Thursday, 30 May 2013

Delay in Diagnosing Cancer (3) - Diagnosis and Staging

In Part 2 I considered the first links in the chain of causation - establishing when the claimant would have been seen by a specialist and what investigations would have been carried out, but for the negligent failure to refer. The next step is for the claimant to prove, on the balance of probabilities, that such investigations would have resulted in diagnosis of cancer.

In order to prove whether the investigations which would or should have been performed would have led to diagnosis it is necessary to establish what the likely features or characteristics of the cancer would have been at the relevant time. In rare cases there is direct contemporary evidence - a scan which was misinterpreted for example. Far more commonly the court will be invited to make a finding as to the presence and features of the cancer at the time when investigations were not, but ought to have been performed, by inference. Evidence from which inferences may be made will usually include reported symptoms over time and, most importantly, the features of the cancer when diagnosis was actually made.

An expert oncologist or histopathologist will take the evidence of the cancer at diagnosis - its size, its stage, its grade etc. and calculate or make a judgment as to the corresponding characteristics at the earlier time when investigations ought to have been performed - this is called interpolation. The expert will rely on evidence of how such cancers typically behave over time. For example there is evidence of "doubling times" for breast cancer - the period over which the tumour will double in volume. The doubling time will depend on the precise category of the cancer and the age of the patient.

Even with cancers such as breast cancers where there are published studies of doubling times, the experts will only be able to give a range of sizes for the tumour at an earlier time. Nevertheless they may be able to establish that on the balance of probabilities the tumour would or should have been detected on a triple assessment at a breast clinic.

There are greater difficulties with less common cancers, where there is a lack of data as to doubling times. Sometimes experts will rely on evidence of doubling times for similar cancers but this may be controversial. In McGlone-v-Greater Glasgow Health Board the claimant's expert had used published studies to interpolate the size of the claimant's cervical tumour at the time when it was alleged diagnosis ought to have been made. The Court of Session, Outer House, rejected that evidence. First, it found that it was inappropriate to rely on published evidence of doubling times for metastatic lung tumours as indicative of the likely doubling time for a primary cervical tumour. Second, it noted the very wide range of doubling times and rejected the notion that the court should simply take the mean doubling time within that range.

The decision in McGlone indicates that the use of statistical evidence without more can lead to difficulties in proving causation. Furthermore that where there is an absence of data directly relevant to interpolation in respect of the particular cancer, then the claimant may face further difficulties. Nevertheless the Court recognised that statistical evidence might be probative of a range of tumour size.

Of course evidence of the growth rates of tumours is difficult to obtain - clinicians do not generally leave a tumour to grow simply to observe how it behaves! If the courts were unwilling to rely on any statistical evidence or to make findings by inference then most claims for delay in diagnosing cancer would fail. This is an area where direct evidence of the features of the cancer at the time of the alleged negligence will, by definition, almost always be absent.

Sometimes the expert evidence will conclude that whilst the tumour would not have been present at the time when investigations ought to have been performed, pre-cancerous changes would have been present and detected - such as ductal carcinoma in situ in the breast. However merely establishing that the cancer or other abnormalities would have been present does not of itself prove that diagnosis would have been made. There seems to be a "rule of thumb", for example, that a breast tumour less than 1cm diameter might well be missed even on a reasonable clinical examination of the breast. Other investigations for other cancers are far from guaranteed to lead to diagnosis even if the cancer can be proved to have been present at the relevant time.

If diagnosis would or should have been made then by similar process, proof will be required of the characteristics of the cancer. Generally the relevant features are the size of any tumour, the stage and/or grade, and the spread of the cancer to neighbouring or distant sites. However associated symptoms may also be relevant to the categorisation of some cancers - for example night sweats. There are different categorisations for different cancers. So, melanomas may be measured for their Breslow thickness, colorectal cancers may be given a Dukes stage etc. For prostate cancer the stage is a measure of the extent of growth or invasion and the Gleason grade is a measure of the activity or aggressiveness of the cancer. Many cancers are categorised by reference to a TNM staging - T for tumour, N for nodes and M for Metastases. So a breast cancer may be T1N0M0 meaning that there were no axillary nodes affected and no metastases. I find the Cancer Research UK website very useful for information about grading and staging. 

So proof that diagnosis would have been made on earlier referral depends on a combination of evidence of the characteristics of the cancer at the relevant time and the investigations which would or should have been performed. Would those investigations have resulted in diagnosis of that cancer? The characteristics of the cancer at such time are relevant both to the likelihood of diagnosis being made and to the treatment of the cancer at that time and the patient's likely prognosis.

In the further posts I will look at treatment, prognosis and life expectancy and bringing claims for claimants with reduced life expectancy. I have posted links to resources and authorities here.





Friday, 24 May 2013

Delay in Diagnosing Cancer

Claims for Delay in Diagnosing Cancer - A Series of Six Blog Posts














Part 1 - Breach of Duty
Part 2 - Investigations on Referral
Part 3 - Diagnosis and Staging
Part 4 - Treatment
Part 5 - Reduced Life Expectancy
Part 6 - The Dying Claimant 

Here are links to various publications, websites and authorities which may be of use to those who have read my posts on litigation arising out of delay in diagnosing cancer.



Resources

Referral Guidelines for Suspected Cancer - NICE 2005

Improving Outcomes in Breast Cancer - NICE

PREDICT - a model for clinicians and patients to help decide on treatment and which will assist with prognosis

NPI - the Nottingham Prognostic Index - online tool but use with care - no substitute for expert advice

Adjuvant Online - requires registration to use and should only be used by clinicians - but added here for information

Cancer Research UK - a very helpful resource for information about cancer

Breast Cancer Care - a helpful resource for information about breast cancer

Factor 50 - helpful resource for information about skin cancer

AVMA - Action against Medical Accidents - organisation helping those who have suffered as a result of medical accidents.

Patient.co.uk - website with health information including on cancer



Authorities

Gregg-v-Scott [2005] UKHL 5

JD-v-Mather [2012] EWHC 3063 (QB)

Oliver-v-Williams [2013] EWHC 600 (QB) 

Adhsead-v-Tottle - Unreported 25/20/07 Gray J

MOJ-v-Carter [2010] EWCA (Civ) 694


Manning-v-Kings College Hospital [2008] EWHC 1838 (QB)

Thompson-v-Arnold [2007] EWHC 1876 (QB)

McGlone-v-Greater Glasgow Health Board

Crowther-v-Jones - Lawtel report of out of court settlement (approved)


Wednesday, 22 May 2013

Delay in Diagnosing Cancer (2) - Investigations on Referral

As all litigators know, in negligence claims the claimant has to prove both negligence and causation. In delay in diagnosing cancer claims, establishing that a GP or other primary healthcare provider has been negligent may be the easy part. Proving causation is often the most difficult element of the claim.


The first link in the chain of causation, is to establish when the patient would have been seen, on referral, and by whom. The NICE guidelines are again helpful (see Part One) since they set out timelines for referral. It is usually obvious which kind of clinic or specialist would have seen the patient on referral, but in some cases the GP expert will need to advise to whom the referral would or should have been made.

The second link is what would have been done on referral. What examinations or investigations would have been performed? It is that issue that I shall address in this post. In future posts I shall look at the next links in the chain: what would have been found on investigation or examination, what treatment would have been offered and chosen, what would the results of treatment have been, what additional injuries have been suffered as a result of the delay and what effect has the delay had on life expectancy?

In relation to some suspected cancers the question of what would have been done on referral is not difficult. For example where there is a suspected melanoma, it is likely that on referral to the pigmented skin lesion clinic, the lesion will be excised and sent for histopathological examination. The NICE guidelines caution against GPs removing such lesions. In other cases, such as with suspected breast cancer, the answer is more complex.


NICE (again) provides guidance on the assessment which ought to be carried out for suspected breast cancer in its (updated) publication "Improving Outcomes in Breast Cancer". NICE advises that:

"The same standard of care should be provided for all patients with suspected breast cancer, whether they are identified by screening or referred with symptoms. The combination of clinical examination, mammography/ultrasound and image-guided core biopsy or fine needle aspiration (FNA)  - known together as triple assessment - should be available for women with suspected breast cancer at a single visit. Both mammography and ultrasound imaging should be available. Centres which predominantly use core biopsy should also maintain expertise in FNA cytology so that this method can be used when appropriate."

Thus the triple assessment would or should be followed on referral for suspected breast cancer. It does not necessarily involve all three stages being performed. A claimant will need to establish that a triple assessment would have led to diagnosis, but if clinical examination would have been normal  then, in the absence of other good reason to proceed to radiological examination there may have been no ultrasound examination or mammography or biopsy. In one case I conducted much turned not on whether radiological investigation should have been performed but which form it would have taken -ultrasound or mammography. One would have probably led to diagnosis the other not.


You might think it very unlikely that clinical examination of a breast would be normal when it is likely that the GP has referred the patient because of a finding of a lump. However, sometimes referral is because the patient themselves can feel a lump, whereas it is not detectable on reasonable clinical examination. Alternatively the detectable lump may be benign but there is another lump which would have been malignant at the relevant time but not clinically detectable .

Other investigations for other suspected cancers may involve endoscopic investigations such as a cystoscopy or sigmoidoscopy, x-ray or scanning.

It is also worth considering what advice would or should have been given on referral, assuming that the investigations did not lead to diagnosis on the first referral. For example advice which ought to be given might be to monitor symptoms, to return to the GP in the event of certain problems, or to be reviewed by the specialist in 3 or 6 months. In some cases a return to the specialist team after persistent or worsening symptoms may then have led to further investigations and to diagnosis. So, the GP's referral in March might have led to diagnosis in September rather than in April.

Next time ..... Diagnosis and Staging