Prostate Cancer and Low Testosterone
Concerned that testosterone (TST) replacement therapy might accelerate growth of occult prostate carcinoma in hypogonadal men, the authors included prostate biopsy, directed by transrectal ultrasound (TRUS), with their standard screening of digital rectal examination and serum prostate-specific antigen (PSA) prior to initiating treatment in men intended for TST therapy. It was hypothesized that hypogonadism might produce false-negative PSA testing, and change the nature of a prostate mass lesion rendering it undetectable by digital rectal exam.
Seventy-seven hypogonadal men who had been referred for sexual dysfunction underwent screening, which detected 11 cancers (14%). PSA levels, the highest of which was 2.9 ng/mL, did not discriminate between patients with or without cancer. The ratio of total TST to free TST was significantly higher in the cancer group.
Prostate cancer generally produces more PSA on a gram-for-gram basis than normal prostate tissue, resulting in a higher PSA and PSA density in men with cancer. Previous trials have shown that TST supplementation in hypogonadal men elevates PSA. The authors suggest, based upon their study, that PSA expression may be a TST-mediated event, and, hence, if TST or free TST are reduced, signal elevations of PSA may be absent. Inclusion of a free and total TST merits consideration in a comprehensive screening for prostate cancer.
Morgentaler A, et al. JAMA 1996; 276:1904-1906.
Clinical Scenario: The ECG shown in the figure was obtained from an asymptomatic 77-year-old man. What abnormalities are present on this tracing? What is the likely significance (if any) of these findings?
Interpretation: The ECG shows sinus arrhythmia. The mean QRS axis is about -40°, and QRS morphology is consistent with left anterior hemiblock (LAHB). There is an rSr' pattern in lead V1. Transition occurs somewhat early (between leads V1-V2) in the precordial leads. Narrow q waves are present in leads V2 to V6. However, there is no evidence of any acute ST-T wave changes.
Clinically, the presence of sinus arrhythmia, LAHB, and an rSr' pattern in lead V1 are each unlikely to be significant as isolated findings. The presence of narrow q waves in the anterior (and/or anterolateral) precordial leads is an additional finding that is quite subtle, but not unusual in older individuals. Because the q waves in leads V2 to V4 are small (as they most often are), they are easily overlooked. Determination of their clinical significance is equally problematic. Three causes have been attributed to this finding:
1. Anterior infarction
2. Rotation of the thoracic aorta
3. Pseudoinfarction pattern produced by LAHB.
In elderly patients with atherosclerosis, the aorta often becomes tortuous. When it "uncoils," the ascending aorta may rotate to the right in such a manner as to pull the left ventricular outflow tract into a more anterior position. Concomitant rotation of the interventricular septum results in production of a qR complex in the anterior precordial leads.
It is important to appreciate that LAHB may mimic or mask the diagnosis of myocardial infarction in a number of ways. Inferior infarction may be difficult to recognize because LAHB may prevent inscription of diagnostic Q waves in the inferior leads. The presence of LAHB may also mimic anterior infarction. Although primarily a superior and lateral structure, the left anterior hemidivision of the left bundle branch lies relatively more anterior than the left posterior hemidivision. Consequently, after the impulse leaves the bundle of His, it will be oriented in a relatively posterior direction if the more anterior hemidivision is blocked (as it is in LAHB). This may produce small q waves in the anterior precordial leads.
The point to emphasize is that one cannot rule out previous anterior infarction from simple inspection of an ECG (such as the one in the figure) that demonstrates early transition with narrow q waves in the anterior precordial leads. Nevertheless, among asymptomatic elderly individuals, rotation of the thoracic aorta and/or LAHB are much more common causes of this ECG pattern.