[Updated October 9, 2013]
Types of Predictive Calculators. In [Full text] [PMID: 19918337] Lowrance (papers) and Scardino (papers) discuss predictive models for prostate cancer covering methods that use risk classifications (e.g. d'Amico risk groups), tables (e.g. Partin tables), risk scores (e.g. CAPRA score), nomograms (e.g. Kattan nomograms)) and systems pathology which refers to using a wider range of variables than the traditional clinical variables (e.g. Aureon Labs' Px method). See [Table 1]. Future methods will likely incorporate genetic inputs to improve prediction accuracy. The authors point out that the need to discretize variables into a number of groups potentially reduces the accuracy of risk classifications, tables and risk scores whereas nomograms do not suffer from this problem (however, whether this potential loss of prediction accuracy is material is not discussed).
InterpretationCaution needs to be exercised in interpretation. For example, this article shows what can go wrong by incorrectly assuming that median life expectancy is the amount of time a particular person has left to live.
Comprehensive CalculatorsThere are two particularly comprehensive prostate cancer calculator sites plus a range of nomograms on a third site. The links to the first two are easy to remember since their links are nearly the same: http://www.nomogram.org (University of Montreal) and http://www.nomograms.org (Sloan Kettering). The Sloan Kettering site ends in "s" whereas the University of Montreal site does not. The Prostate Cancer Research Institute (PCRI) site contains 9 nomograms, i.e. charts that can be used like calculators.
A. Memorial Sloan Kettering Calculators. To access the Sloan Kettering online calculators go to http://www.nomograms.org and then click on Prostate in left hand column. That takes you to a new page and on that click on Open calculator in box in upper right. When new window appears click on "No". The following calculators are provided:
- Pretreatment calculator: Given PSA, Gleason Subscores, Stage & treatment get prob of disease involvement and disease free progression after 5 years for each of surgery, external radiation and seeds.
- Post treatment calculator: Given PSA, surgical margin and disease involvement get prob of disease free progression in 2, 5 and 7 years.
- Hormone refractory calculator: Given Age, Karnofsy PS, Heomglobin, PSA, LDH, Alkaline Phosphates and Albumin get 1 year, 2 year and median survival probabilities.
- Prostate Volume Calculator: Given dimensions & PSA calculate volume & PSA density.
- Life Expectancy: Given age and race calculate male life expectancy.
- PSA Doubling Time: Given series of dates and PSA values calculate doubling time, slope of log(PSA) vs. time curve and PSA velocity. This calculator does have the restriction that it cannot accept PSA values less than 0.1 which may be a problem if you are using an ultrasensitive PSA assay. In that case enter all your PSA values as 10x or 100x the real PSA value and the doubling time computed will still be correct.
- Before Diagnosis. There are 6 pre-biopsy calculators which can be used prior to biopsy to give the probability of biopsy results. The first is used if PSA is in the 0 - 2.5 ng/ml range, the second is for initial extended biopsy, the third is for extended repeat biopsy, the fourth is for saturation biopsy, the fifth is for 120 day mortability after biopsy based on a comorbidity score and the sixth is for initial sextant biopsy.
- Before Treatment I. There are calculators to predict the probability of Gleason sum upgrade, extra capsular extension, seminal vesicle invasion and lymph node invasion. (Regarding Gleason Score upgrading, note this 2008 paper on factors making Gleason Score upgrade more likely here: [PMID: 18207180] which finds that "A total of 134 patients (50%) were upgraded postoperatively to Gleason score 7 or higher. Preoperative prostate specific antigen greater than 5.0 ng/ml (p = 0.036), prostate weight 60 gm or less (p = 0.004) and more cancer volume at biopsy, defined by cancer involving greater than 5% of the biopsy tissue (p = 0.002), greater than 1 biopsy core (p is less than 0.001) or greater than 10% of any core (p = 0.014), were associated with pathological upgrading. Upgraded patients were more likely to have extraprostatic extension and positive surgical margins at radical prostatectomy (p is less than 0.001 and 0.001, respectively". A second 2008 paper [PMID: 18782303] concluded that "Men with a higher PSA level, perineural invasion and high-volume cancer at biopsy are most likely to be upgraded, while men with a large prostate volume and low-volume cancer at biopsy are more likely to be downgraded. These findings have implications for men with prostate cancer managed without confirmation by RP of their true GS.". Also [PMID: 18778348] concludes that " risk of upgrading is a function of two opposing contributions: (i) a more aggressive phenotype in smaller prostates and thus increased risk of upgrading; and (ii) more thorough sampling in smaller prostates and thus decreased risk of upgrading. When sampled more thoroughly, the phenotype association dominates and smaller prostates are linked with an increased risk of upgrading. In less thoroughly sampled prostates, these opposing factors nullify, resulting in no association between prostate size and risk of upgrading. These findings help to explain previously published disparate results of the importance of prostate size as a predictor of Gleason upgrading.") A 2011 paper by Corcoran et al [PMID: 21895937] analyzed 684 patients with Gleason 6 or 7 on biopsy and found that 50% were upgraded. The upgraded patients had tumors which had significantly smaller tumor volume suggesting that tumor volume can help in predicting an upgrade.
- Before Treatment II. There are calculators for calculating the probability of clinically insignificant prostate cancer, the probability of predominantly transition zone prostate cancer, probability of survival within 30 days of surgery and the probability of 10 year survival.
- After Surgery. There are post op calculators for the probability of PSA recurrence, Local recurrence, Distant recurrence and prostate cancer specific survival.
- After PSA Relapse. There are calculators for the probability of Metastatic progression, mortality for surgical patients undergoing subsequent hormone therapy and mortality after PSA relapse.
- Hormone Refractory Prostate Cancer. There is a calculator for the probability of survival for patients with androgen independent prostate cancer.
- Other. At the bottom of its calculators page the University of Montreal has doubling time and Life expectancy calculators.
- Blackberry Calculators. There are downloadable calculators for the Blackberry. See the May 29, 2010 news item on the New Features page.
C. Prostate Cancer Research Institute (PCRI). The PCRI has the following nomograms on its site:
- Probability of Extracapsular Extension
- Probability of Seminal Vesicle Involvement
- Probability of Lymph Node Involvement with Tumor
- Probability of Latent or Indolent Tumors of Low Biological Aggressiveness
- Probability of Metastases Five Years After 3D Conformal EBRT
- Probability of Being Disease-Free Five Years After Brachytherapy
- Probability of Median Survival in Castrate Refractory Patients
- Probability of an Abnormal Bone Scan
D. SWOP. A site with several calculators is the http://prostate-riskindicator.com/via.html site, also referred to as SWOP, of The Prostate Cancer Research Foundation is closely related to the Department of Urology of the Erasmus MC, University and Medical Centre of Rotterdam. It has a number of risk indicators. Quoting from the site: "Risk Calculator 1 – the general health calculator is a starting point, looking at family history, age and any medical problems with urination. Risk Calculator 2 – the PSA risk calculator looks at the levels of prostate specific antigen (PSA) in patient’s blood to help predict whether further investigation is required. Risk calculator 3 predicts the chance of a positive sextant biopsy in a man who has never been screened; and also assesses the degree of aggressiveness. Risk calculator 3 + DRE assessment predicts more accurately the chance of a positive sextant biopsy, compared to only assessing a patient’s PSA value (RC 2), but without the necessity of a TRUS. An additional feature is the prediction of a high grade or advanced prostate cancer. Risk calculator 4 is used for men who have previously had PSA screening, but have either had no biopsy or one that was negative. It predicts the chance of a positive sextant biopsy and its degree of aggressiveness. Risk calculator 4 + DRE provides additional information, without the necessity of a TRUS, for assessing men who have previously been screened, whether they have had a prior biopsy or not. It also predicts the chance of a positive outcome and whether that would be high grade or advanced. Risk calculator 5 calculates the chance of having indolent prostate cancer which may not require immediate treatment. Risk Calculator 6 is the latest in the series — it calculates a man’s future risk over the next four years, taking into account age, prostate-specific antigen, digital rectal examination, family history, prostate volume, and previous biopsy status."
Other Calculators. d'Amico Risk Categories. Although not a calculator, a useful classification is the d'Amico risk category stratifying disease into Low, Medium and High Risk. More is available in the third paragraph here.
Also check out these calculators:
Wolfram Alpha provides a box in which you enter a query and find out where among the population you stand on various medical tests, e.g. enter one of these:
psa 5 age 60
vitamin d 25 age 60 male
bmi 25 age 60 male
life expectancy age 60 male
blood pressure 125/75 age 60 male
ldl cholesterol 125 age 60 male
hdl cholesterol 50 age 60 male
or if you omit the test value then it gives the population reference range, e.g. enter:
psa age 60
There is a link to a life expectancy table from the US Social Security Administration (SSA) and an explanation of how to use it on page PROS-A (page 13 of the PDF document) of the NCCN Prostate Cancer Practice Guidelines. They recommend adjusting the ages in the actuarial table to reflect current health status. http://www.nccn.org/professionals/physician_gls/PDF/prostate.pdf
A direct link to the aforementioned SSA actuarial table is here. This table gives total expected lifetime for men of a given age. To get remaning lifetime subtract current lifetime from total lifetime. http://www.ssa.gov/OACT/STATS/table4c6.html
Page SAO-A (page 7 of the PDF document) of the NCCN Senior Adult Oncology Practice Guidelines contains a figure with remaining expected years of lifetime for each 5 year age group as well as upper and lower quartiles. This may be a bit easier to use since it directly gives the remaining lifetime and the quartiles can be used for patients in above average or below average health. http://www.nccn.org/professionals/physician_gls/PDF/senior.pdf The figure is based on [PMID: 11386931] .
You can calculate your Charleson co-morbidity score (higher numbers are
assigned to patients with overall poorer health) using this: Excel spreadsheet. Also see accompanying [Full Text[ [PMID: 15610554] paper.
Now that you have your Charlson score you can input that score into this nomogram which will give separate ten year life expectancies after surgery and after radiation treatment. Also see accompanying paper: [Full Text] [PMID: 17704404].
There are calculators and more info here: [Institute of Algorithmic Medicine Calculator] and here: [info] [Hall et al Calculator] and [Walz 2007]. Also see [PMID: 16770340] . This paper [PMID: 17979925] concluded that clinicians have an accuracy of less than 70% whereas Walz claims that his group's nomogram has an 84% accuracy on a validation sample.
Tumor Volume (cc) = 3.476 + 0.302 x PSA
Tumor Volume (%) = 11.331 + 0.704 x PSA