Clinical features of prostate cancer before diagnosis: a population-based, case-control study.
BACKGROUND
Even in areas where screening is available, many prostate cancers are diagnosed after the symptoms begin. However, the risk posed by particular symptoms is largely unknown, especially in unselected populations such as primary care.


OBJECTIVE
To identify and quantify the features of prostate cancer before diagnosis, both individually and in combination.


METHODS
Population-based case-control study.


METHODS
All 21 general practices in Exeter, Devon, UK.


METHODS
We studied all 217 prostate cancer patients diagnosed between 1998 and 2002, and 1080 male controls, matched by age and general practice. The full medical record for 2 years before diagnosis was coded, using the International Classification of Primary Care. We calculated odds ratios for variables independently associated with cancer, using conditional logistic regression, and calculated the positive predictive values for these, both individually and in combination.


RESULTS
Eight features were associated with prostate cancer before diagnosis. Their positive predictive values against a background risk of 0.35% were: urinary retention 3.1% (95% confidence interval [CI] = 1.5 to 6.0); impotence 3.0% (95% CI = 1.7 to 4.9); frequency 2.2% (95% CI = 1.3 to 3.5); hesitancy 3.0% (95% CI = 1.5 to 5.5); nocturia 2.2% (95% CI = 1.2 to 3.6); haematuria 1.0% (95% CI = 0.57 to 1.8); weight loss 0.75% (95% CI = 0.38 to 1.4); abnormal rectal examination, deemed benign 2.8% (95% CI = 1.6 to 4.6); abnormal rectal examination, deemed malignant 12% (95% CI = 5.0 to 37): all P <0.001, except for hesitancy P = 0.032, nocturia P = 0.004 and haematuria P = 0.009. Loss of weight, impotence, frequency and abnormal rectal examination remained associated with cancer after excluding the final 180 days from analysis.


CONCLUSIONS
Most men with prostate cancer present with symptoms. The predictive values for these symptoms will help guide GPs and patients about the value of further investigation.
Hamilton
William
W
Department of Community Based Medicine, University of Bristol, The Grange, 1 Woodland Road, Bristol BS8 1AU. w.hamilton@bristol.ac.uk
Sharp
Deborah J
DJ
Peters
Tim J
TJ
Round
Alison P
AP
D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D051517:Digital Rectal Examination; D042241:Early Diagnosis; D007172:Erectile Dysfunction / Q000150:complications; D005194:Family Practice; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000150:complications* / Q000175:diagnosis; D053448:Prostatism / Q000150:complications; D012017:Referral and Consultation; D015431:Weight Loss
D017430:Prostate-Specific Antigen