Further to an earlier post, the New South Wales Court of Appeal has recently delivered its decision concerning the appeal in relation to Ms O’Gorman’s delay in diagnosis of breast cancer claim.

Tragically in the period between the initial decision in her favour and this appeal, Ms O’Gorman died from her metastatic breast cancer.   As a consequence the appeal was contested by her Estate.
The Area Health Service responsible for BreastScreen New South Wales, the Sydney South-West Area Health Service succeeded in its appeal and the Court of Appeal have ordered a re-trial on the issue of negligence.

The primary reason for the Appeal being upheld and a re-trial being ordered was the Court of Appeal’s view that the trial judge had been wrong to refuse to allow the two radiologists involved in assessing Ms O’Gorman’s original breast images to give evidence as to whether they had taken reasonable care in examining her breast images.

This is a not uncommon situation. A defendant seeks to bolster its case by reinforcing its “independent” expert witnesses’ opinions by the views of the particular doctors concerned. I have had first hand experience of this in several cases at and approaching trial in the last two or three years.

Consistent with the New South Wales Court of Appeal’s decision, the generally accepted position is that such evidence cannot be put forward unless its substance has been disclosed an appropriate period prior to trial (as with any other expert’s opinion).  By this means the parties are given an appropriate opportunity to consider such opinion, its foundation and prepare cross examination etc.

Subject to this requirement, such expert evidence can generally be put forward, albeit (and this point was acknowledged by the New South Wales Court of Appeal), there will always be issues as to the weight to be attached to such opinion given the witnesses’ lack of impartiality.

More interestingly in a general sense, the Court of Appeal in this case made some interesting observations in relation to causation questions.

The lead decision was provided by Ipp JA. Justice Ipp reiterated that in New South Wales at least, showing that negligent medical care has increased a risk of injury and such injury has occurred, is not enough to show that such injury occurred because of negligence.

The position in New South Wales at least, following Seltsam v McGuiness [2000] NSWCA 29 is that the Court must still be satisfied on a balance of probabilities that the risk of injury created by the lack of care is indeed the cause and the injury has happened because of the negligence medical care.

Perhaps I am missing something, but this does not explain to me how the facts in Ms O’Gorman’s case satisfied this test. Hopefully someone reading this can enlighten me!

As indicated in my earlier post, the findings by the trial judge (accepted on appeal) where that because of the delay in diagnosis and treatment of Ms O’Gorman’s cancer, her chances of metastases occurring had increased by 10% (though from what % is not clear to me).

Because this had occurred by the time of trial, I would have thought it could be looked at as a case in which Ms O’Gorman had lost, because of the alleged negligence, the 10% (or other figure, depending on her overall risk of this) chance that such metastasis would not have occurred. This was actually how the defendant tried to argue the case at trial, though by appeal time Gett v Tabbet [2009] NSWCA 76 had been decided and so any assessment of the loss as “a chance” would have had disastrous consequences for Ms O’Gorman’s claim (her estate).

It could be said that the strong likelihood on such evidence was that the negligence had not caused her metastases and death. Certainly on a scientific balance of probabilities, it appears it was > 50% probability that such metastases and death would have occurred in any case.

The trial judge’s finding was that rather than a lost chance, what BreastScreen’s negligence had caused was the metastasis itself (ie in effect, somehow she was in the % who otherwise would not have developed such spread). This was accepted as the right approach by Justice Ipp and other members of the Court.

Although I confess I have difficulty in understanding the Court’s reasons (no doubt, due to limitations on my part), my impression is that there is a “likelihood threshold” at play.  In other words, where the increase in risk of a particular injury by negligent care is very small (or uncertain), the “jump” to accept that when such form of injury has occurred, this is because of the negligence, will not be made.

Put another way, though I hasten to add the Court did not say this (!), for an increase in risk to be found to have caused injury, the increase in risk may need to be more than just material. This seemed Ipp JA’s explanation (not in so many words) why Gett v Tabbet did not exclude success here. At [131] Ipp JA suggested that Gett’s case failed because the patient had been unable to establish "there would, as distinct from may have been a better medical outcome." If this is the test, I would have thought Ms O’Gorman should have failed as well.

Ipp JA suggested (I think unfairly) that the evidence in Gett as to the prospects for the patient with better care being improved was “at most, speculative” [132].

Ipp JA’s decision goes on to make interesting reading in terms of the difference between “probabilities” in maths or science and on the other hand, in Law. He refers to statements in Jones v Sutherland Shire Council [1979] 2 NSWLR 206 as to the meaning of the critical legal phrase “a balance of probabilities”. This emphasises an impressionistic, subjective concept. The quote reads:

“The first step, in a sense, simply involves an assessment of what is human experience: it is, or is not, a fact that human experience is so. But such an assessment is not made as a mathematical calculation. It involves other kinds of reasoning and judgements, the correctness of which cannot be demonstrated by mathematics or ordinary logic. Therefore, the subjective confidence which a person or a Court will have in the correctness of the assessment may vary.”

As can be seen therefore, it is absolutely wrong, though very common (in this jurisdiction at least!), to suggest in a medical negligence case that whether proven negligence can be shown to have caused damage is a matter decided by the expert evidence and expert opinions, as to whether as a matter of science, this is likely.

It is true that expert evidence will inform the Judge concerning the scientific issues relevant to a mathematical assessment of the probability of a link between negligent care and the outcome.

As Justice Ipp and the Court of Appeal’s decision however illustrates, this is only a first step in the process. The Judge’s “valued” judgement as to whether in law a link should be accepted must then be performed and may quite legitimately reach a contrary conclusion to science (as perhaps in Ms O’Gorman’s case).

Ipp JA relies upon this meaning of “a balance of probabilities” in concluding that the scientifically evident “strong possibility” (which as stated, was in fact 10% or so) that had the radiologist detected the tumour it would not have metastasised, would not require a “great deal of evidence… to tip the scales from the strong possibility to a finding that, on a balance of probabilities, the failure to detect the tumour lead to metastases” [148].

Obviously these issues of the role of science in proving causation in complex litigation and what should happen where science is unable to explain or assist a Court as to a potential link between potentially negligent acts and adverse outcomes (so called “evidentiary gap” cases) is something the High Court is likely to clarify when Amaca and Ellis are delivered.  Watch this space!