Clinical features of metastatic cancer in primary care; a case-control study using medical records

The problem

The clinical features of metastatic cancer in primary care are largely unknown.

The approach

This was a case-control study in eleven general practices in Devon, UK, identifying symptoms, signs and laboratory test abnormalities in the year before metastasis in patients with a previous breast, colorectal or prostate cancer. Two control groups were: patients with the same primary cancer (‘cancer' controls), but without metastases, and age, sex and practice matched controls without cancer (‘healthy' controls). The primary analysis used conditional logistic regression.

Findings

We studied 162 cases, 152 ‘cancer' controls and 145 ‘healthy' controls. Relatively common symptoms associated with cancer were: vomiting, in 40 (25%) cases and 13 (9%) cancer controls, multivariable odds ratio (OR) 3.5 (95% confidence interval 1.3,9.4), p=0.011; low back pain, 28(24%) and 17(11%) respectively, OR 2.5(1.1,5.6), p=0.032; loss of appetite, 32 (20%) and 9 (6%), OR 4.0 (1.2,13.2), p=0.021; and shoulder pain 27 (17%) and 8 (5%), OR 5.3(1.6, 18), p=0.007. Groin pain was infrequent, but was strongly associated, 16 (10%) and 1(1%) respectively, OR 10 (1.2, 82), p=0.032, as was pleural disease 9 (6%) and 1(1%), OR 10 (1.1,92), p=0.038. Symptom reporting was less in ‘healthy' controls than cancer controls.

Consequences

All the features of disseminated cancer have been reported before in secondary care series, but the relative infrequency of specific symptoms - such as local pain - and relative commonness of non-specific symptoms, such as vomiting and loss of appetite is an important finding. This may explain - in part at least - delays in the diagnosis of metastases.

Credits

• Jacqueline Barrett, University of Oxford, Oxford, UK
• Peter Rose, University of Bristol, Bristol, UK
• Sally Stapley, University of Oxford, Oxford, UK
• Debbie Sharp
• Willie Hamilton, University of Oxford, Oxford, UK