Prognostic value of DNA ploidy and automated assessment of stroma fraction in prostate cancer.

The combination of DNA ploidy and automatically estimated stroma fraction has been shown to correlate with recurrence and cancer death in colorectal cancer. We aimed to extend this observation and evaluate the prognostic importance of this combined marker in prostate cancer. DNA ploidy status was determined by image cytometry and the stroma fraction was estimated automatically on hematoxylin and eosin stained sections in three tumor samples from each patient to account for tumor heterogeneity. The optimal threshold for low (≤56%) and high (>56%) stroma fraction was identified in a discovery cohort (n = 253). The combined marker was validated in an independent patient cohort (n = 259) with biochemical recurrence as endpoint. The combined marker predicted biochemical recurrence independently in the validation cohort. Multivariable analysis showed that the highest risk of recurrence was observed for patients with samples that had both non‐diploid ploidy status and a high stroma fraction (hazard ratio: 2.51, 95% confidence interval: 1.18–5.34). In conclusion, we suggest the combination of DNA ploidy and automatically estimated stroma fraction as a prognostic marker for the risk stratification of prostate cancer patients. It may also be a potential generic marker as concurrent results have been described in colorectal cancer. What's new? The stroma that surrounds tumor cells can have significant effects on tumor growth and behavior. Another hallmark of cancer is aneuploidy caused by genomic instability, which offers an important prognostic marker in several cancer types. In this study, the authors found that combining these two markers—stromal fraction and DNA ploidy—provided a significant predictor of biochemical recurrence in prostate cancer. The low cost, high throughput, and accuracy of digital analysis using this combined method thus promise to provide improved prognostic biomarkers in prostate cancer. [ABSTRACT FROM AUTHOR]