CRP Elevation in Common Malignancies
Yes, CRP is frequently elevated in common malignancies, with solid tumors showing median CRP levels of approximately 46 mg/L, though considerable variability exists both within and across different cancer types. 1, 2, 3
Magnitude of CRP Elevation in Malignancy
Solid tumors demonstrate median CRP levels of 46 mg/L, which is substantially lower than bacterial infections (120 mg/L) but higher than cardiovascular disease (6 mg/L). 1, 2, 3
Approximately 33% of hospitalized cancer patients have CRP values less than 10 mg/L, indicating that normal or mildly elevated CRP does not exclude malignancy. 1
The degree of CRP elevation often parallels tumor progression and pathological stage, with preoperative CRP levels correlating with disease advancement in gastric cancer and other malignancies. 4
Prognostic Significance
Elevated preoperative CRP is a determinant predictor of lower survival rates in multiple cancer types including esophageal, colorectal, hepatocellular, pancreatic, bladder, renal, ovarian, and cervical cancers after surgical resection. 4
The modified Glasgow Prognostic Score (mGPS), which grades inflammatory response using CRP and albumin, is highly predictive of morbidity and mortality in cancer patients. 1
In patients with invasive breast cancer, CRP levels >3 mg/L at diagnosis confer a 1.7-fold increased risk of death compared to those with CRP <1 mg/L. 5
Individuals from the general population with CRP in the highest versus lowest quintile have a 1.3-fold increased risk of developing cancer of any type and a 2-fold increased risk of lung cancer. 5
Mechanistic Basis
CRP is produced by hepatocytes in response to inflammatory cytokines, particularly IL-6 and TNF-alpha, from the tumor microenvironment. 1, 4
Studies have identified associations between single-nucleotide polymorphisms in inflammatory genes (IL6, IL13, TNF-alpha, IL4, IL1B) and higher symptom burden in cancer patients. 1
The elevation reflects the chronic inflammatory state associated with malignancy, linking inflammation and cancer pathogenesis. 4, 6
Diagnostic Limitations
CRP has limited diagnostic accuracy for detecting secondary pleural malignancy, with sensitivity of 0.71 and specificity of only 0.56 at a cut-point of 35.5 mg/L. 1
The British Thoracic Society guideline states there is insufficient evidence to support using serum CRP to diagnose secondary pleural malignancy. 1
CRP is neither organ-specific nor tumor-specific, limiting its utility as a screening or diagnostic tool for malignancy. 7
Clinical Implications
In lung cancer patients receiving chemotherapy, a CRP cutoff value of ≥6.74 mg/dL can distinguish infection from malignancy-related elevation with 91.3% sensitivity and 86.6% specificity. 8
CRP measurement is simple, cheap, and available in daily practice, serving as an additional prognostic predictor for survival and post-treatment monitoring. 4
Baseline CRP might be a prognostic factor in oncological diseases, with normal levels at baseline correlating with longer overall survival in early-stage malignancies and lower levels predicting better prognosis in advanced stages. 6
Important Caveats
Multiple non-malignant factors influence CRP levels, including age, sex, race, body mass index, smoking, diet, sleep, and medication use. 1, 2
CRP values >10 mg/L are not always indicative of acute infection or malignancy alone—approximately 20% may be associated with smoking behavior and other lifestyle factors. 1
Single CRP measurements should be interpreted in clinical context rather than in isolation, as multiple conditions may coexist. 1, 3