QUESTION: Let’s clear the air once and for all Dr.P! What’s the deal with pregnancy tests detecting testicular cancer? – Mr.Ballsy
ANSWER: Testicular cancer is one of the rare cancers that can secrete “tumor markers,” or molecules that can be detected in the blood. The three common tumor markers for testicular cancer are AFP (alpha-fetoprotein), HCG (human chorionic gonadotropin) and LDH (lactate dehydrogenase). You can learn more about each of these tumor markers at: http://urology.jhu.edu/testis/testis_cancer_markers.php.
A recent story on the internet highlighted the story of a young man who was “diagnosed” with testicular cancer by using an over-the-counter pregnancy test. While I don’t know this patient, I’m sure his story is true – I’ve had a few patients in my practice who had a “positive” pregnancy test before coming to see me. However, this young man, Byron Geldard, had doctors in Cambridgeshire, Engand, puzzled when he presented with pain in his side and an uncertain malignancy that had spread around the body.
(This story was reported in The Telegraph, March 9, 2015: Teenager Diagnosed With Testicular Cancer After Pregnancy Test). The doctors in Great Britain used a pregnancy test to confirm the diagnosis of testicular cancer in Byron – creating a sensational news story.
While it worked in this circumstance, an over-the-counter pregnancy test is not a great test to diagnose testicular cancer. Knowing that testicular cancer would be the most common malignancy in an 18 year-old man and ordering simple blood tests could have also confirmed the diagnosis of testicular cancer in Byron. Since this story has been plastered around the internet and social media, here’s the truth about HCG, pregnancy tests and testicular cancer…
Pregnancy tests work by detecting HCG in the urine – the same protein that can be secreted by some testicular tumors. So, if you have a testicular tumor and it secretes HCG, a home pregnancy test may confirm that diagnosis. However, HCG is only rarely secreted by testicular tumors:
• Only 15% of early-stage seminomas and 20-40% of NSGCT (non-seminomatous germ cell tumors) will secrete HCG.
• Even in cases of advanced (metastatic spread to lymph nodes or other sites) testicular cancer, only about 50% of tumors (seminomas or NSGCT) will secrete HCG.
In addition, HCG levels need to be relatively high to be detected by the over-the-counter urine tests. Some urine pregnancy tests will detect HCG levels of 20 mIU/mL, but most rely on levels >100 mIU/mL. Of the minority of testicular cancer patients whose tumors secrete HCG, many patients will have HCG levels beneath the detecting capability of a home pregnancy test.
Therefore, HCG (and pregnancy tests) are an unreliable screening test for testicular cancer. If you feel an abnormality during testicular self-exam the first thing you NEED TO DO is contact a physician and make an appointment. If the doctor is concerned, an ultrasound (painless) and blood tests (mostly painless) are the next correct steps. If you’re curious while you wait, try a pregnancy test. If it’s positive then you know the diagnosis and find the nearest testicular cancer expert. If the pregnancy test is “negative” that does NOT necessarily mean that you do NOT have testicular cancer. Remember, upwards of 80% of testicular cancers will NOT secrete HCG so do not rely on a home pregnancy test to prove you are cancer free!