Rectal bleeding in men and women over 75, a change in bowel habit in men over 60, and iron deficiency anaemia in various groups were identified as predictive of gastrointestinal cancer in at least 5% of cases.
Macroscopic haematuria in men and women over 60 was predictive of urological cancer, and a malignant-feeling prostate on rectal examination in men over 40 was predictive of prostate cancer.
Haemoptysis in men over 55 and women over 65 and dysphagia in men over 55 were predictive of lung and oesophageal cancer respectively.
Breast lumps in women over 20 were predictive of breast cancer, and postmenopausal bleeding was predictive of gynaecological cancer in women aged 75 to 84.
The research, to be published in the British Journal of General Practice, was a meta-analysis of 12 existing studies.