Understanding ESR Levels in Cancer Patients
Elevated erythrocyte sedimentation rate (ESR) levels are often observed in cancer patients. This is due to the body's inflammatory response to the disease. However, ESR is not a specific marker for cancer and can be influenced by other conditions as well. Regular monitoring of ESR levels can provide valuable insights into the patient's overall health and response to treatment.
What is ESR?
The erythrocyte sedimentation rate (ESR), which may be referred to as “sedimentation rate” or “sed rate” for short, is a simple laboratory test used to indicate approximate levels of inflammation within the body. Higher ESR levels typically indicate increased inflammation within the body, which may be a sign of an underlying disease [1]. During inflammation, there is an increase in the production of proteins (such as cytokines, complement proteins, and chemokines) in the blood. These proteins cause red blood cells to clump together in stacks, which increases their density and leads to faster sedimentation rates [1]. For this reason, higher ESR rates are a useful marker of systemic inflammation.
How is ESR measured?
The most commonly used method to measure ESR is called the Westergreen method. The Westergreen method is a simple procedure comprising three steps: first, a phlebotomist performs a basic venous blood draw. The blood sample is collected into a vacuum-sealed tube containing an anticoagulant such as sodium citrate or EDTA [1]. This sample is then sent to a laboratory, where it is transferred into a vertical test tube called a Westergreen tube [1]. The blood sample is allowed to sit for one hour to allow time for red blood cells to settle to the bottom of the tube. This process leaves a portion of plasma sitting on top of the red blood cells, and the quantity of plasma can be measured in millimeters. The greater the quantity of plasma after 1 hour, the faster the rate of erythrocyte sedimentation. Thus, the ESR is reported in units of millimeters [of plasma] per hour [1].
Measuring ESR is important because it plays a critical role in the diagnosis and follow-up of various inflammatory and noninflammatory conditions. It is commonly used to assess the acute phase response, which is the body's immediate response to tissue injury or infection [2]. Specifically, ESR is useful in diagnosing and monitoring inflammatory conditions such as rheumatoid arthritis, temporal arteritis, and certain infections. For instance, 90% of patients who have serious orthopedic infections demonstrate elevated ESR levels, making ESR a sensitive measure of the inflammatory response in these conditions [3]. That being said, it is important to remember that ESR is a non-specific indicator of inflammation and therefore cannot be used to diagnose specific health conditions. Rather, ESR is a helpful first step towards securing a more precise diagnosis via additional tests.
Why are ESR levels important in cancer patients?
Elevated ESR levels have been observed in various types of cancer, including cutaneous melanoma, prostate cancer, and colorectal cancer [2, 3, 4, 5]. In particular, extremely high ESR levels (greater than 100 mm/hr) have been observed in cases of multiple myeloma, lymphoplasmacytic lymphoma, and various metastatic tumors [1]. The correlation between ESR levels and tumor metastasis makes ESR a useful measure for monitoring cancer progression. High ESR generally correlates with poor prognosis, particularly in cancers such as breast, prostate, colorectal, Hodgkin lymphoma, and chronic lymphocytic leukemia [1].
What do abnormal ESR levels indicate?
ESR levels and cancer
In general, significant elevation of ESR tends to indicate the presence of an inflammatory condition and/or underlying disease. Extremely high ESR levels may indicate cases of occult or undiagnosed cancer, prompting physicians to pursue further diagnostic testing [2].
ESR levels are useful not only for cancer diagnosis, but can also be informative for prognosis in patients with known cases of cancer. For example, extreme elevations in ESR in patients with cutaneous melanoma have been associated with metastasis and poorer survival outcomes [3]. In colorectal cancer, higher ESR rates have also been associated with advanced disease and poorer survival following surgery [4]. High ESR in patients with prostate cancer has also been used to predict tumor malignancy and overall survival [5]. It is worth clarifying that such correlations are statistical and cannot provide definitive prognoses for individual patients. Therefore, while ESR might be a useful predictive tool for generating prognoses, it should always be interpreted within the context of other clinical findings and considerations.
Conclusion
Erythrocyte sedimentation rate (ESR) is a measure of how quickly red blood cells accumulate and settle at the bottom of a test tube. ESR can be measured using a simple and inexpensive laboratory procedure known as the Westergreen method and is often used to assess levels of systemic inflammation. Monitoring ESR levels is important in patients with certain types of cancer, such as cutaneous melanoma, as extreme elevations in ESR have been correlated with metastatic disease and poorer prognosis. However, ESR is an indirect and generalized measure of inflammation and therefore cannot provide detailed information about disease identity or progression. Overall, ESR is a useful clinical measure when used in the context of other diagnostic and prognostic tools and may help guide the treatment decisions of clinicians and oncologists.
