The rule used to be that the pre-negligence survival had to be more likely than not. In other words, over 50% below that level, any harm that the plaintiff suffered was attributed to their disease, even if the doctor was held to have been negligent. What this came down to, though, was that negligent physicians who happened to have been negligent on people with worse illness were protected. Courts began to separate causation from damages. This changed the analysis from the preponderance of the evidence, the greater than 50% standard that we use to determine if there’s negligence in the first place, to one of pure damages. The loss of chance for a better outcome
or a cure is now gradable on its own value. Just as, for example, the loss of a chance to make a living is due to the malpractice. When there is a treatment failure after a negligent act, it’s likely that jurors, who have faith in modern medicine and who believe that early detection leads to cure, will conclude that the harm must have occurred solely because of the negligence. So actual limitations in the given case such as the inherent aggressiveness of the disease
or the patient’s own physical limitations should, therefore, be made clear to the jury.