The changing face of prostate cancer in British Columbia 1988-2000.

OBJECTIVE

To evaluate changes of prostate cancer incidence, referrals, stage, treatment and outcomes delivered in British Columbia since the 1980's.

MATERIALS AND METHODS

Examination of the BC Provincial Tumour Registry, BC Cancer Agency (BCCA) and BC Medical Services Plan databases.

RESULTS

The number of incident cases increased linearly from 1980 through 1990. Between 1991 and 1995 a harvesting effect was seen due to unofficial PSA screening, balanced by a post-harvest effect between 1995 and 1998. Since 1999 the incidence has resumed the linear trend extrapolated from the 1980's. The age-standardised incidence rate has recently risen in younger (<65yrs) men. The incidence of metastatic cancer has dropped from 14% of cases referred to the BCCA in 1988 to 3.5% in 2000. A steady proportionate increase in T1 and T2 referrals has occurred since 1988. PSA levels at referral are lower (mean PSA 10 nmol/L in 2000 versus 15 nmol/L in 1990. Gleason scores are higher, likely reflecting changes of interpretation of pathological grade. The number of men receiving any curative therapy has increased from 43% in 1990 to 53% by 1999, and the proportion treated with surgery has increased from 30% in 1990 to 50% by 2000. Mortality rates have been falling since 1991, and BC has the lowest mortality rate in Canada.

CONCLUSIONS

Predictions of incidence have been beset by unanticipated external factors, and have underestimated actual incidence. Stage migration towards better prognosis tumours occurring in younger men has led to the increased use of surgery and brachytherapy and decreased use of external radiation.