Blood test trends linked to cancer diagnoses after unexplained weight loss

In a retrospective cohort study of more than 275,000 patients with unexplained weight loss, changes over time in 26 routine blood tests were associated with subsequent cancer diagnoses. Overall, 23 blood-test trends were associated with cancer risk, and after accounting for age and sex, several trends were more discriminative for cancer diagnosis than abnormalities identified by a single test. The observational findings suggest that longitudinal results may help primary-care clinicians prioritize patients for additional cancer testing, but they do not establish whether such testing improves clinical outcomes.

The study, led by Brian Nicholson and colleagues at the University of Oxford and published in PLOS Medicine on September 17, evaluated whether changes in routinely measured blood-test results could improve cancer-risk stratification among people with unexplained weight loss. The researchers compared abnormalities on individual tests with trends across repeated measurements. Nearly 14,000 participants were subsequently diagnosed with cancer within six months, allowing the investigators to examine relationships between single-test abnormalities, longitudinal trends and cancer diagnosis.

Abnormal results such as low hemoglobin or increased platelet counts can provide clues about a patient’s cancer risk, the research team noted. However, monitoring trends over repeat tests can reveal changes that do not appear abnormal when considered in isolation. By considering patient age and sex alongside patterns in repeated blood-test results, the investigators found that some trends were more discriminative for cancer diagnosis than individual abnormal values. Among the 23 trends associated with overall cancer risk, white blood cell count and neutrophil trends were linked to lung cancer, while trends in red blood cell count, hematocrit and the platelet-to-lymphocyte ratio were associated with prostate cancer. Other abnormalities were also associated with specific cancer types.

Study author Brian Nicholson said the analysis showed how adding age and sex can make blood-test results more accurate for assessing cancer risk. He said the relatively simple calculation could be performed at the laboratory. Study author Pradeep Virdee noted that monitoring how a patient’s blood-test results change over time could offer further value in some instances. The researchers plan to assess how well blood-test abnormalities and trends inform cancer risk in patients with other nonspecific symptoms, such as fatigue and vomiting. The current results are bounded to the studied population of patients with unexplained weight loss, and most participants were not diagnosed with cancer. Because the work was observational, it shows associations with diagnosis rather than proving that trend-guided testing leads to earlier cancer detection, better survival or fewer unnecessary investigations.

Subject of Research: Longitudinal routine blood-test trends and cancer diagnosis in patients with unexplained weight loss

Article Title: Blood test trends may help identify patients at increased risk of cancer

Article References: Blood test trends may help identify patients at increased risk of cancer. Original publication (Bibliographic details unavailable.)

Image Credits: AI Generated

DOI: Not provided

Keywords: blood test trends, cancer diagnosis, unexplained weight loss, risk stratification, primary care, retrospective cohort, longitudinal data, PLOS Medicine, Blood, test, trends, help