in 5 fractions was delivered to the prostate and proximal seminal vesicles. Functional surveys were conducted before and after treatment to assess late toxicity. Phenomenologic NTCP models were fit to bladder DVHs and late urinary flare outcomes using maximum likelihood estimation.

RESULTS

Twenty-nine patients experienced late urinary flare within two years of completion of treatment. Fitting of bladder DVH data to a Lyman NTCP model resulted in parameter estimates of m, TD50, and n of 0.19 (0-0.47), 38.7 Gy (31.1-46.4), and 0.13 (-0.14-0.41), respectively. Subsequent fit to a hottest volume probit model revealed a significant association of late urinary flare with dose to the hottest 12.7% of bladder volume. Multivariate analysis resulted in a final model that included patient age and hottest volume probit model predictions. Kaplan-Meier analysis demonstrated a two-year urinary flare free survival of 95.7% in patients 65 years or older with a bladder D12.7% of 33.5 Gy or less, compared to 74.5% in patients meeting none of these criteria.

CONCLUSION

NTCP modeling of late urinary flare after ultra-hypofractionated prostate SBRT demonstrates a relatively small volume effect for dose to the bladder, suggesting that reduction of volume receiving elevated dose will result in decreased incidence of late urinary toxicity. Future studies will be needed to examine the impact of dose to other potential sources of late genitourinary toxicity.

Stereotactic Body Radiation Therapy for Prostate Cancer: What is the Appropriate Patient-Reported Outcome for Clinical Trial Design?

Purpose: Stereotactic body radiation therapy (SBRT) is increasingly utilized as primary treatment for clinically localized prostate cancer. Consensus regarding the appropriate patient-reported outcome (PRO) endpoints for clinical trials evaluating radiation modalities for early stage prostate cancer is lacking. To aid in clinical trial design, this study presents PROs over a 36-month period following SBRT for clinically localized prostate cancer.

Methods: Between February 2008 and September 2010, 174 hormone-naïve patients with clinically localized prostate cancer were treated with 35–36.25 Gy SBRT (CyberKnife, Accuray) delivered in 5 fractions. Patients completed the validated Expanded Prostate Cancer Index Composite (EPIC)-26 questionnaire at baseline and all follow-ups. The proportion of patients developing a clinically significant decline in each EPIC domain score was determined. The minimally important difference (MID) was defined as a change of one-half the standard deviation from the baseline. Per Radiation Therapy Oncology Group (RTOG) 0938, we also examined the patients who experienced a decline in EPIC urinary domain summary score of >2 points (unacceptable toxicity defined as ≥60% of all patients reporting this degree of decline) and EPIC bowel domain summary score of >5 points (unacceptable toxicity defined as >55% of all patients reporting this degree of decline) from baseline to 1 year.

Results: A total of 174 patients at a median age of 69 years received SBRT with a minimum follow-up of 36 months. The proportion of patients reporting a clinically significant decline (MID for urinary/bowel are 5.5/4.4) in EPIC urinary/bowel domain scores was 34%/30% at 6 months, 40%/32.2% at 12 months, and 32.8%/21.5% at 36 months. The patients reporting a decrease in the EPIC urinary domain summary score of >2 points was 43.2% (CI: 33.7%, 54.6%) at 6 months, 51.6% (CI: 43.4%, 59.7%) at 12 months, and 41.8% (CI: 33.3%, 50.6%) at 36 months. The patients reporting a decrease in the EPIC bowel domain summary score of >5 points was 29.6% (CI: 21.9%, 39.3%) at 6 months, 29% (CI: 22%, 36.8%) at 12 months, and 22.4% (CI: 15.7%, 30.4%) at 36 months.

Conclusion: Following prostate SBRT, clinically significant urinary symptoms are more common than bowel symptoms. Our prostate SBRT treatment protocol meets the RTOG 0938 criteria for moving forward to a Phase III trial comparing it to conventionally fractionated radiation therapy. Notably, between 12 and 36 months, the proportion of patients reporting a significant decrease in both EPIC urinary and bowel domain scores declined, suggesting a late improvement in these symptom domains. Further investigation is needed to elucidate (1) which EPIC domains bear the greatest influence on post-treatment quality of life and (2) at what time point PRO endpoint(s) should be assessed.

Hematuria following stereotactic body radiation therapy (SBRT) for clinically localized prostate cancer

BACKGROUND

Hematuria following prostate radiotherapy is a known toxicity that may adversely affect a patient's quality of life. Given the higher dose of radiation per fraction using stereotactic body radiation therapy (SBRT) there is concern that post-SBRT hematuria would be more common than with alternative radiation therapy approaches. Herein, we describe the incidence and severity of hematuria following stereotactic body radiation therapy (SBRT) for prostate cancer at our institution.

METHODS

Two hundred and eight consecutive patients with prostate cancer treated with SBRT monotherapy with at least three years of follow-up were included in this retrospective analysis. Treatment was delivered using the CyberKnife® (Accuray) to doses of 35-36.25 Gy in 5 fractions. Toxicities were scored using the CTCAE v.4. Hematuria was counted at the highest grade it occurred in the acute and late setting for each patient. Cystoscopy findings were retrospectively reviewed. Univariate and multivariate analyses were performed. Hematuria-associated bother was assessed via the Expanded Prostate Index Composite (EPIC)-26.

RESULTS

The median age was 69 years with a median prostate volume of 39 cc. With a median follow-up of 48 months, 38 patients (18.3%) experienced at least one episode of hematuria. Median time to hematuria was 13.5 months. In the late period, there were three grade 3 events and five grade 2 events. There were no grade 4 or 5 events. The 3-year actuarial incidence of late hematuria ≥ grade 2 was 2.4%. On univariate analysis, prostate volume (p = 0.022) and history of prior procedure(s) for benign prostatic hypertrophy (BPH) (p = 0.002) were significantly associated with hematuria. On multivariate analysis, history of prior procedure(s) for BPH (p < 0.0001) and α1A antagonist use (p = 0.008) were significantly associated with the development of hematuria.

CONCLUSIONS

SBRT for prostate cancer was well tolerated with hematuria rates comparable to other radiation modalities. Patients factors associated with BPH, such as larger prostate volume, alpha antagonist usage, and prior history of procedures for BPH are at increased risk for the development of hematuria.

Detection of circulatory microRNAs in prostate cancer

Prostate cancer (PCa) is one of the most common cancer worldwide and accounts for 14.4 % of all new cancer cases. The clinical outcome and management of PCa can be significantly improved by use of biomarker assays for early detection, prognosis and also for prediction and monitoring of treatment response. MiRNAs are short, endogenous, single-stranded RNA molecules that play important role in regulation of gene expression and can modulate a number of cellular processes. Discovery of miRNAs in circulation has not only facilitated understanding their role in various diseases but also paved new avenues for biomarker discovery due to their ease of access and stability. The fact that a minimally invasive test based on miRNAs profiles can distinguish the presence or absence of disease illustrates immense potential of these molecules as predictive biomarkers.In this chapter, we have summarized the presumed mechanisms of miRNA release into the circulation and systematically summarized the studies of circulatory miRNAs in PCa. Also, we have mainly focused on the methodology of identification of circulatory miRNAs from biofluids.

Proctitis following stereotactic body radiation therapy for prostate cancer

Background

Proctitis after radiation therapy for prostate cancer remains an ongoing clinical challenge and critical quality of life issue. SBRT could minimize rectal toxicity by reducing the volume of rectum receiving high radiation doses and offers the potential radiobiologic benefits of hypofractionation. This study sought to evaluate the incidence and severity of proctitis following SBRT for prostate cancer.

Methods

Between February 2008 and July 2011, 269 men with clinically localized prostate cancer were treated definitively with SBRT monotherapy at Georgetown University Hospital. All patients were treated to 35-36.25Gy in 5 fractions delivered with the CyberKnife Radiosurgical System (Accuray). Rectal bleeding was recorded and scored using the CTCAE v.4. Telangiectasias were graded using the Vienna Rectoscopy Score (VRS). Proctitis was assessed via the Bowel domain of the Expanded Prostate Index Composite (EPIC)-26 at baseline and at 1, 3, 6, 9, 12, 18 and 24 months post-SBRT.

Results

The median age was 69 years with a median prostate volume of 39 cc. The median follow-up was 3.9 years with a minimum follow-up of two years. The 2-year actuarial incidence of late rectal bleeding ≥ grade 2 was 1.5%. Endoscopy revealed VRS Grade 2 rectal telangiectasias in 11% of patients. All proctitis symptoms increased at one month post-SBRT but returned to near-baseline with longer follow-up. The most bothersome symptoms were bowel urgency and frequency. At one month post-SBRT, 11.2% and 8.5% of patients reported a moderate to big problem with bowel urgency and frequency, respectively. The EPIC bowel summary scores declined transiently at 1 month and experienced a second, more protracted decline between 6 months and 18 months before returning to near-baseline at two years post-SBRT. Prior to treatment, 4.1% of men felt their bowel function was a moderate to big problem which increased to 11.5% one month post-SBRT but returned to near-baseline at two years post-SBRT.

Conclusions

In this single institution cohort, the rate and severity of proctitis observed following SBRT is low. QOL decreased on follow-up; however, our results compare favorably to those reported for patients treated with alternative radiation modalities. Future prospective randomized studies are needed to confirm these observations.

Stereotactic body radiation therapy (SBRT) for prostate cancer in men with large prostates (≥50 cm(3))

BACKGROUND

Patients with large prostate volumes have been shown to have higher rates of genitourinary and gastrointestinal toxicities after conventional radiation therapy for prostate cancer. The efficacy and toxicity of stereotactic body radiation therapy (SBRT), which delivers fewer high-dose fractions of radiation treatment, is unknown for large prostate volume prostate cancer patients. We report our early experience using SBRT for localized prostate cancer in patients with large prostate volumes.

METHODS

57 patients with prostate volumes ≥50 cm(3) prior to treatment with SBRT for localized prostate carcinoma and with a minimum follow up of two years were included in this retrospective review of prospectively collected data. Treatment was delivered using Cyberknife (Accuray) with doses of 35-36.25 Gy in 5 fractions. Biochemical control was assessed using the Phoenix definition. Toxicities were scored using the CTCAE v.4. Quality of life was assessed using the American Urological Association (AUA) Symptom Score and the Expanded Prostate Cancer Index Composite (EPIC)-26.

RESULTS

57 patients (23 low-, 25 intermediate- and 9 high-risk according to the D'Amico classification) at a median age of 69 years (range, 54-83 years) received SBRT with a median follow-up of 2.9 years. The median prostate size was 62.9 cm(3) (range 50-138.7 cm(3)). 33.3% of patients received ADT. The median pre-treatment prostate-specific antigen (PSA) was 6.5 ng/ml and decreased to a median PSA of 0.4 ng/ml by 2 years (p <0.0001). A mean baseline AUA symptom score of 7.5 significantly increased to 13 at 1 month (p = 0.001) and returned to baseline by 3 months (p = 0.21). 23% of patients experienced a late transient urinary symptom flare in the first two years following treatment. Mean baseline EPIC bowel scores of 95.8 decreased to 78.1 at 1 month (p <0.0001), but subsequently improved to 93.5 three months (p = 0.08). The 2-year actuarial incidence rates of GU and GI toxicity ≥ grade 2 were 49.1% and 1.8%, respectively. Two patients (3.5%) experienced grade 3 urinary toxicity, and no patient experienced grade 3 gastrointestinal toxicity.

CONCLUSIONS

SBRT for clinically localized prostate cancer was well tolerated in men with large prostate volumes.

Improved irritative voiding symptoms 3 years after stereotactic body radiation therapy for prostate cancer

Background: Irritative voiding symptoms are common in elderly men and following prostate radiotherapy. There is limited clinical data on the impact of hypofractionated treatment on irritative voiding symptoms. This study sought to evaluate urgency, frequency, and nocturia following stereotactic body radiation therapy (SBRT) for prostate cancer.

Methods: Patients treated with SBRT monotherapy for localized prostate cancer from August 2007 to July 2011 at Georgetown University Hospital were included in this study. Treatment was delivered using the CyberKnife^® with doses of 35–36.25 Gy in five fractions. Patient-reported urinary symptoms were assessed using the International Prostate Symptom Score (IPSS) before treatment and at 1, 3, 6, 9, and 12 months post-treatment and every 6 months thereafter.

Results: Two hundred four patients at a median age of 69 years received SBRT with a median follow-up of 4.8 years. Prior to treatment, 50.0% of patients reported moderate to severe lower urinary tract symptoms (LUTS) and 17.7% felt that urinary frequency was a moderate to big problem. The mean prostate volume was 39 cc and 8% had prior procedures for benign prostatic hyperplasia. A mean baseline IPSS-irritative (IPSS-I) score of 4.8 significantly increased to 6.5 at 1 month (p < 0.0001), however returned to baseline at 3 months (p = 0.73). The IPSS-I score returned to baseline in 91% of patients by 6 months and 96% of patients by 2 years. Transient increases in irritative voiding symptoms were common at 1 year. The mean baseline IPSS-I score decreased to 4.4 at 24 months (p = 0.03) and 3.7 at 36 months (p < 0.0001). In men with moderate to severe LUTS (IPSS ≥ 8) at baseline, the mean IPSS-I decreased from a baseline score of 6.8–4.9 at 3 years post-SBRT. This decrease was both statistically (p < 0.0001) and clinically significant (minimally important difference = 1.45). Only 14.6% of patients felt that urinary frequency was a moderate to big problem at 3 years post-SBRT (p = 0.23).

Conclusion: Treatment of prostate cancer with SBRT resulted in an acute increase in irritative urinary symptoms that peaked within the first month post-treatment. Irritative voiding symptoms returned to baseline in the majority of patients by 3 months post-SBRT and were actually improved from baseline at 3 years post-SBRT.