Cancer risk in adult primary care patients with unexpected weight loss is generally very low, but for older male smokers with concurrent clinical features, it should trigger an "intensive" evaluation for cancer, according to a diagnostic accuracy study in the BMJ.
Using primary care records from England, researchers identified 63,973 adults with unexpected weight loss (mean loss of 5% or more in six months) during a 12-year period (2000-2012).
Of these, 37,215 (58.2%) were women, 33,167 (51.8%) were aged 60 years or older and 16,793 (26.3%) were ever smokers.
A total 908 (1.4%) had a diagnosis of cancer within six months of the index date, of whom 882 (97.1%) were aged 50 years or older. Lung cancer was most common (24.2% of diagnoses), followed by colorectal, gastroesophageal and pancreatic cancers.
The positive predictive value for cancer was above the 3 per cent threshold recommended by the National Institute for Health and Care Excellence (NICE) for urgent investigation in male ever smokers aged 50 years or older, but not in women at any age.
Ten additional clinical features were associated with cancer in men with unexpected weight loss, and 11 in women.
Positive likelihood ratios in men ranged from 1.86 (95% CI, 1.32-2.62) for non-cardiac chest pain to 6.10 (95% CI, 3.44-10.79) for abdominal mass, and in women from 1.62 (95% CI, 1.15-2.29) for back pain to 20.9 (95% CI, 10.7-40.9) for jaundice.
Abnormal blood test results associated with cancer included low albumin levels (4.67; 95% CI, 4.14-5.27) and raised values for platelets (4.57; 95% CI, 3.88-5.38), calcium (4.28; 95% CI, 3.05-6.02), total white cell count (3.76; 95% CI, 3.30-4.28) and C reactive protein (3.59; 95% CI, 3.31-3.89).
The researchers suggest consideration should be given to revising guidelines on cancer evaluation based on their findings.
Nicholson BD, Aveyard P, Price SJ, Hobbs FDR, Koshiaris C, Hamilton W. Prioritising primary care patients with unexpected weight loss for cancer investigation: diagnostic accuracy study. BMJ. 2020 August 13 [Epub ahead of print]. doi: 10.1136/bmj.m2651. Full text.
This article originally appeared on Univadis, part of the Medscape Professional Network.
