C-reactive protein (CRP) is a substance produced by the liver. Its levels in the blood rise rapidly in response to inflammation, infection, or tissue injury throughout the body. CRP is an acute-phase reactant, meaning its concentration can increase significantly within hours of an inflammatory event. While it signals inflammation, CRP is a general marker and does not pinpoint its specific cause or location.
The Role of Inflammation and CRP in Cancer
Chronic inflammation is recognized as a factor in cancer development and progression. Tumors and their microenvironment can induce a persistent inflammatory response. This systemic inflammation prompts the liver to produce increased amounts of CRP.
CRP reflects this inflammatory state associated with malignancy. Cancer cells contribute to elevated CRP by releasing pro-inflammatory signaling molecules, such as interleukin-6 (IL-6), which stimulate CRP production in the liver. In some cancer types, elevated CRP can indicate increased disease activity or a higher tumor burden, signaling a pro-tumor environment.
Specific Cancers Associated with Elevated CRP
Elevated CRP levels are observed in various cancers, often reflecting the inflammatory burden imposed by the disease. These elevations are an association, not a diagnostic tool for specific cancers.
Colorectal cancer is frequently linked with high CRP levels, indicating disease extent, including potential liver metastasis or lymph node involvement. Lung cancer, particularly non-small cell lung cancer, often presents with elevated CRP, correlating with tumor progression. Pancreatic cancer also shows an association with increased CRP, reflecting its aggressive nature.
Gastric cancer patients commonly exhibit high CRP, related to advanced disease severity. Ovarian cancer may show elevated CRP, with higher levels sometimes associated with more advanced stages or treatment resistance. Kidney cancer, or renal cell carcinoma, often demonstrates elevated CRP levels that can correlate with tumor growth and patient outcomes.
Certain blood cancers, like lymphomas and multiple myeloma, are also associated with elevated CRP levels. While high CRP is observed in these cancers, it remains a general inflammatory marker and not a sole diagnostic criterion for any specific cancer type.
Understanding High CRP in Cancer
When an individual has already received a cancer diagnosis, an elevated CRP level can provide additional information. It functions as a prognostic marker, suggesting a less favorable outcome or more aggressive disease course. For example, persistently high CRP levels in patients with advanced cancers like breast cancer or prostate cancer may indicate a more challenging trajectory.
CRP levels can also be a tool for monitoring disease progression or response to treatment. If CRP levels decrease during therapy, it might suggest a positive response. Conversely, an increase in CRP could indicate disease progression or recurrence. It is important to interpret CRP results alongside other clinical data, such as imaging scans, specific tumor markers, and the patient’s overall health status.
Important Considerations for CRP Levels
C-reactive protein is a non-specific marker of inflammation, meaning many conditions other than cancer can cause its levels to rise. Common non-cancerous causes include bacterial or viral infections, autoimmune diseases like rheumatoid arthritis or lupus, and chronic inflammatory conditions such as inflammatory bowel disease.
Other factors like recent surgery, physical trauma, and obesity can also contribute to increased CRP levels. A high CRP level alone does not diagnose cancer, nor does it identify the specific cause of inflammation. A healthcare professional must always conduct further investigations to determine the underlying reason for elevated CRP, especially when cancer is suspected.