Comment Re: Glucose-Ketone Index (GKI) tracking for dieta (Score 1) 54
You can't blind a trial where your diet is a 3:1 ratio of fats to non-fats. There just no sugar pill for that. There's no self-selection here either- just eligibility evaluation followed by informed consent (because people are not mice). A placebo control arm would be immoral due to the pace of this disease leaving no option for crossover.
As for sample size, the sheer size of the effect blows away your objection. Ask yourself this: "There are 18 glioblastoma patients. Seven of them have stayed alive 33, 36, 36, 84, 43 and 44 months after diagnosis. Calculate the odds of this occuring by chance". Answer: 0.1 to 1.2%, making it extremely unlikely to happen by chance. Even if you add 2 more people to N (assuming they were ineligible due to comorbidities), the answer stays the same: VERY UNLIKELY. This is even before you analyse the compliant subgroup.
Small N is not a problem when the "Effect Size" is this large. In statistics, if you are looking for a tiny 2% improvement in survival, you need thousands of patients to prove it isn't an accident. But if your effect size is massive like this one is, you only need a small group. A 3-year survival rate jumping from 8% to 58% (compliant subgroup), or even from 8% to 25% (naive analysis of overall group) is a massive signal. It is like testing a parachute: you donâ(TM)t need a randomized trial of 10000 people jumping out of planes with and without parachutes to prove they work; the effect size of the parachute is immediately obvious in a small sample jumping with parachutes (It's also the moral trial to do).