prostate-glossary

Deliberately giving large doses of testosterone to men whose prostate cancer has learned to live without it, swinging the level from very high to very low each month. It is the opposite of standard treatment, and about a third of men respond, with about half then responding again to the hormone-blocking drug that had stopped working.

Instead of collecting damage one mutation at a time, a prostate cancer genome can be scrambled in a single burst: several chromosomes break at once and are stitched back together in a chain, knocking out several cancer genes in one event. It was discovered in prostate cancer and named there.

A score for how much of a tumour's genome has lost one of its two parental copies. A high score is a scar left behind by a broken DNA repair system, and is used as a rough sign that a PARP inhibitor might work. It is a measure of damage already done, not of the fault that caused it.

Taking planned breaks from hormone therapy once the PSA has settled, restarting when it rises again. The aim is to give a man time back with his energy, his libido and his mood. The largest trial found the benefit was real but lasted about three months, and could not rule out a worse chance of survival.

Finding a cancer earlier means you know about it for longer, even if nothing you do changes the day you die. That extra stretch of knowing is called the lead time, and lead-time bias is the mistake of counting it as extra life. It is the single biggest reason survival figures make screening look better than it is.

The time from joining a trial until a scan first shows the cancer has spread, or the man dies, whichever comes first. It is the endpoint that got three hormone drugs licensed for prostate cancer that had not yet spread, because waiting for deaths would have taken another decade.

Prostate cancer cells that have taken on the look and the markers of nerve-and-hormone cells. A trace of it is present in almost every prostate cancer and means nothing; a tumour made mostly of it is a different and much more serious disease, and it usually appears after years of hormone treatment.

How many men have to be offered the test for one man to be saved from dying of prostate cancer, and how many extra cancers have to be found along the way. In the big European trial the answer at sixteen years was 570 men invited and 18 extra cancers diagnosed per death prevented, and the figures get better the longer the trial runs.

Dying of something that is not the cancer. In prostate cancer most men do, which makes it the outcome that decides how much any treatment can possibly help. It is also where the inequality that survives equal cancer care shows up, and almost no cancer service measures it.

Treating a cancer that was never going to cause trouble. It is the harm that overdiagnosis causes: the diagnosis itself does not leak urine or end erections, the operation does. Published estimates of how much prostate cancer is overdiagnosed range from under 2 percent to two thirds, and the range is a fact about the methods, not about the disease.

The international scoring system radiologists use to say how likely a prostate MRI finding is to be a serious cancer, from 1 (very unlikely) to 5 (very likely). British NHS reports usually do not use it: NICE asks for a 5-point Likert score instead, and the two look identical on the page and are not the same thing.

A single number adding up hundreds of common, individually tiny genetic differences to say whether a man's inherited risk of prostate cancer is above or below average. It is not a test for a faulty gene like BRCA2, and it says nothing about how aggressive a cancer would be.

In cancer that has already spread, this is the time until the scans show it getting worse, or the man dies. It deliberately ignores a rising PSA on its own, because in prostate cancer the PSA can rise for reasons that do not mean the treatment has stopped working.

A thorough biopsy done under general anaesthetic through the skin behind the scrotum, using a grid to sample the whole prostate systematically. It gives the most complete picture available short of removing the gland, and for that reason it is used as the yardstick in research rather than as a routine test.

Slicing the whole removed prostate into complete cross-sections on oversized slides, so each slide shows the entire gland in one piece rather than in fragments. It is the reference standard used to check how well a scan found what was really there.