nos-trum. pronunciation: \nos'-trum\. noun. Etymology: Latin, neuter of noster our, ours.
1. a medicine of secret composition recommended by its preparer but usually without scientific proof of its effectiveness.
2. a usually questionable remedy or scheme.
See here for more discussion.

Friday, September 3, 2010

Drugs For Osteoporosis: Dueling Research About Risk Of Esophageal Cancer

Very important research to watch as it develops, for those women who take drugs for low calcium in their bones.  But, the worst case scenario  is that the risk of cancer is still low.

This is typical for how science advances: studies will give opposite results, and sometimes there is a clue to the real answer in the methodological differences.

Disorders of bone metabolism, particularly in ageing, and most particularly in women, are disabling and potentially life threatening.  Collapsed spinal column structures, easily fractured bones...all are very serious.  So medicines that will preserve calcium, and hence bone strength are critical for some patients.  Many patients take these medications, called "bisphosphonates."

To see the study that shows no effect on risk of throat cancer from bisphosphonates (Fosamax, Actonel, Boniva, and others) go here.

For the study that show an increased risk of throat cancer go here.

The fascinating thing about these studies is...they both used the same patient database.

So, why the different result?  Well, in the second (increased risk) study, the patients had been on the drugs longer.  Maybe that's it.  Too soon to tell.

For Onion Peelers:
1.  Here's the data on the "no increased risk" study.
Mean follow-up time was 4.5 and 4.4 years in the bisphosphonate and control cohorts, respectively. One hundred sixteen esophageal or gastric cancers (79 esophageal) occurred in the bisphosphonate cohort and 115 (72 esophageal) in the control cohort. ..the incidence of esophageal cancer alone in the bisphosphonate and control cohorts was 0.48 and 0.44 per 1000 person-years of risk, respectively. ...(adjusted hazard ratio, 1.07 [95% confidence interval, 0.77-1.49]).

2.  Here's the data on the increased risk study:
The incidence of oesophageal cancer was increased in people with one or more previous prescriptions for oral bisphosphonates compared with those with no such prescriptions (relative risk 1.30, 95% confidence interval 1.02 to1.66; P=0.02). Risk of oesophageal cancer was significantly higher for 10 or more prescriptions (1.93, 1.37 to 2.70) than for one to nine prescriptions (0.93, 0.66 to 1.31) (P for heterogeneity=0.002), and for use for over 3 years (on average, about 5 years: relative risk v no prescription, 2.24, 1.47 to 3.43).

If you slogged your way through all of that, you might be asking yourself, "why can't these people study things using the exact same way of analyzing the data, so we don't have to puzzle it out?"  I can't answer that.

What's not easy to see that having "10 or more prescriptions" is one way of saying how long somebody has been taking the medicine (maybe the British like that way of putting it...this was a UK study.)

Finally, let's sweep away all the detail, and just assume that the "increased risk" study is true.  If you do some other analysis, what we're talking about here is going from approximately 1 in 1000 risk to 2 in 1000 risk by taking the bisphosphonates.

By comparison, for the elederly who have severe bone loss and suffer a hip fracture, the fatality rate is about 50%.

So, take your choice.  Patients shouldn't rush to judgment yet.  Talk to your doctor.

Doc D

1 comment:

WarmSocks said...

Thanks so much for posting things like this.

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