I’m Always Searching for Good Statistical Tools
I don’t know about other prostate cancer survivors but, as a 7-1/2 survivor, I’m keenly interested in survival statistics and potential recurrence-prevention strategies. Five-year survival statistics don’t have much value for me.
The following lengthy article, published recently in the Journal of Urology, provides what seems to be a good tool for estimating 15-year survival. Fortunately, my accidental diagnosis caught my disease when the Gleason was 3+3 and completely organ confined which, according to this article, give me a better than 97% chance of surviving for 15 years. That’s good news.
The Critical Importance of Early Detection
The tables in the article clearly show a significant decline in survivability associated with the more advances stages of the disease. I continue to believe that all men should begin PSA testing at age 35 to establish a baseline PSA value, and then monitor that value every year. Online PSA tests are available at a number of sources, including Bloodtestathome.com.
I, of course, would like to extend my survival period for as long as possible, which is why I implemented my semi-vegetarian eating and exercise regime following my surgery. You can follow my cycling program here or over at theMyBikeInfo and Black Tire Affair blogs. ACS research indicates that one-third of all cancers are related to poor diet and exercise. These are variables I can control, so I work on them pretty diligently – but not without the occasional fall from the wagon:-)
New Prostate Cancer Info Link
I received this article through a LinkedIn prostate cancer group posting. You can find the original at the New Prostate Cancer Infolink website or in the Journal of Oncology.
For several years we have been able to use the Kattan nomograms to project 5-, 7-, and 10-year recurrence-free survival before and after radical prostatectomy for localized prostate cancer, based on the patient’s age, stage, Gleason score, and other relevant data (associated with biopsy or surgical findings, as appropriate).
In a new paper, just published on line in the Journal of Urology, Eggener et al. have now published data that will help us to be able to predict 15-year disease-specific survival in men undergoing radical prostatectomy for localized prostate cancer.
In the same manner as prior risk projections developed by Kattan and his colleagues, this set of projections is based on a sophisticated risk regression analysis modeled using clinical, pathological, and long-term outcomes data from 11,521 patients treated by radical prostatectomy at four major academic centers between 1987 and 2005. The model was then validated using similar data on 12,389 other patients treated at a separate institution during the same time period. The average (median) follow-up of the real patients in the modeling cohort was 56 months (nearly 5 years) and 96 months (8 years) in the validation cohort.
Eggener et al. were able to show that:
- Overall 15-year prostate cancer specific mortality (PCSM) in the modeling cohort was 7 percent.
- Statistically significant predictors of PCSM were
- Primary and secondary Gleason grade 4 or 5 (each p <0.001)
- Seminal vesicle invasion (p <0.001)
- Year of surgery (p = 0.002)
- Only 3 of 9,557 patients (0.03 percent) with organ-confined prostate cancer and a pathological Gleason score of 6 or less actually died of prostate cancer post-surgery.
Based on these data, they have developed a nomogram that is capable of predicting 15-year PCSM which was accurate and highly discriminating when tested in the validation cohort of patients.
When patients are stratified by age at diagnosis, the nomogram predicts 15-year PCSM rates as follows:
- For men with a pathological Gleason score 6 or less — 0.2 to 1.2 percent
- For men with a pathological Gleason score of 3 + 4 = 7 — 4.2 to 6.5 percent
- For men with a pathological Gleason score of 4 + 3 = 7 — 6.6 to 11.0 percent
- For men with a pathological Gleason score of between 8 and 10 — 26.0 to 37 percent.
- For men with organ-confined disease — 0.8 to 1.5 percent
- For men with extraprostatic extension — 2.9 to 10.0 percent
- For men with seminal vesicle invasion — 15.0 to 27.0 percent
- For men with lymph node metastasis — 22.0 to 30.0 percent
The authors conclude that, “The prostate cancer specific mortality risk can be predicted with remarkable accuracy after the pathological features of prostate cancer are known” and that poorly differentiated cancer and seminal vesicle invasion are the prime determinants of PCSM after radical prostatectomy.
While it is fair to say that there are no real surprises in these data, based on cohorts of patients treated at some of the very best academic centers in the U.S.A., it will certainly add to the quality of the Kattan nomograms when these data can actually be built into the on-line prognostic tools available on the Memorial Sloan-Kettering web site.