Sample size in clinical trials

[Guest guest]

Sammy recently regretted that some cancer trial results were

published even though there were only 68 patients in the trial.

Of course he's right.

One problem however is the expense. The drug company (or whoever

is funding the research) has to pay something for every patient.

It could be a lot per patient. For surgery and radiation trials

it could be tens of thousands of dollars per patient, but even

for drug trials, the sponsor normally has to pay for the drugs,

the doctors to administer them, the pre-treatment testing, the

post-treatment testing, and the follow-up. Thousands of dollars

per patient seems more than likely to me.

Another problem is the lack of patients.

I was in a Phase II clinical trial that was hoping to enroll 30

patients. They decided that the rock bottom minimum they could

enroll and still publish results was 18.

They only recruited 14, in spite of the fact that the trial was

for an extension of a known effective treatment, and was totally

free, and was offered in the Washington DC area where there are

plenty of available patients, including many without health

insurance who could not afford private treatment.

So we often don't get high confidence, high statistical

significance information. We are left with a choice between

information with less confidence and less statistical

significance, or no information at all. I'm grateful to the

universities, the companies, the doctors, and the patients, who

are doing what they do to get us at least that much.

But I don't have to tell cancer patients about ambiguous

information. We've all had to deal with it.

Alan

[Guest guest]

Alan and Sammy

68 patients who got benefit, when none were reported as having no benefit looks like the drug is worth following up, with at least little more research.

They are either the only 68 patients in the world that get benefit, representatives of a substantial number or the drug is universally beneficial.

At certain times in their cancer lives as most if not all options have been tried, we get ready to try "owt". It is those folk who have most interest in these kinds of trails with these kinds of figures, especially if there is little or no side effects.

One of the really important things that we need to look at in those circumstances is what criteria was used for selection of patients in the trial

Sample size in clinical trials

Sammy recently regretted that some cancer trial results werepublished even though there were only 68 patients in the trial.Of course he's right.One problem however is the expense. The drug company (or whoeveris funding the research) has to pay something for every patient.It could be a lot per patient. For surgery and radiation trialsit could be tens of thousands of dollars per patient, but evenfor drug trials, the sponsor normally has to pay for the drugs,the doctors to administer them, the pre-treatment testing, thepost-treatment testing, and the follow-up. Thousands of dollarsper patient seems more than likely to me.Another problem is the lack of patients.I was in a Phase II clinical trial that was hoping to enroll 30patients. They decided that the rock bottom minimum they couldenroll and still publish results was 18.They only recruited 14, in spite of the fact that the trial wasfor an extension of a known effective treatment, and was totallyfree, and was offered in the Washington DC area where there areplenty of available patients, including many without healthinsurance who could not afford private treatment.So we often don't get high confidence, high statisticalsignificance information. We are left with a choice betweeninformation with less confidence and less statisticalsignificance, or no information at all. I'm grateful to theuniversities, the companies, the doctors, and the patients, whoare doing what they do to get us at least that much.But I don't have to tell cancer patients about ambiguousinformation. We've all had to deal with it.Alan

[Guest guest]

' " owt " for " nowt " '

Am J Clin Oncol. 1997 Feb;20(1):40-5.

Treatment of metastatic carcinoma of the prostate.

Goethuys H, Baert L, Van Poppel H, Lieskovsky G, Brady LW, Petrovich Z.

Department of Urology, Catholic University of Leuven, Belgium.

Disseminated carcinoma of the prostate (CaP) is a common manifestation of this

disease. Metastatic CaP in the United States is seen in about 45,000 patients

each year at diagnosis. At least the same number of patients who have had prior

definitive treatment with surgery or radiotherapy develop evidence of metastatic

disease. Hormonal management is the most important and well established

treatment for patients with prostatic metastases. Orchiectomy remains the most

efficient and most cost effective therapy in a rapid ablation of testicular

androgens. Due to a well known psychological reaction to castration which is

seen in many patients, diethylstilbestrol (DES) is a good alternative and cost

effective therapy. The mode of action of DES is to suppress LH production and to

slowly, indirectly, decrease serum testosterone level. In recent years, total

androgen blockade (TAB) has become a widely accepted treatment option. This

treatment has been shown in several clinical trials to be effective and well

tolerated by the patients. A major problem with a routine use of TAB is a

relatively high cost of this therapy. In a European prospective randomized

trial, goserelin acetate-flutamide combination significantly increased time to

progression when compared with orchiectomy alone. Patients with localized and

symptomatic metastases are best treated with radiotherapy. Those with multiple

sites of involvement are best treated with strontium-89 which results in a good

palliation in a majority of patients. Nearly all hormonally treated patients,

with metastatic CaP, eventually show tumor progression. Presently available

chemotherapy is of a low effectiveness and should not be used for these patients

outside of controlled clinical trials. Current research is directed to identify

effective therapy for hormone refractory patients. Immunotherapy and gene

therapy may be useful future therapeutic options.

PMID: 9020286 [PubMed - indexed for MEDLINE]

>

> Alan and Sammy

>

> 68 patients who got benefit, when none were reported as having no benefit

looks like the drug is worth following up, with at least little more research.

>

> They are either the only 68 patients in the world that get benefit,

representatives of a substantial number or the drug is universally beneficial.

>

> At certain times in their cancer lives as most if not all options have been

tried, we get ready to try " owt " . It is those folk who have most interest in

these kinds of trails with these kinds of figures, especially if there is little

or no side effects.

>

> One of the really important things that we need to look at in those

circumstances is what criteria was used for selection of patients in the trial

>

>

>

>

>

>

> Sample size in clinical trials

>

>

>

> Sammy recently regretted that some cancer trial results were

> published even though there were only 68 patients in the trial.

>

> Of course he's right.

>

> One problem however is the expense. The drug company (or whoever

> is funding the research) has to pay something for every patient.

> It could be a lot per patient. For surgery and radiation trials

> it could be tens of thousands of dollars per patient, but even

> for drug trials, the sponsor normally has to pay for the drugs,

> the doctors to administer them, the pre-treatment testing, the

> post-treatment testing, and the follow-up. Thousands of dollars

> per patient seems more than likely to me.

>

> Another problem is the lack of patients.

>

> I was in a Phase II clinical trial that was hoping to enroll 30

> patients. They decided that the rock bottom minimum they could

> enroll and still publish results was 18.

>

> They only recruited 14, in spite of the fact that the trial was

> for an extension of a known effective treatment, and was totally

> free, and was offered in the Washington DC area where there are

> plenty of available patients, including many without health

> insurance who could not afford private treatment.

>

> So we often don't get high confidence, high statistical

> significance information. We are left with a choice between

> information with less confidence and less statistical

> significance, or no information at all. I'm grateful to the

> universities, the companies, the doctors, and the patients, who

> are doing what they do to get us at least that much.

>

> But I don't have to tell cancer patients about ambiguous

> information. We've all had to deal with it.

>

> Alan

>