Surgery v Radiation in Prostate Cancer

Prasanna Sooriakumaran MD PhD&

Peter Wiklund MD PhD

Background

• Comparative series so far suggest surgery may have improved oncologic outcomes over radiation

• Subject to non-comprehensive data and confounding by indication

• Lack of important covariates inc. comorbidity

• ProtecT results expected in 2016

Methods

• 34515 men, >98% capture of all men with prostate cancer in Sweden 1998 onwards

• Comprehensive dataset of all relevant covariates inc. patient and tumor factors due to linking National Prostate Cancer Register of Sweden to 8 other national registries

• Comprehensive and robust statistical modeling to adjust for baseline differences between surgery and radiation

Methods

• Fine & Gray competing risks analysis• Multivariable regression• Propensity score modeling• Inverse probability of treatment weights• Propensity score matching• Sensitivity analysis looking specifically for residual

confounding• Analysis stratified by year of treatment to look for

differential effects based on increasing radiation dose with time

Fig 1 Cumulative incidence function estimates of cancer specific and other cause mortality survival curves (n=34 515), stratified according to treatment type.

Sooriakumaran P et al. BMJ 2014;348:bmj.g1502

©2014 by British Medical Journal Publishing Group

Fig 2 Forest plot depicting propensity score adjusted subdistribution hazard ratios (sHR) for radiotherapy versus radical prostatectomy for cancer specific mortality stratified by risk group,

and substratified by age and Charlson comorbidity index score.

Sooriakumaran P et al. BMJ 2014;348:bmj.g1502

©2014 by British Medical Journal Publishing Group

Conclusions

• Surgery reduced risk of prostate cancer death in all localized prostate cancer risk groups

• Greatest benefit for surgery over radiation appeared in intermediate and high risk groups in men with long life expectancies

• Men with metastatic or micrometastatic disease did not benefit from one form of radical therapy over the other