Using an Electronic Nose to Predict Gastrointestinal Consequences of Pelvic Radiotherapy

Scientists have developed an instrument which works like an "electronic nose". It is able to "sniff" smells and separate different smells by their electronic "signature". Studies using an electronic nose strongly suggest that smelling samples taken from humans (e.g. urine/ stool/ sweat/ tears) can identify different electronic smell signature from people with different diseases and in the future might be a new and easier way to diagnose serious conditions at an earlier stage. In a very small study, it has been successfully shown that using an electronic nose to sniff a stool sample does seem to identify people before they have had any radiotherapy - who will go on to get serious bowel side effects of radiotherapy. If this finding is correct, this is very important as it would allow the cancer doctors the option to change the way they give radiotherapy if they knew that a person was at very high risk of serious side effects from the treatment and to start treatment for the side effects at a much earlier stage. In this study the investigators want to confirm in a larger study whether the previous findings are correct, and to see whether similar results can be obtained by sniffing urine rather than stool (that would be much easier for everyone) and identify exactly which part of the complicated "smell" signature is different in the people who will get side effects. This may lead for the investigators to able to identify why people are making this specific smell and then do something about changing the smell before treatment starts. The likeliest cause for the production of a smell which predisposes to side effects is a specific group of germs living in the bowel. If these germs can be identified, then there are many possible ways of changing these germ populations in advance of radiotherapy. Enormous improvements have been made in treating cancer in recent years leading to hugely improved survival, however, treatment not infrequently can lead to side effects. Of all