Elevated C-Reactive Protein Tied to Lower Survival Rates in Prostate Cancer

A new meta-analysis supports the idea that C-reactive protein (CRP) levels could be a meaningful prognostic biomarker in people with prostate cancer.

The report offers new data in what has heretofore been a controversial issue in the scientific literature surrounding prostate cancer. The report was published in Frontiers in Endocrinology.

One of the reasons for the high rates of survival among people with prostate cancer is that most cases are discovered while the cancer is still localized, noted the study authors. Yet, about 3 in 10 patients will have a recurrence of cancer, and outcomes for those cases may be improved by the ability to accurately identify the patients at the highest risk of poor outcomes.

Currently, factors such as Gleason score and alkaline and albumin levels are used as survival indicators, and the authors said systemic inflammation might also be tied to survival. Yet, they said CRP has remained controversial as a predictive biomarker for survival in prostate cancer, despite its being found to correlate with survival in other urological cancers.

“Some studies suggested that prostate cancer patients with elevated CRP levels often had worse survival,” the authors said. “Some other studies had different views and believed that there was no significant correlation between the CRP level and the prognosis of prostate cancer patients.”

Those studies used small sample sizes, which made it difficult to draw firm conclusions. The investigators therefore set out to perform a meta-analysis in hopes of using a larger data set to help settle the question. They included 16 studies in their final analysis, representing 13,555 people with prostate cancer.

Their meta-analysis showed that elevated CRP levels were linked with survival across categories. The HR for overall survival was 1.752 for patients with elevated CRP (95% CI, 1.304-2.355; P = .000). Similar correlations were found between CRP and cancer-specific survival and progression-free survival, the authors said.

In the initial analysis, the investigators found significant heterogeneity between studies, and so they performed a subgroup analysis based on disease stage. That analysis resulted in less heterogeneity, but it did not change the result that elevated CRP appeared to increase the risk of mortality. Furthermore, they said the results were the same both in metastatic and localized cases of prostate cancer.

They cited a number of possible reasons for the apparent connection between CRP and survival. It could be that chronic inflammation, which is linked with CRP, promotes the growth of vascular endothelial cells, which in turn provides a beneficial environment for tumors. But the authors said it could also be that the inflammatory reaction is a response to rapid tumor growth.

In either case, however, the authors said their data support the idea that CRP is an important biomarker in these patients. They added that more studies would be helpful to better understand the issue, and they noted that the studies included in their meta-analysis used different techniques to detect CRP, which could affect the outcomes.

Reference

Zhou K, Li C, Chen T, Zhang X, Ma B. C-reactive protein levels could be a prognosis predictor of prostate cancer: a meta-analysis. Front Endocrinol (Lausanne). Published online February 3, 2023. doi:10.3389/fendo.2023.1111277