A paper published a few weeks ago in Prostate Cancer and Prostatic Diseases has suggested that there may be a meaningful association between the presence of systemic inflammation and survival among men with prostate cancer.
As Shafique et al. carefully point out, there has been other evidence of a relationship between systemic inflammation and survival, but the evidence to date is limited — and the current study, while helpful, does not absolutely confirm the clinical value of assessing patients for the presence of systemic inflammation. (Note that the full text of this article is available on the Mescape web site.)
First, we should probably explain what is meant by “systemic inflammation” and how it can be measured (based on a simple blood sample).
Chronic systemic inflammation is one result of release of normal biological activators known as ”pro-inflammatory cytokines” from immune-related cells in the body and the consequent, chronic activation of the immune system. In other words, just as your immune system is activated in response to certain types of infection, it may also be activated in response to prostate cancer. The activity of the immune system can be measured by taking blood samples from patients and assaying these blood samples for levels of things like C-reactive protein and albumin, and the ratio of neutrophils to lymphocytes (the so-called NLR). In this particular study, the authors used the NLR and something called the modified Glasgow prognostic score (mGPS). The mGPS is a score that is based on levels of albumion and C-reactive protein in individual patients.
In considering the value of this study data, we should be very clear that PSA testing was not customary in Scotland until very recently, and so most of the participants in this study would have been diagnosed with advanced forms of prostate cancer. This means that we have no real idea whether assessment of systemic inflammation among men with early stage disease would be valuable or not based on this study.
So, what did this study actually show?
Data from blood samples from a cohort of 897 patients diagnosed with prostate cancer among the more than 220,000 patients who participated in the Glasgow Inflammation Outcome Study (GIOS) between 2000 and 2007) were used. These 897 men were all diagnosed with prostate cancer up to 2 years before or 2 years after blood samples were taken for the GIOS. From these data, the authors report that:
- 575/897 patients (64 percent) were aged 75 years or older.
- The average (median) follow-up time from diagnosis of prostate cancer was 2.6 years.
- 422/897 of the patients (47 percent) died over a maximum follow-up period of 6.2 years from diagnosis with prostate cancer.
- Patients with an elevated mGPS were more likely to
- Be > 75 years of age
- Have a Gleason score of ≥ 8
- The presence of systemic inflammation appeared to have significant prognostic value.
- Regardless of age, socioeconomic status, Gleason score, and NLR, an elevated mGPS predicted
- Poorer overall 5-year survival
- Poorer relative 5-year survival
- An elevated mGPS was significantly associated with an increased risk of death among men with aggressive, clinically significant prostate cancer (Gleason scores of 8-10).
The authors conclude that:
- The mGPS is a strong measure of systemic inflammation
- Prostate cancer patients with an elevated mGPS had
- A higher rate of overall mortality (than those with a normal mGPS level).
- Higher-grade disease (than those with a normal mGPS level).
- Inflammation-based prognostic scores can potentially predict outcomes in patients with prostate cancer.
Now evaluating men’s mGPS levels is relatively easy and cheap. As previously stated, it requires only a blood sample. The question is whether knowing a patient’s mGPS level (if you already know his PSA and his Gleason score) will (or should) actually change the type of management/treatment that is provided.
The authors have basically put forward the hypothesis that adding mGPS data to other available data (PSA, Gleason score, etc.) may allow us to better identify men at high risk for clinically significant prostate cancer. The “New” Prostate Cancer InfoLink thinks that this needs to be tested prospectively in a clinical trial or trials (which would really not be that difficult to do). We may be able to use such data to better define risk for clinically significant prostate cancer relatively simply through the use of such a test — especially in those men with intermediate-risk prostate cancer and Gleason scores of less than 8.