Predicting extracapsular extension of prostate cancer in men treated with radical prostatectomy: results from the population based prostate cancer outcomes study

PURPOSE

We investigated whether clinical information routinely available in community practice could predict extracapsular extension of clinically localized prostate cancer in men undergoing radical prostatectomy.

MATERIALS AND METHODS

We examined prostate cancer outcomes in a population based sample of 3,826 patients with primary prostate cancer in 6 regions of the United States covered by the Surveillance, Epidemiology, and End Results program. Stratified and weighted logistic regression was used to identify predictors of and probabilities for extracapsular extension of clinically localized tumors treated with radical prostatectomy.

RESULTS

Nearly 47% of men undergoing radical prostatectomy had extraprostatic extension. The strongest predictors were elevated prostate specific antigen (PSA) greater than 20 versus less than 4 ng./ml. (odds ratio 5.88, 95% confidence interval 2.90 to 11.15), Gleason score greater than 8 versus less than 6 (1.73, 1.04 to 2.87) and age greater than 70 versus less than 50 years (1.91, 0.98 to 3.70). Ethnicity and region were not associated with increased risk of extraprostatic extension. A nomogram developed from our model predicts extracapsular extension ranging from 24% in men younger than 50 years with PSA less than 4 ng./ml. and a Gleason score of less than 7 to 85% in those 70 years old or older with PSA greater than 20 ng./ml. and a Gleason score of 8 or more. If prostatectomy were limited to patients with less than 60% probability of extraprostatic extension based on the nomogram, 95% of those with organ confined cancers would undergo definitive surgery and 18% of those with extracapsular extension would be spared the morbidity of surgery.

CONCLUSIONS

In a population based analysis of prostate cancer practice patterns PSA, Gleason score and age are clinically useful predictors of extracapsular extension. Although extracapsular extension may be an imperfect predictor of cancer outcomes, our nomogram provides more realistic probabilities for extracapsular extension than those based on institutional series.

Geographic, age, and racial variation in the treatment of local/regional carcinoma of the prostate

PURPOSE

Prostate cancer is one of the most common cancers in men. Incidence rates increase with age and are substantially higher in black men than white men. This study examines the variations in the use of radical prostatectomy and radiation by geographic area, age, and race.

MATERIALS AND METHODS

Data from the National Cancer Institute's Surveillance, Epidemiology, and End-Results Program (SEER) were used to examine treatment differences. Current treatments generally consist of prostatectomy, radiation, or careful observation for clinically localized or regional disease.

RESULTS

The age-adjusted proportion of men, age 50 and older, who received radical prostatectomy increased sharply between 1984 and 1991, from 11.0% to 32.3% among men with local/regional disease. The choice of treatment varied widely by geographic regions. In 1991, the proportion that received prostatectomy was highest in Utah (47.8%) and lowest in Connecticut (22.5%) among men with localized and regional disease. The increase in radical prostatectomy was not limited to younger men. Although the rates increased for blacks, black men had lower age-adjusted rates of prostatectomy than whites in all years of the study.

CONCLUSION

The SEER data show a clear trend toward more aggressive treatment, especially prostatectomy. However, the proportion of black men who received prostatectomy was substantially lower than that of white men and this disparity does not appear to be changing.

Radiation dose and breast cancer risk in patients treated for cancer of the cervix

The relationship between breast cancer and radiation treatment for cervical cancer was evaluated in an international study of 953 women who subsequently developed breast cancer and 1,806 matched controls. Radiation doses to the breast (average 0.31 Gy) and ovaries (average 32 Gy) were reconstructed for exposed subjects on the basis of their original radiotherapy records. Overall, 88% of the breast cancer cases and 89% of the controls received radiation treatment [relative risk (RR) = 0.88; 95% confidence interval (CI) = 0.7-1.2]. Among women with intact ovaries (561 cases, 1,037 controls), radiotherapy was linked to a significant 35% reduction in breast cancer risk, attributable in all likelihood to the cessation of ovarian function. Ovarian doses of 6 Gy were sufficient to reduce breast cancer risk but larger doses did not reduce risk further. This saturation-type response is probably due to the killing of a critical number of ovarian cells. Cervical cancer patients without ovaries (145 cases, 284 controls) were analyzed separately because such women are at especially low natural risk for breast cancer development. In theory, any effect of low-dose breast exposure, received incidentally during treatment for cervical cancer, should be more readily detectable. Among women without ovaries, there was a slight increase in breast cancer risk (RR = 1.07; 95% CI = 0.6-2.0), and a suggestion of a dose response with the RR being 1.0, 0.7, 1.5 and 3.1 for breast doses of 0, 0.01-0.24, 0.25-0.49 and 0.50+ Gy, respectively. However, this trend of increasing RR was not statistically significant. If low-dose radiation increases the risk of breast cancer among women over age 40 years, it appears that the risk is much lower than would be predicted from studies of younger women exposed to higher doses.