Overtreatment and active surveillance in older men – a computer simulation

This study created a computer simulation of prostate cancer that calculates the risk of overtreatment in older men. Authors concluded that individual characteristics such as age, number of medical conditions, and cancer stage at diagnosis affect the probability of overtreatment and the potential benefit of active treatment.

Advances in early detection have led to a growing number of men living with low-risk prostate cancer. For many patients, low-risk prostate cancer either never requires treatment, or treatment can be delayed for a prolonged period. Active surveillance refers to actively monitoring tumor growth without actually administering treatment. The main aim is to reduce overtreatment. This is particularly important for older men, who may not always tolerate active treatment. However, older men are also more likely to be overdiagnosed. It has been estimated that 9 to 50% of men aged between 65 and 69 years are classified into a higher-risk disease category than needed. Overdiagnosis increases the likelihood of overtreatment.

The aim of this study was to create a computer simulation of prostate cancer that calculates the risk of overtreatment in older men.

Real data from prostate cancer medical databases was used to simulate three groups of 5 million men aged between 66 and 72 years with prostate cancer. The groups were divided according to how many additional medical conditions the men had. The computer model used factors such as age, cancer stage, screening history (number of tests done), and general health to calculate the risk of overtreatment.

Cancer stage had a large effect on the probability of overtreatment. For men detected in a low-risk stage, overtreatment ranged from 61 to 86%. In contrast, for men detected in a high-risk stage overtreatment ranged from 11 to 51%. The potential benefit of active treatment (based on number of life years saved per person treated) was also significantly higher for men with high-risk disease.

The probability of overtreatment increased with age and number of medical conditions. The probability of overtreatment for men aged 70 years or less with intermediate-risk disease and no additional medical conditions ranged from 23 to 28%. However, this increased to 41 to 52% for men over the age of 70 with intermediate-risk disease and many additional medical conditions. The potential benefit of active treatment also decreased with age and number of medical conditions.

Active surveillance resulted in a large reduction of overtreatment. For instance, the risk of overtreatment reduced from 61 to 37% for men with low-risk disease aged 66 years with no additional medical conditions. For intermediate-risk men aged 66 years and no additional medical conditions, overtreatment reduced from 23 to 16%. The risk of mortality due to prostate cancer mortality increased from 5 to 10%. The reduction in overtreatment became more pronounced with higher age and more medical conditions.

Authors concluded that individual characteristics such as age, number of medical conditions, and cancer stage at diagnosis affect the probability of overtreatment and the potential benefit of active treatment.

Not all possible factors can be taken into account in a computer simulation (such as patient preference, quality of life, results from a wider number of cancer tests). This is therefore a simplification of the natural history of prostate cancer.