Undetectable Prostate-Specific Antigen in the Absence of Previous Prostatectomy: Laboratory Error or True Finding?

Abstract

Patient: A 51-year-old Caucasian male followed by the internal medicine clinic for many years because of multiple chronic medical conditions. Chief Complaint: Presented in November 2008 as part of a previously scheduled visit for routine follow up. History of Present Illness: Chronic longstanding hypothyroidism, type II diabetes, hypertension, obesity, dyslipidemia, trigeminal neuralgia, depression (with associated decreased energy and fatigue), and erectile dysfunction. Since the patient was now over 50 years of age, the battery of laboratory tests ordered included a prostate-specific antigen (PSA). Past Medical History: He had a motor vehicle accident in 1998 with traumatic brain injury and subsequent cerebrovascular accident following endovascular graft placement for aortic dissection. He has had chronic pain in his right leg since the accident for which he was medicated with oral hydromorphone as well as a morphine pump. Physical Examination: The patient was afebrile, with class II obesity (BMI=37.1), blood pressure of 133/62 mm Hg, and a pulse rate of 72/min. By rectal exam, a “very small” prostate with no other specific findings was encountered. The remainder of his physical exam was unremarkable. Family History: Noncontributory. Drug History: Noncontributory. Allergies: Penicillin, pentazocine, nalbuphine, butorphanol, clonidine, Lamotrigine, and nifedipine. Laboratory Findings: See Tables 1–3 . His primary care physician called the laboratory to inquire as to whether or not his screening PSA value was a laboratory error. 1. What are the current recommendations for prostate cancer screening? 2. What are the risk factors for prostate cancer? 3. What PSA value triggers evaluation for prostate cancer and what may interfere with the PSA assay? 4. What other serologic markers may help with prostate cancer detection? 5. What are the treatments for prostate cancer? 6. What are the reasons for a low PSA, and how would you evaluate the finding of an undetectable PSA? 7. How are his chronic complaints and …