All cancer patients, for better or worse, are confronted with a prognosis from their doctors. A prognosis serves as a prediction of how the illness is expected to progress over time. It may also include how different treatment methods may affect survival. For those that are confronted with a fatal type of cancer, an end-of-life prognosis also estimates how long a patient can expect to survive.
However, just because a doctor suggests a survival time of 6 months, 1 year or whatever, that does not mean patients necessarily need to start counting down the days. Though an end-of-life prognosis can provide a good estimate of survival time, it is important to understand the data and downfalls associated with where these numbers come from.
A prognosis is based on how a patient’s particular type of cancer has advanced in past patients. Since 1973, the National Cancer Registry has painstakingly tracked survival statistics and treatment effectiveness for all types of cancers. From this vast mountain of data, means and averages for survival can be culled.
While data collection and number crunching are both extensive, the process is not without its flaws. For example, many prognoses are based purely on a single variable, most likely the stage of cancer progression. However, there are multiple variables that can affect survival time, including histology of the tumor, how early the cancer was detected, attempted treatments and age/general health of the patient. These facts are sometimes not taken into account when collecting data.
With this in mind, cancer patients are encouraged to ask doctors what factors were considered when determining their prognoses. Even when patients are further broken down into smaller subgroups, patients need to be aware of what exactly a prognosis means.
Most doctors hand down a prognosis that aligns with the median survival time of past cases of the patient’s particular cancer. Therefore, if a median survival time for a type of cancer is 1 year, that means half of all patients survived less than 1 year. In contrast, half of all patients also survived longer than 1 year. In some cases, patients survive significantly longer than the median average.
Another issue at hand is a doctor’s general inclination to not want to be overly optimistic about survival. This may lead him or her to offer conservative estimates in relation to an end-of-life prognosis. To counter this, patients may wish to talk to their oncologists about the probabilities of survival over different ranges of times.