[Localized intermediate- to high-risk prostate cancer]

Radiotherapy-Related Gene Signature in Prostate Cancer

Simple Summary

Radiation therapy (RT) is an established therapeutic regimen for prostate cancer patients which aims for the direct elimination of tumor cells in the prostate gland and occasionally at distant anatomic sites. In this study, we performed next-generation sequencing-based gene expression analysis in peripheral blood from prostate cancer patients obtained pre- and post-radiotherapy and found six independently down-regulated genes including CCR7, FCGR2B, BTLA, CD6, CD3D, and CD3E. The analysis of the expression of the 6-genes as a signature also revealed significantly lower levels post- vs. pre-radiotherapy. Data extracted from the PRAD (PRostate ADenocarcinomas) dataset linked low levels of the 6-gene signature to better survival. More importantly, this 6-gene signature strongly correlated with a favorable prognosis regardless of poor standard clinicopathological parameters (i.e., Gleason score ≥ 8 and T3), thus highlighting its potential predictive value.

Abstract

Radiotherapy for localized prostate cancer has increased the cure and survival rates of patients. Besides its local tumoricidal effects, ionizing radiation has been linked to mechanisms leading to systemic immune activation, a phenomenon called the abscopal effect. In this study, we performed gene expression analysis on peripheral blood from prostate cancer patients obtained post- radiotherapy and showed that 6 genes, including CCR7, FCGR2B, BTLA, CD6, CD3D, and CD3E, were down-regulated by a range of 1.5–2.5-fold as compared to pre-radiotherapy samples. The expression of the signature consisting of these six genes was also significantly lower post- vs. pre-radiotherapy. These genes are involved in various tumor-promoting immune pathways and their down-regulation post-radiotherapy could be considered beneficial for patients. This is supported by the fact that low mRNA expression levels for the 6-gene signature in the prostate tumor tissue was linked to better survival. Importantly, we report that this 6-gene signature strongly correlated with a favorable prognosis regardless of poor standard clinicopathological parameters (i.e., Gleason score ≥ 8 and T3 (including T3a and T3b). Our pioneering data open the possibility that the 6-gene signature identified herein may have a predictive value, but this requires further long-term studies.

[On the practice of therapy decision in locally limited prostate cancer: surgery vs. radiation-who benefits? : Allocation and results of a monocentric, cumulative long-term study]

AIM

The goal of this two-armed observational study was to map the clinical therapy effectiveness of radical prostatovesiculectomy (RPVE) and external beam radiation therapy (EBRT) in locally limited prostate cancer (PCA) in direct comparison over 20 years under clinical conditions. Retrospectively, the various variables and predictors for the individual therapy decision were identified, and the preference was to compared with studies on survival and recurrence characteristics. The presentation of toxicity was not the focus of this work.

METHODOLOGY

In all, 743 patients from a single center were enrolled according to biopsy/staging chronologically in the sequence of the initial consultation after clarification and informed consent: 494 patients were in the RPVE arm and 249 patients in the EBRT arm. We used retrospective data analysis with univariate and multivariate comparisons in the alternative therapy arms. Multivariate logical regression models were developed to objectify the allocation process. Univariate processing of survival analyses, the comparison of tumor- and comorbidity-specific mortality rates was co-founded.

RESULTS

Predictive variables for RPVE vs. EBRT therapy decision are significantly age, Gleason score, D'Amico index, Charlson index, prostate-specific antigen (PSA), and prostate volume. There was no significance level for the biopsy score. The age gap was in the median 67 (RPVE) and 73 (EBRT) years. Overall survival (n = 734, 20 years, all risks) in the RPVE arm was 56.8% (95% confidence interval [CI] 45.1-67.0%) and in the EBRT arm 19.2% (95%CI 9.2-31.8%). Comorbid risk was highly significantly (p < 0.0001) different (27.1% [95%CI 18.0-36.1%] in the RPVE arm, and 60.4% [95%CI 47.3-73.5%] in the EBRT arm). The risk of tumor-specific death at 16.2% (95%CI 8.1-24.4%) after RPVE and 20.5% (95%CI 11.7-29.3%) after EBRT was not significantly different (p = 0.2122, overlapping 95%CI). After stratification, a clear advantage can be demonstrated for the high-risk tumors after allocation to the RPVE arm.

CONCLUSIONS

The complexity of the predictive variables of the PCA further complicates the individual therapy decision. According to our data, the higher D'Amico score, the rather low Charlson index, a high Gleason score and a higher organ volume speak for a valid therapy for RPVE.