sure, in your science class, ca might refer to calcium or california in geography or something else in some other class but if you hear your doctors talk about ca, they're talking about cancer. sometimes we use it when we don't want to alarm patients, families or others who may be in earshot, particularly when we don't really suspect it but do need to consider it in the possibilities of what might be wrong with someone. obviously, if your doctor has a fairly low suspicion of cancer but are doing a couple of tests to "rule it out" then you don't necessarily want to worry about it for days while the tests are pending. all you want to hear is, "oh yeah, whatever you have, it's not cancer." well, not to be paternalistic, but at least to me, i certainly wouldn't want to be worrying about it.
a couple of questions came up about prior ca topics. as for screening, colon cancer seems to be more straightforward but it's certainly not the case for breast cancer. unfortunately, no matter what type of cancer, there are always particularly aggressive forms in some people that defy all screening. we see patients with no family history of cancer who come in with colon cancer diagnosed in the 20's and 30's, breast cancer in the same range too. screening would not have helped and these patients aren't usually the ones who live a long life. these are usually advanced diseases we see in the hospital. those are the unfortunate outliers. screening programs are basically a numbers game--how prevalent is the disease in a certain group, how good are the tests, how much will all of it cost, etc. if you have a strong family history of breast cancer, as far as i know of, there are no clear-cut guidelines on early screening. of course, most recommend an early baseline mammo then yearly (or every other year) starting at age 40. but what if you're 20, 25 years old? there are genetic testing options for the brca gene but that probably shouldn't be done without counseling from a medical geneticist because the answers aren't as straightforward as you might think.
a friend also commented on gene upshaw, the former nfl'er, players union director who died somewhat suddenly of pancreatic cancer. again, some cancers in some people can be particularly aggressive. he was apparently sick at least for a little while (but not too long) but didn't get seen by a doctor. some cancers don't manifest themselves until it's almost too late. that's part of the reason the mortality for ovarian cancer and pancreatic cancer are so high. i just read another nice q&a session on the scientific american website here. more good info regarding cancers, particularly pancreatic. i'll talk about prostate cancer screening later, another very controversial area.