Appropriate Description of Probability Distribution of Prostate Specific Antigen (PSA): An Aid to Early Detection of Prostate Cancer

Abstract

Prostate cancer has been observed to be a worrisome ailment among adult males across the globe over some decades. Just like any other ailment, its early detection and treatment gives the patient a better chance of survival. Measuring the Prostate specific antigen (PSA) of the patients at specified intervals is one of the techniques of detecting the onset of prostate cancer. This paper attempts to obtain the most appropriate probability distribution of prostrate specific antigens (PSA) that gives the best estimates of the parameters of the distribution. The age specific probabilities of patients with prostate specific antigen (PSA)>4.0ng/ml were calculated. The results show that the most appropriate distribution among the distributions fitted is the Burr distribution. The probability of observing a PSA greater than 4.0 ng/ml in adult males above the age of 45 years was seen to be moderately high (0.68) with a median PSA of 8.30 ng/ml and an inter quartile range of 16.40. The results also show that PSA of 60.0 ng/ml and above were exceptional cases that require urgent attention. It was observed that men whose ages are between 60 and 80 years have higher chances of having PSA values greater 4.0ng/ml with men between 60 and 75 years having the highest chances. It is therefore suggested that men with PSA higher than 4.0ng/ml between 60 and 80 years of age may not be subjected to needle biopsies but be referred directly for digital rectal examinations.