Okay. Self Breast Exam or SBE used to be recommended. But studies have shown that they merely increase women’s anxiety and do not increase the number of cases and cures of breast cancer. Does that mean that if you feel a hard lump that you ignore it? Of course not. It just means that doing routine breast exams incur no benefit.
For mammograms, the answer lies in Bayesian statistics. The prevelance and incidence of breast cancer in a general population is low under age 40, and when you run the numbers you find out that a positive test is more likely to be a false positive than a true positive leading to higher unnecessary operations. The incidence and prevelance starts going up at 50, so that’s why that number is picked. Your results may vary. If you have, say, two sisters and a monther and an aunt who all had breast cancer when they were 25, then yes, of course you will get a mammogram early. But if you’re a general population then the risks outweigh the benefits.
What is Bayesian statistic you say? If you take a cohort of 1000 nuns who have never had sex nor shot drugs and tested them for HIV, and one of them come out positive, what is the chance that the test is a true positive? Because the incidence and prevalence (prior probability) is so astronomically low, there is a chance that the test is a false positive (happened to a friend of mind)
Now, lets take the same test and run it on 1000 sexually active gay sex workers who shoot heroin and share needles and don’t use any condoms. The incidence and prevelance is going to be much higher and so the prior probability is going to be much higher. Therefore the test is much more likely to be a true positive.
This doesn’t just happen for women. For prostate cancer there is a test known as a PSA that detects early prostate cancer. Good, right? Well, no, unless you are higher risk. Even if the PSA is positive, the chance that you’ll die of the cancer is less than the chance you’ll die of something else, and you are left with unnecessary procedures with side effects like impotence. Most physician men my age (52) do not take the test. A positive test causes morbidity, but not any mortality benefit.
But I’m an individual person, you say. I’m not a statistic. True. So you are free to do self breast exams—just make sure they are done correctly. You are also free to ask for a mammogram at age 40 (my wife did after hearing my rant on why she shouldn’t and did anyway. It was normal, thank goodness). It all depends on comfort and trust. But if you do it, ask yourself, are you willing to put yourself through a potentially painful surgery for something the statistics say has a greater chance of being benign than malignant?
But down to the meat of your question—what is a specific lump? You’re feeling around for something that feels like a walnut.
Hope that helps.