DRE and PSA test work together in prostate cancer screening


Dear Doctors: I am 84 years old and just got a new doctor. When I asked her about the prostate exam my previous doctor did every few years, she seemed dismissive, saying, “Oh, we don't do that anymore.” Is this a personal choice by the physician? I worry about missing an important diagnosis.

Dear Reader: The exam you are referring to is known as a digital rectal exam, or DRE. In men, it is used to examine the prostate gland. The prostate, which supplies seminal fluid, is part of the male reproductive system. It also plays a role in urine flow and helps in hormone production. Roughly the size of an unshelled walnut, the prostate sits in front of the rectum, just below the bladder. A healthy prostate is smooth and symmetrical, with a springy surface. Due to its location, it cannot be felt from outside the body.

During a DRE, the doctor feels the gland for possible anomalies. This includes areas that are hard or lumpy, the presence of nodules, areas of tenderness and evidence of enlargement. The procedure typically lasts less than a minute and, while it can cause discomfort, it should not be painful.

Due to the positioning of the prostate, a digital rectal examination only allows access to the back wall of the gland. Any abnormalities that are present in the central or forward portions of the organ cannot be felt via this method. For that reason, a blood test, called a PSA test, is also used as part of prostate screening.

PSA is short for prostate-specific antigen. That’s a type of protein that is produced by several types of tissues in the human body, including by the prostate gland. Elevated PSA levels can indicate the presence of cancer. However, advancing age, inflammation, infection and an enlarged prostate can also result in higher PSA readings. So can recent ejaculation and certain medications. For this reason, elevated PSA levels are not considered to be an automatic indicator of prostate cancer. Rather, they signal the need for further investigation to determine the potential causes for the reading.

Although a PSA test can flag the presence of cancer that may not be discovered in a digital rectal exam, the opposite is also true. Some types of prostate cancer don’t cause a rise in PSA, and if they are located at the back of the gland, may be detected during a DRE. That has led some doctors to always use both types of screening.

It’s disappointing your new doctor failed to fully explain her position regarding the use of DRE. It left you feeling dismissed, which damages the patient-doctor relationship. However, we don’t think she was acting on her personal preferences, but rather on her understanding of the latest screening guidelines. We urge you to broach the subject with her again. Keeping in mind important factors such as your age, general health, medical history and family history of cancer, the two of you can find the best prostate cancer screening for your specific situation.

(Send your questions to [email protected], or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)