Model essay. Critically evaluate screening for ovarian cancer.

Critically evaluate screening for ovarian cancer.

There is no proven method of screening for ovarian cancer.

Annual or twice yearly pelvic examination has been popular in the USA , but does not detect early disease.

Attempts were made to screen using abdominal ultrasound some decades ago.

They failed due to lack of sensitivity and specificity, the latter leading to many women having surgical procedures, some major, despite them having no serious disease.

Cervical cytology may show glandular cells and lead to a diagnosis of endometrial or ovarian cancer.

But this is very rare and could not be a basis for screening.

Any screening programme should fit as many as possible of the WHO criteria for screening.

The first is that the subject should be a significant health problem.

Ovarian cancer is the leading cause of death among the gynae cancers with 4447 deaths in 2005 and it ranks 4^th. in all cancer deaths in women after lung, breast and colon and affects about 1 woman in 50.

Despite heroic efforts to improve treatments, prognosis has not improved greatly in recent decades.

The WHO also states that screening should not be done until primary prevention measures have been implemented.

Apart from reducing the number of times a woman ovulates, there are no other known methods of reducing risk.

It has not been advocated that all women should take the combined oral contraceptive or other drugs for this purpose.

There are no specific warning symptoms of early disease that could be used in a health education programme.

An ideal screening programme should involve a disease with a natural history that is understood and a pre-malignant phase that is identifiable, the treatment of which is curative.

This is not the case with ovarian cancer.

Yet there is hope that early diagnosis could make a huge difference to morbidity and survival.

5-year survival for early stage 1 disease is nearly 90% while that of stage IV is little more than about 16%.

Most disease is currently diagnosed late and this is reflected in average 5-year survival rates of about 30%.

Earlier diagnosis could improve prognosis and morbidity by reducing exposure to chemotherapy.

Tumour markers, particularly Ca 125, have been evaluated.

They are useful in tracking disease response to therapy, but are not of proven value in screening.

The definition provided by ultrasound has improved hugely, particularly with the use of transvaginal scanning (TVS).

It is hoped that they could prove effective means of screening.

5 – 10 % of ovarian cancer is familial, mainly involving BRCA1 & 2.

A trial of screening, the UK Familial Ovarian Cancer Screening Study, UKFOCSS, has been set up.

It aims to see if screening with Ca 125 and TVS can identify disease at a treatable stage in this high-risk group:

    those with two or more close relatives with ovarian, breast or bowel cancer, particularly with early-onset disease.

Recruitment is planned to end in 2009, so it will be some time before any results are available.

A problem may be the tendency for women at high risk to have bilateral oophorectomy once their families are complete.

Despite the high risk of ovarian cancer for BRCA1 & 2 families, most ovarian cancer will occur in the low-risk population.

The UK Collaborative Trial of Ovarian Cancer Screening was set up in 2002 and has completed recruitment.

It is planned that it will run for ten years, but interim results may be helpful.

100,000 women will act as controls.

50,000 have been assigned to each of the active arms: one having an annual transvaginal scan, the other an annual assay of Ca 125.

There is an algorithm for the management of women with abnormal results.

A parallel study will look at the psychological consequences of screening.

Will it heighten or reduce anxiety?

And what of the women with an abnormal test in whom no disease is found?

These trials should help to answer whether such screening meets the other WHO criteria, such as cost-effectiveness and patient acceptability.

TVS is now widely used and appears acceptable to the vast majority.

The biggest worry might be anxiety generated by screening.

In the meantime, the only option for low-risk women is prophylactic oophorectomy.

But even that does not have a 100% guarantee: a tiny number will still develop an ovarian-cancer-like disease, perhaps originating in the peritoneum.

The 1 in 50 risk for most women is not enough to merit prophylactic removal of ovaries for low-risk women.

Though it becomes an issue for the woman having pelvic surgery, particularly hysterectomy, for other reasons.

As this is a common issue in clinics, junior doctors and clinic nurses should be trained to provide accurate information.

Good quality patient information leaflets would also be helpful.

The future may see better tumour markers, better genetic screening and improved ultrasound techniques making screening feasible.

Words 796. 18 minutes to plan and hand write.

You will not be expected to write so much in the exam.

I have tried to "cover all the bases" with this essay.

The exam committee gives a template with three or four sections.

This tells you the things you need to discuss and things in this essay that you can safely leave out.

Each section tells you the marks that have been allocated.

This tells you how much to write.

If you have any bright ideas for improvements, please let me know.

Tom McFarlane.