Interesting thread. I'm researching this "talc on trial" question for a (premed) cancer biology course. I first looked into how a substance gets labeled a carcinogen. The IARC (Int'l Agency for Research on Cancer, iarc.fr) labels talc a possible carcinogen in certain contexts (i.e., using talcum powder for so-called feminine hygiene). In the US, the NTP (National Toxicology Program,
https://ntp.niehs.nih.gov) keeps a list with only two categories: known carcinogens and probable carcinogens. Talc is not on either of those lists. Then I switched gears to look at the complaint in one of the recent talc cases in which the plaintiff got a large award from the jury. Keeping in mind that I have not read the answer yet, the complaint makes several troubling assertions, including that Johnson & Johnson formed a trade association in response to the growing complaints, and that trade association edited some of the scientific research presented to the NTP when it was determining whether to list talc as a carcinogen or not. Again, I have not read the answer yet, so I can't say on how Johnson & Johnson responded to this, although jury members have been quoted as saying that the plaintiff's evidence was pretty damning, and in fact they awarded around twice what the plaintiff had asked for in punitive damages. I then turned back the workings of the NTP - when founded in 1980 or so, they had a council of 35 scientists and a budget of about $200M+, and were investigating 240+ possible carcinogens. Fast forward to today: they are looking at 4 possible carcinogens, 23 of their council seats are empty, and their annual budget is $26,000. One of the 12 filled seats is held by a senior employee of Johnson & Johnson.
There aren't good cohort studies, it's true, but the one that exists found a 33% increased risk of ovarian cancer. Also, doctors have found talc inside of ovarian tumors. Seems to me enough to warrant more research. My own view is that even if talc doesn't cause ovarian cancer, Johnson & Johnson should be held accountable for trying to screw with the process, if they indeed did so.
I sat on a jury once for an asbestos/mesothelioma trial. I thought the plaintiff's lawyer in that particular case, with that particular set of facts, was only there to throw spaghetti at the wall to see what would stick. He admitted in his opening statement that he had no direct evidence that the plaintiff had ever come into contact with the defendant's product, and his firm was a known "asbestos mill." In that case, he didn't get much from our jury. On the other hand, forty years ago, every defendant in every one of these kinds of cases claimed that breathing asbestos was perfectly safe. We know now that it is not.
Is talc the new asbestos? Probably not, but I'd like to see more studies and stronger funding for the NTP (on the connection between talc and ovarian cancer; hopefully we can all agree that no one should be breathing it in). I can also post here again when I've done more research, including reading more of the legal pleadings. But the notion that all plaintiff's lawyers are scum, therefore talc can't possibly cause cancer - come on. You have to respect the evidence, even if it's delivered by someone in a bad polyester suit.