Can we have predictors of radiation response?

Ever since I started my career as a rad-onc trainee, I have always been tantalised by the idea of personalised radiation therapy (and cancer therapeutics). I could write tomes of material on how to achieve it. I think it actually represents the holy grail of radiation therapy.

However, there is no marketing hype behind the hypoxic fraction, and the brightest minds in biology are fixated on the next big breakthrough of finding targeted mutations. It may work with radiation, but the fractionation scheme is still largely empirical.

Consider the following simplistic idea:

image-10-12-19-at-18.35

This idea had remained with me even before the genome-wide association studies became fashionable.

Of course, I realised that it is just not a simplistic plating of the tumours from the visible fraction (may or may not be necrotic). A lot has to account for plating efficiency (nearly 70% of the cells are lost), and it requires “standard experimental conditions in the lab” to maintain it’s integrity.

I haven’t lost the sight, and as my senior predicted, I get incredibly excited by the gene chips. That’s the “real-dope”; genuinely fascinating one. In-vivo is even more complex molecular soup, but then radiation oncology is pure magic, anyway (and the practitioners as wizards).

I will be putting up chapters from the biology textbook (5th edition of my all-time favourite Basic Clinical Radiation Biology). As usual, the idea is to assist the trainees in getting the gist of the chapter that would put them in a better frame. Please feel free to download the PDF’s from the embedded Scribd links. (I am not happy with the way it renders itself, but it should be possible to open in the standard PDF reader).