Baseline prostate inflammation is associated with a reduced risk of prostate cancer in men undergoing repeat prostate biopsy: results from the REDUCE study

Is histological prostate inflammation in an initial prostate biopsy a predictor of prostate cancer on repeat biopsy?

PURPOSE

To investigate whether histological inflammation detected in an initial prostate biopsy can predict the risk of prostate cancer on a repeat biopsy.

METHODS

This was a retrospective study of 171 patients who underwent repeat prostate biopsy for persistently elevated prostate-specific antigen after an initial negative biopsy result. The enrolled patients were divided into two groups according to the results of the repeat biopsy: the noncancer group (n = 126) and the cancer group (n = 45). Multivariate regression analysis was used to determine the effect of inflammation grade, aggressiveness, and prostate-related parameters on the detection of prostate cancer at the repeat biopsy.

RESULTS

Prostate inflammation grade (p = 0.005) and aggressiveness (p = 0.001) in the initial biopsy were significantly different between the cancer and noncancer groups. Factors associated with the risk of prostate cancer at the repeat biopsy were age [odds ratio (OR) 1.08; 95 % confidence interval (CI) 1.03-1.14], prostate-specific antigen density (OR 24.30; 95 % CI 9.3-62.9), prostate-specific antigen velocity (OR 1.05; 95 % CI 1.01-1.09), and inflammation aggressiveness (OR 0.05; 95 % CI 0.01-0.27).

CONCLUSIONS

A histological inflammatory finding at the initial prostate biopsy was negatively associated with prostate cancer detection in repeat biopsy. This result could be useful to determine the need for repeat prostate biopsy in patients with persistently elevated prostate-specific antigen.

Smoking Is Associated with Acute and Chronic Prostatic Inflammation: Results from the REDUCE Study

Both anti- and proinflammatory effects of cigarette smoking have been described. As prostate inflammation is common, we hypothesized smoking could contribute to prostate inflammation. Thus, we evaluated the association of smoking status with acute and chronic inflammation within the prostate of men undergoing prostate biopsy. We retrospectively analyzed 8,190 men ages 50 to 75 years with PSA levels between 2.5 and 10 ng/mL enrolled in the Reduction by Dutasteride of Prostate Cancer Events study. Smoking status was self-defined as never, former, or current. Prostate inflammation was assessed by systematic central review blinded to smoking status. The association of smoking with inflammation in the baseline, 2-year, and 4-year biopsies was evaluated with univariable and multivariable logistic regressions. At study enrollment, 1,233 (15%), 3,203 (39%), and 3,754 (46%) men were current, former, and never smokers, respectively. Current smokers were significantly younger and had smaller prostates than former and never smokers (all P < 0.05). Former smokers were significantly heavier than current and never smokers (P < 0.001). Acute and chronic prostate inflammations were identified in 1,261 (15%) and 6,352 (78%) baseline biopsies, respectively. In univariable analysis, current smokers were more likely to have acute inflammation than former (OR, 1.35; P, 0.001) and never smokers (OR, 1.36; P, 0.001). The results were unchanged at 2- and 4-year biopsies. In contrast, current smoking was linked with chronic inflammation in the baseline biopsy, but not at 2- and 4-year biopsies. In conclusion, among men undergoing prostate biopsy, current smoking was independently associated with acute and possibly chronic prostate inflammations.

Chronic inflammatory mediators enhance prostate cancer development and progression

Chronic inflammation is postulated to influence prostate cancer progression. Preclinical studies have claimed that inflammatory mediators are involved in prostate cancer development and therefore suggested these as attractive targets for intervention. However, among the many pro-inflammatory mediators, there is no consensus regarding the identity of the primary one(s). In clinical studies, chronic inflammation has been found in prostate tumor specimens, and tissues resected for treatment of benign prostatic hyperplasia (BPH). Although collective evidence from molecular, experimental and clinical data suggests that inflammation can contribute or promote prostate carcinogenesis, an etiologic link has not yet been established. Moreover, the role of chronic inflammation in the onset of castration resistant and metastatic disease is unclear. Therefore it is important to open a dialog regarding recent findings on how chronic inflammatory mediators contribute to prostate cancer progression, and their usefulness to prevent disease progression. In this commentary, we assess the current literature with respect to chronic inflammation as a potential initiator and promoter of prostate carcinogenesis and discuss the prospects for its potential clinical applications.

Impact of prostate inflammation on lesion development in the POET3(+)Pten(+/-) mouse model of prostate carcinogenesis

Evidence linking prostatitis and prostate cancer development is contradictory. To study this link, the POET3 mouse, an inducible model of prostatitis, was crossed with a Pten-loss model of prostate cancer (Pten(+/-)) containing the ROSA26 luciferase allele to monitor prostate size. Prostatitis was induced, and prostate bioluminescence was tracked over 12 months, with lesion development, inflammation, and cytokine expression analyzed at 4, 8, and 12 months and compared with mice without induction of prostatitis. Acute prostatitis led to more proliferative epithelium and enhanced bioluminescence. However, 4 months after initiation of prostatitis, mice with induced inflammation had lower grade pre-neoplastic lesions. A trend existed toward greater development of carcinoma 12 months after induction of inflammation, including one of two mice with carcinoma developing perineural invasion. Two of 18 mice at the later time points developed lesions with similarities to proliferative inflammatory atrophy, including one mouse with associated carcinoma. Pten(+/-) mice developed spontaneous inflammation, and prostatitis was similar among groups of mice at 8 and 12 months. Analyzed as one cohort, lesion number and grade were positively correlated with prostatitis. Specifically, amounts of CD11b(+)Gr1(+) cells were correlated with lesion development. These results support the hypothesis that myeloid-based inflammation is associated with lesion development in the murine prostate, and previous bouts of CD8-driven prostatitis may promote invasion in the Pten(+/-) model of cancer.

Chronic inflammation in benign prostate tissue is associated with high-grade prostate cancer in the placebo arm of the prostate cancer prevention trial

BACKGROUND

Chronic inflammation is hypothesized to influence prostate cancer development, although a definitive link has not been established.

METHODS

Prostate cancer cases (N = 191) detected on a for-cause (clinically indicated) or end-of-study (protocol directed) biopsy, and frequency-matched controls (N = 209), defined as negative for cancer on an end-of-study biopsy, were sampled from the placebo arm of the Prostate Cancer Prevention Trial. Inflammation prevalence and extent in benign areas of biopsy cores were visually assessed using digital images of hematoxylin and eosin-stained sections. Logistic regression was used to estimate associations.

RESULTS

Of note, 86.2% of cases and 78.2% of controls had at least one biopsy core (of three assessed) with inflammation in benign areas, most of which was chronic. Men who had at least one biopsy core with inflammation had 1.78 [95% confidence interval (CI), 1.04-3.06] times the odds of prostate cancer compared with men who had zero cores with inflammation. The association was stronger for high-grade disease (Gleason sum 7-10, N = 94; OR, 2.24; 95% CI, 1.06-4.71). These patterns were present when restricting to cases and controls in whom intraprostatic inflammation was the least likely to have influenced biopsy recommendation because their prostate-specific antigen (PSA) was low (<2 ng/mL at biopsy).

CONCLUSION

Inflammation, most of which was chronic, was common in benign prostate tissue, and was positively associated with prostate cancer, especially high grade. The association did not seem to be due to detection bias.

IMPACT

This study supports an etiologic link between inflammation and prostate carcinogenesis, and suggests an avenue for prevention by mitigating intraprostatic inflammation.