I don’t know why Mr. Moto feels the angles are all wrong. The physicial part would actually be quite easy. You wouldn’t reach from behind (as many people use toilet paper); reaching between your legs, in a sitting position would give an ideal alignment that is at least as convenient, if not more, than my hand position when I examine a patient’s prostate from behind.
He is quite right that a layman is unlikely to know what changes are significance, but frankly, that’s not brain surgery (fill in your own joke). The patient will know the feel of their own prostate better than I would, and might be able to detect a change sooner, if only because they can conveniently check more often.
The biggest problem would be memory. After a few dozen prostates, a doctor gets a good idea of the various forms of normal, and can describe the rubberiness and internal texture accurately in a few words that will draw a clear picture in their mind a year later when they re-read their notes for the next exam. A layman might forget exactly what it felt like last time, especially if they do it infrequently, but I suspect that after a dozen or so conscientious self-exams, they could develop a pretty good memory of what their normal felt like.
IF your doctor teaches s/he may have a rubber model that replicates the texture of various important findings. If not, s/he can usually get one from a drug rep.
The things you look for are not hard to detect. The substance of a normal prostate is uniform and feels a lot like the eraser on the end of a pencil. With increasing age it tends to get a bit firmer, but not really hard. Sometimes the duct can be felt. If you know your own prostate well, it wouldn’t be difficult to learn to detect new fluctuent areas of liquid, firmer masses or grainy hard particles within this fairly uniform body, especially if they are fairly near the surface. You might even have an advantage in self-exam due to internal sensation: you would know exactly the sensation in your prostate feels when you palpate it, and might notice tenderness or other changes earlier and more reliably than you’d notice the less familiar sensations of having your prostate palpated every year or more, perhaps by different doctors.
It would be important to check all parts of the prostate, all the way out to the outer edges (which might not be obvious to a layman), a sloppy exam could lead to false reassurance. It’s also important to be completely honest with yourself, and make sure to follow up any unusual findings promptly with a physician.
I wouldn’t rely on my off-the-cuff description above (I’m already thinking of ways I could improve it.) However, I do believe that it would be possible to construct a useful prostate self-exam training program for laymen. In fact, I’m halfway considering doing it. Of course, there would have to be many studies to validate its benefits, if any. Maybe I’ll search the literature later today.
I would absolutely not advise replacing a physician exam with self exam. In fact, I am not advising anything in this post. It is strictly for information purposes. I do believe, however, that regular careful prostate self-exam (don’t injure yourself!) might be a helpful adjunct, if the patient were properly instructed.
Again: don’t skip the physician exam, and see a physician if you find anything unusual. Some significant findings can be subtle, especially deep within the tissue.