A testicular tumor almost always shows up as one thing: a small, firm, painless lump on the smooth body of the testicle, the presenting sign in about 95% of cases ¹. These tumors can double in weeks, so a lesion you couldn't quite feel last month can be obvious the next ¹.

This is awareness, not screening. The Cochrane review looked for any study comparing self-exam against no exam and found zero ². Men who present with advanced disease report a longer wait, three to six months between noticing and acting ³, but nobody has shown the habit itself changes the stage the cancer turns up at ⁴. Lifetime odds are roughly 1 in 250, so most men get nothing measurable from it ⁵. The value is narrow: you can only spot a change against a baseline you know.

Do it after a warm shower, when the skin is loose.

Monthly is the textbook cadence, but every shower to every few months does the job. The lever is the noticing, not the calendar.

Early versus late is one bad week against most of a year. Caught while it's still inside the testicle: one outpatient surgery, then imaging and blood draws for a few years ¹. Most men at this stage never need chemotherapy, and five-year survival sits near 99% ⁵. Found late, it drops to about 73%, and the treatment is months of cisplatin chemotherapy ⁵. The chemo works, but it leaves late effects for decades: higher rates of heart disease, secondary cancers, hearing loss, nerve pain, and reduced fertility ⁶.

Some men should pay closer attention. Incidence peaks from the early 20s to mid-30s, so the young reader carries the most exposure ⁵. Higher lifetime risk runs with an undescended testicle in childhood, even after surgical correction, a father or brother with the disease, or a prior tumor in the other testicle ⁷. In those groups, self-exam plus an annual clinician check is worth doing.