Does delayed time from diagnosis till treatment affect survival?

[Tzippy Shochat]

Dear Medstatters.

I am currently involved in a study about the effect of delayed treatment on survival.

I perused several articles on this subject,

The articles, which gave information on the starting time for survival analysis, used Treatment Start as the starting time.

See here, for instance: https://ashpublications.org/blood/article/136/7/823/460669/Does-time-from-diagnosis-to-treatment-affect-the.

My concern is this:

Even if the treatment does not work, simply delaying treatment will cause less time to pass from treatment start till death, and falsely attribute a negative effect of delaying treatment on survival.

I think survival time, for these type of studies, should be from the Diagnosis Date (not the Treatment Date).

Is my thinking correct?

Thanks

Tzippy Shochat

[Abhaya Indrayan]

Even if you start from the diagnosis date, the problem remains if the treatment is ineffective. The delayed treatment will make an impact on survival only for effective treatment, that too under certain stability conditions.

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Dr Abhaya Indrayan, MSc,MS,PhD(OhioState),FSMS,FAMS,FRSS,FASc

Personal website: http://indrayan.weebly.com

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[MANOJ KUMAR]

Treatment works late to reach that means it is something clinical issues like immediate-release or extended-release formulation... 

may be clinical investigators need to look at the protocol and take a step accordingly 

Dr. Manoj 

University of Pittsburgh 

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Best Regards,

Dr. Manoj Kumar Diwakar, M.Sc., M.Phil.,Ph.D. (Statistics)
Assistant Professor
Centre for Economic Studies & Planning (CESP), School of Social Sciences (SSS-II),
Jawaharlal Nehru University, New Delhi-110067, India. 

Email id: manojkumar@jnu.ac.in 

 Mobile-09990346151

Area of Specialisation: Statistics, Econometric and Applied Mathematics 

Research Methodology -Quantitative Methods, Health Economics, Clinical Trial-Biostatistics

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