How does filing a lawsuit against physicians for medical malpractice cancer misdiagnosis work?

In order to prove his medical malpractice in cancer case, one must show that it was "more probable than not the negligent act was a cause-in-fact" of his injury.  Jennings v. Palomar, 8 Cal.Rptr.3d 363, 114 Cal.App.4th 1108, at 1118 (Cal. App., 2003)

"A possible cause only becomes 'probable' when, in the absence of other reasonable causal explanations, it becomes more likely than not that the injury was a result of its action.'"

Courts require that medical malpractice actions be proven "within a reasonable medical probability based on competent expert testimony, i.e., something more than a `50-50 possibility.'"  There must be sufficient evidence for the jury to find that absent the physician's negligence, there was a "reasonable medical probability" that injured person would have reaped a better result.  You can prove causation by presenting evidence that he suffered increased financial costs and greater physical discomfort due to the delayed diagnosis.