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Gynaecological Teaching Associates

February 16, 2016

Nice trial – pity about the ethics committee?

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Many trials comparing different teaching methods are of dubious quality (e.g. here), but this one (click here) in last week’s British Journal of Obstetrics and Gynaecology (BJOG) looked like it was going to be good – perhaps until the research ethics committee got involved.

Passing a vaginal speculum to take smears, fit coils etc., is a tricky skill to learn. Many medical schools let students practice on plastic models, which work reasonably well but are not very realistic. Others employ healthy women volunteers, who not only let students practice on them but teach, feed back on the student’s technique, and often become part of the teaching faculty.

Such gynaecological teaching associates (GTAs) are wonderful women, but do they really make for more skilful doctors? It would be good to have unbiased evidence. Unfortunately no firm conclusions could be drawn from the three poor quality randomised trials done to date. Hence the new trial.

It was prospectively registered here, with a planned sample size of 101 students (94 achieved) randomised in a 1.4: 1 (GTA: control) ratio, to maximise the use of available GTAs. The primary endpoint was the objective structured clinical exam (OSCE) score (range 0-54, high = good). The sample size was sufficient to show a shift in mean scores of about half a standard deviation. The OSCE was conducted with the student examining a model pelvis and scored by a GTA and a trained gynaecologist working together, neither of whom were aware of the student’s group. The result was negative. GTA training  made no difference. Median control group score 43, GTA group score 44, P=0.26. Oh dear!

But assessment on a plastic pelvis is surely not the best way to judge a student’s skill. Students trained on models may do fine in exams on models, but go to pieces when faced with the real thing, and only the person being examined can really judge if a doctor is being gentle. Why didn’t the researchers measure the student’s skill passing a speculum on a real woman, i.e ask a GTA to act as the exam model, as well as helping score student’s performance?

Perhaps they wanted to. There is a rumour that the researchers had planned to evaluate the students properly but were dissuaded by the research ethics committee, squeamish about something or other.

If true, this is outrageous – the trial may have given a false negative result, will need to be repeated, and more women will suffer avoidable discomfort and embarrassment – but it’s not easy to check. Queen Mary’s research ethics committee (click here) don’t publish their deliberations. Someone might speak up, but I’m not optimistic. No researcher wants to go on record about these sort of shenanigans; ethics committees have almost unlimited power to delay or meddle with projects.

Let’s hope I was misinformed.

Jim Thornton

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from → education, Health general, Questionable science, Trial Registry Troubles

The Beautiful Bowel Movement

January 19, 2016
tags: bowels, Dick Smiddy, John Updike, medicine, poetry, Surgery

By John Updike

In 1974, my first medical student “firm” at the General Infirmary at Leeds was led by two consultant general surgeons, Smiddy & Benson; Eddie Benson the taciturn straight man, and Geoff Smiddy the flamboyant Eric Morecambe character. One day, trailing round the old Nightingale wards, prodding abdomens and trying to differentiate inguinal from femoral hernia’s, we came to a poor fellow with ulcerative colitis. The teaching turned to defaecation.

“Young man,” boomed Smiddy. “Define a perfect stool.”

No adequate answer came.

“Twice round the pan and pointed at both ends. And don’t you forget it.”

I haven’t. It’s only when things go wrong that we fully appreciate the pleasure of a good shit. Updike knew it was worth a poem. Smiddy would have agreed.

Though most of them aren’t much to write about—
mere squibs and nubs, like half-smoked pale cigars,
the tint and stink recalling Tuesday’s meal,
the texture loose and soon dissolved—this one,
struck off in solitude one afternoon
(that prairie stretch before the late light fails)
with no distinct sensation, sweet or pained,
of special inspiration or release,
was yet a masterpiece: a flawless coil,
unbroken, in the bowl, as if a potter
who worked in this most frail, least grateful clay
had set himself to shape a topaz vase.
O spiral perfection, not seashell nor
stardust, how can I keep you? With this poem.

John Updike

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from → Health general, Poetry

Why the telephone wires dip and the poles are cracked and crooked

January 17, 2016
tags: grave, John Updike, Pennsylvania, poetry, son

By John Updike

In the introduction to his collected poems 1953-1993 Updike wrote:

“The very first poem here, bearing a comically long title, yet conveyed, with a compression unprecedented in my brief writing career, the mythogenetic truth of telephone wires and poles marching across a stretch of Pennsylvania farmland. I still remember the shudder, the triumphant sense of capture, with which I got those lines down, not long after my twenty-first birthday”.

In 2011 his son Michael carved the poem on the back of a memorial stone in Robeson church cemetery in Plowville, Pennsylvania, where some of Updike’s ashes are buried. According to the local paper (click here) the poet’s memory was faulty; he had composed it at age 16.

Whatever. It’s pretty good.

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The old men say
young men in gray
hung this thread across our plains
acres and acres ago.

But we the enlightened, know
in point of fact it’s what remains
of the flight of a marvellous crow
no one saw;
each pole a caw.

John Updike

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from → Poetry

My Children at the Dump

January 12, 2016
tags: adultery, children, Couples, divorce, John Updike, love, poetry

By John Updike

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In 1962 the Updikes had just moved to Ipswich Massachusetts, where John occasionally took his three older children to the local dump, leaving their new baby with his wife Mary. When his affair with Joyce Harrington was discovered, Mary confessed to one of her own, and forgave him. But Joyce’s husband wanted a showdown, so the family decamped to Europe to let the dust settle. The drama led to a whole series of stories about adultery, culminating in his first best-seller, Couples. 

This poem, – “Love it now./Love it now, but we can’t take it home.” – tells why Mary would win; he loved his children more than his mistress.

The day before divorce, I take my children
on this excursion;
they are enchanted by
a wonderland of discard where
each complicated star cries out
to be a momentary toy.

To me, too, the waste seems wonderful.
Sheer hills of television tubes, pale lakes
of excelsior, landslides
of perfectly carved carpentry-scraps,
sparkplugs like nuggets, cans iridescent
as peacock plumes, an entire lawnmower
all pluck at my instinct to conserve.

I cannot. These things
were considered and dismissed
for a reason. But my children
wander wondering among tummocks of junk
like stunted starvelings cruelly set free
at a heaped banquet of food too rich to eat.
I shout, “Don’t touch the broken glass!”

The distant metal delicately rusts.
The net effect is floral: a seaward wind
makes flags of cellophane and upright weeds.
The seagulls weep; my boys bring back
bent tractors, hoping what some other child
once played to death can be revived by them.

No. I say, “No.” I came to add
my fragments to this universe of loss,
purging my house, ridding a life
no longer shared of remnants.
My daughter brings a naked armless doll,
still hopeful in its dirty weathered eyes,
and I can only tell her, “Love it now.
Love it now, but we can’t take it home.”

John Updike

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from → Poetry, Sex

Ovarian cancer screening spin

December 22, 2015
tags: CA125, data driven analysis, ovarian cancer, randomised trial, screening, UKCTOCS, ultrasound

Breathless headlines

Telegraph: “Screening could prevent one in five ovarian cancer deaths, study shows” here

BBC: “Ovarian cancer: Screening may cut deaths by a fifth”  here

But a negative trial

“The primary analysis […] gave a[n ovarian cancer] mortality reduction over years 0–14 of 15% (95% CI –3 to 30; p=0·10) with [multi-modal screening] MMS and 11% (–7 to 27; p=0·21) with [ultrasound screening] USS.”

What happened?

The UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS) recruited post-menopausal women aged between 50 and 74.  50,639 were randomly assigned to undergo ovarian cancer screening by vaginal ultrasound (USS), 50,640 to ultrasound and CA125 blood testing, so called multi-modal screening (MMS) and 101,359 to be controls. The primary outcome, death due to ovarian cancer, analysis plans and sample size were all pre-specified and followed, and the results published in last week’s Lancet (click here or ukctocs)

Neither method worked (see above). But the small favourable trend in ovarian cancer deaths, which may have been an effect of chance, only appeared after seven years. Perhaps a true effect had been swamped by women who already had cancer when screened. The authors did a second data-driven analysis and concluded:

“Although the mortality reduction was not significant in the primary analysis, we noted a significant mortality reduction with MMS when prevalent cases were excluded. We noted encouraging evidence of a mortality reduction in years 7–14, but further follow-up is needed before firm conclusions can be reached on the efficacy and cost-effectiveness of ovarian cancer screening.”

First analysis fails so, having seen the data, have another go! And Ian Jacobs and Usha Menon, the two lead authors, hold shares in the company which owns the screening algorithm! And the lack of difference in all cause mortality (RR = 0.99, slightly favouring the control arm, albeit not remotely significant) was hidden deep in the appendix (Web table 6 UKCTOCS appendix). Is this spin?

There are two possible reasons why a screening test might appear to reduce one type of cancer-related death but not alter all cause mortality.

One reason is that ovarian cancer deaths are relatively rare, so even a real effect is swamped. The 45 deaths difference between the 347 ovarian cancer deaths among controls and the 302 among the two screened groups, amounts to only 0.33 percent of the overall 13,296 deaths in the trial.

The other is that a some deaths, which would have been classified as ovarian cancer in controls, get classified as something else in the screening group. This happened.  There were 11 deaths due to primary peritoneal cancer among controls but 21 in the treatment arms. Primary peritoneal cancer is the label we give ovarian cancer if the woman has already had her ovaries removed. Including these makes the primary analysis even less convincing.  MMS “ovarian or primary peritoneal mortality” reduction = 11% (95% CI –8 to 26; p=0·23) and USS = 9% (–9 to 24; p=0·31) (Table 3).

Once the primary peritoneal cancers are included, even exclusion of the prevalent cases leaves a difference which is no longer statistically significant. MMS “ovarian or primary peritoneal mortality” reduction = 18% (–1 to 34; p=0·064) and USS = 17% (–3 to 33; p=0·097) weighted log rank model (post hoc) excluding prevalent cases but including primary peritoneal (table 3).

To summarise

The trial showed a small reduction in ovarian cancer deaths which could have occurred by chance, and amounted to 0.33% of all deaths. After looking at the data and excluding prevalent cancers a different statistical test nominally indicated that the effect was unlikely to have occurred by chance. But they also found, as expected, that 11 women who died in the screening group of primary peritoneal cancer would have been classified as ovarian cancer deaths had they been in the control arm. So instead of nominally preventing 45 ovarian cancer deaths, the screening actually prevented only 35. Using these numbers, the difference, even with post hoc exclusion of prevalent cases, was no longer statistically significant.

Other trials

The only other big trial of ovarian cancer screening (PLCO) also showed no benefit. In that trial the direction was opposite; “118 deaths caused by ovarian cancer (3.1 per 10 000 person-years) in the intervention group and 100 deaths (2.6 per 10 000 person-years) in the usual care group (mortality RR, 1.18; 95% CI, 0.82-1.71).” The inclusion of these data will reduce nominal statistical significance still further.

Would it be worthwhile if true?

The present paper reports neither the human, time sitting in clinics undergoing blood tests or with a probe up your vagina, nor the economic costs. But here’s a “back of the envelope” calculation. If 100,000 women undergo 700,000 blood tests and 700,000 vaginal scans we might possibly save 35 lives. If each test takes up just half a day (appointments, travel, counselling, waiting, testing, going home and being given results) that would amount to 959 woman-years being screened.  The lives are only saved after between 7 and 14 years, so the beneficiaries will be between age 57 and 88. If optimistically each gained an average of 10 years, the programme would deliver 350 woman-years of benefit at the cost of spending 959 woman-years undergoing the screening.  Doubtless more sophisticated analyses will appear, but I’d advise scepticism if anyone claims the net benefits justify the costs.

Such blatant massaging of a positive conclusion out of a negative trial depressed me. But I was cheered by this excellent blog (click here) from Cancer Research UK, who had part funded the trial. It concludes:

“We don’t think there’s enough evidence for the NHS to introduce a national screening programme at this stage.”

Well said. The NHS will save hundreds of millions of pounds by not introducing this futile screening programme; money to spend on treatments which work. Nice trial. Happy Christmas.

Jim Thornton

 

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from → Health general, Questionable science, Trial Registry Troubles

Caesarean on demand

December 13, 2015
tags: Caesarean section, conscience clause, guidelines, NICE, on demand, parental choice, too posh to push

Better unsaid

In 2011 the National Institute for Clinical Excellence’s (NICE) Caesarean section guideline (here & NICECS) startled obstetricians; the authors had discovered a “right” to give birth that way.

“For women requesting a CS, if after discussion and offer of support (including
perinatal mental health support for women with anxiety about childbirth), a vaginal
birth is still not an acceptable option, offer a planned CS.”

Even NICE baulked at chaining a reluctant surgeon to the operating table, so they included a conscience clause:

“An obstetrician unwilling to perform a CS should refer the woman to an obstetrician who will carry out the CS.”

Some apologists have since claimed that NICE was referring to women with severe anxiety about vaginal birth, and indeed the guideline includes good advice about them, but it’s clear the recommendation also applies to women who request Caesarean for other reasons; those who for example believe it is safer, easier, or reduces perineal injury. The NICE authors didn’t like it, but the tabloids knew who they meant, women who believe it will keep their vaginas “honeymoon fresh” or are “too posh to push”.

NICE quoted well-established evidence of the safety of Caesarean for most women, and a tiny non-randomised study from Sweden (Wiklund et al., 2007) which they rightly judged as low quality. The latter suggested that Caesarean on maternal request was associated with a longer hospital stay but no difference in fetal risks, breast feeding at two days, maternal depression or rate of resumed coitus at three months.  It was associated with higher maternal satisfaction, but lower breast feeding and rate of planning another child at three months. An economic analysis, based on these flaky data found that vaginal delivery was £700 cheaper than maternal request Caesarean. It certainly wasn’t strong evidence that drove NICE’s advice. But it’s not really clear what did.

Perhaps, wanting to make a strong statement that women had the right to refuse Caesarean, they felt the need for symmetry. They did not cite any evidence that women were being refused maternal request Caesarean, they were more concerned about the opposite issue; that women were feeling bullied or scared into unnecessary ones. Many wise people argue that for reasons of convenience, money or pressure from lawyers with their own financial agendas, doctors are normalising Caesarean as a valid option for birth.

I guess I’m one of those doctors. I agree with NICE, that Caesarean is pretty safe for the mother. It may even be slightly safer for this baby. People have small families these days and we can usually deal with the complications. The evidence that it causes infertility, atopy or stillbirths in subsequent pregnancies is fairly weak. I worry that we may lose the skills for natural birth

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