RETRACTED: Prioritising primary care patients with unexpected weight loss for cancer investigation: diagnostic accuracy study

Abstract

Objective To quantify the predictive value of unexpected weight loss (WL) for cancer according to patient’s age, sex, smoking status, and concurrent clinical features (symptoms, signs, and abnormal blood test results). Design Diagnostic accuracy study. Setting Clinical Practice Research Datalink electronic health records data linked to the National Cancer Registration and Analysis Service in primary care, England. Participants 63 973 adults (≥18 years) with a code for unexpected WL from 1 January 2000 to 31 December 2012. Main outcome measures Cancer diagnosis in the six months after the earliest weight loss code (index date). Codes for additional clinical features were identified in the three months before to one month after the index date. Diagnostic accuracy measures included positive and negative likelihood ratios, positive predictive values, and diagnostic odds ratios. Results Of 63 973 adults with unexpected WL, 37 215 (58.2%) were women, 33 167 (51.8%) were aged 60 years or older, and 16 793 (26.3%) were ever smokers. 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. The positive predictive value for cancer was above the 3% threshold recommended by the National Institute for Health and Care Excellence for urgent investigation in male ever smokers aged 50 years or older, but not in women at any age. 10 additional clinical features were associated with cancer in men with unexpected WL, and 11 in women. Positive likelihood ratios in men ranged from 1.86 (95% confidence interval 1.32 to 2.62) for non-cardiac chest pain to 6.10 (3.44 to 10.79) for abdominal mass, and in women from 1.62 (1.15 to 2.29) for back pain to 20.9 (10.7 to 40.9) for jaundice. Abnormal blood test results associated with cancer included low albumin levels (4.67, 4.14 to 5.27) and raised values for platelets (4.57, 3.88 to 5.38), calcium (4.28, 3.05 to 6.02), total white cell count (3.76, 3.30 to 4.28), and C reactive protein (3.59, 3.31 to 3.89). However, no normal blood test result in isolation ruled out cancer. Clinical features co-occurring with unexpected WL were associated with multiple cancer sites. Conclusion The risk of cancer in adults with unexpected WL presenting to primary care is 2% or less and does not merit investigation under current UK guidelines. However, in male ever smokers aged 50 years or older and in patients with concurrent clinical features, the risk of cancer warrants referral for invasive investigation. Clinical features typically associated with specific cancer sites are markers of several cancer types when they occur with unexpected WL.

Individual inflammatory marker abnormalities or inflammatory marker scores to identify primary care patients with unexpected weight loss for cancer investigation?

“…These codes equate to a mean weight loss of 5% or more within a 6-month period. 6 All patients had the following inflammatory markers recorded in the 3 months before to 1 month after the index date: albumin, CRP, lymphocyte count (LC), neutrophil count (NC) and platelet count (PC). We excluded patients with evidence of a past cancer diagnosis or a WL intervention within the previous six months.…”

“…Cancer risk rises above 3% when adults with unexpected WL also have low albumin or a raised white cell count, calcium, platelets or inflammatory markers. 6 The aim of this study was to investigate whether inflammatory marker scores could be used to select patients with unexpected WL for further cancer investigation in preference to individual inflammatory marker abnormalities.…”

Combining simple blood tests to identify primary care patients with unexpected weight loss for cancer investigation: Clinical risk score development, internal validation, and net benefit analysis

“…This association is greatest in males once aged 60 years or older and in females 80 years or older [ 2 , 3 ]. Current investigation guidelines focus on selecting patients for single-site cancer investigation based on simple combinations of clinical features (individual risk factors, signs, symptoms, and blood test abnormalities) [ 3 – 5 ].…”

“…As most patients presenting to primary care with UWL will not have cancer, diagnostic strategies that avoid the harms of unnecessary invasive and costly investigation are also required for patients at a low risk of cancer [ 1 ]. Our previous work has shown that the presence of individual co-occurring clinical features increases the likelihood of cancer sufficiently to rule-in cancer investigation [ 5 ]. However, the absence of individual co-occurring clinical features, including pairs of normal inflammatory markers, do not reduce the likelihood of cancer sufficiently enough to rule-out patients from further cancer investigations [ 5 , 6 ].…”

“…Our previous work has shown that the presence of individual co-occurring clinical features increases the likelihood of cancer sufficiently to rule-in cancer investigation [ 5 ]. However, the absence of individual co-occurring clinical features, including pairs of normal inflammatory markers, do not reduce the likelihood of cancer sufficiently enough to rule-out patients from further cancer investigations [ 5 , 6 ]. Primary care clinicians commonly request multiple blood tests when patients present with UWL [ 5 , 7 ].…”