In this paper, we are presenting a new architecture to directly compute the ‘Percent-free PSA’ diagnostics index to enhance the differentiation of prostate cancer from benign prostatic disease. The proposed circuit uses silicon nanowires-based memristive biosensors by implementing a combination of sensing and computing carried out inside the sensing architecture and not near the sensor. These types of biosensor configurations that are able to directly provide the desired result without any intermediate operations can open up a new branch of research in the area of in-memory sensing and edge computing.