****JavaScript based drop down DHTML menu generated by NavStudio. (OpenCube Inc. - http://www.opencube.com)****
|
Prediction tools, Partin tables, Nomograms
Partin Tables
Partin tables, which were developed by urologists Alan W. Partin and Patrick C. Walsh, are mathematical models that make predictions about what physicians might find during surgery to remove the prostate (also known as radical prostatectomy). Partin and Walsh knew that the clinical stage of a man's prostate cancer-the stage assigned before surgery-was often different from the actual, pathological stage-the stage determined after the prostate and the pelvic lymph nodes had been removed and examined under the microscope for cancer. They developed Partin tables to make better predictions about the pathological stage of each man's prostate cancer, so patients and their medical teams could have some help in assessing treatment options.
These tables correlate three things that doctors can determine about a man's prostate cancer before surgery: PSA level, Gleason Score, and Clinical Stage. The tables then statistically correlate these three factors to estimate the likelihood of the cancer's spread. (Remember that certain treatments, such as surgery, are much less effective when prostate cancer has spread beyond the prostate, so these predictions can help doctors and patients decide upon treatment options.)
Partin tables have been updated, and they now calculate probability percentages for the following four possibilities:
The cancer is confined to the prostate.
The cancer has extended into and perhaps through the capsule of the prostate gland (called Extraprostatic Extension).
The cancer has spread to the seminal vesicles.
The cancer has spread to the lymph nodes or beyond.
Notice that the table presents statistical possibilities. Although mathematics are used and the Partin tables are based on data from hundreds of patients who have been treated for prostate cancer, they remain educated guesses about the actual situation of a man who has been diagnosed with prostate cancer.
To show you how these tables work, we present four hypothetical cases below. You can, however, visit the website of the James Buchanan Brady Urological Institute at Johns Hopkins to make your own calculations and to find more information on Partin tables .
Nomograms
Nomograms, like Partin tables, are special mathematical models used to assess the risk that prostate cancer has spread to the lymph nodes, among other things. The most famous of these are the Kattan nomograms developed by biostatistician Dr. Michael Kattan at the Memorial Sloan-Kettering Cancer Center in New York. These can be accessed online, free of charge.
The prostate pre-treatment nomogram uses a patient's PSA level, Gleason scores, clinical stage of the tumour, prescribed radiation dose, and other information about hormone or radiation treatments to calculate the percentage likelihood of seven different factors:
- Whether the disease is confined to the prostate
- Whether the disease has spread into and perhaps through the capsule of the prostate
- Whether the disease has spread to the seminal vesicles
- Whether the disease has spread to the lymph nodes
- The probability of being cancer free 5 years after radical prostatectomy surgery
- The probability of being cancer free 5 years after external beam radiation therapy
- The probability of being cancer free 5 years after brachytherapy
There is also a nomogram calculating 2-year to 7-year cancer free probability after a radical prostatectomy, given the results of the surgical pathology report. And another nomogram calculates survival probability for patients with hormone refractory prostate cancer.
To give you an idea of how these calculation tools work, we have reproduced the calculations for three hypothetical patients in the tables below.
As you can see, nomograms force you to pull together a great deal of information about your cancer. Even if you decide not to use these calculation tools, it is useful for you to understand and discuss these diagnostic factors with your medical team. To help you gather information about your cancer, you might consider using two worksheets provided by the Memorial Sloan-Kettering Medical Center:
The Pre-Treatment Prostate Cancer Nomogram Worksheet
The Post-Treatment Prostate Cancer Nomogram Worksheet
There are other nomograms that might prove useful when making decisions about treatment. These include nomograms for calculating prostate volume and density, general life expectancy, and PSA doubling time.
|
