Thousands of individuals with bowel most cancers may very well be spared radiotherapy on prime of chemotherapy after a examine discovered it didn't have an effect on their survival probabilities.

Patients usually bear chemotherapy and radiotherapy earlier than surgical procedure to shrink tumours, making them simpler to take away and decreasing the danger of recurrence.

But researchers found rectal most cancers sufferers might skip radiotherapy – which might trigger nasty long-term unwanted side effects – in the event that they responded nicely to chemo.

Study chief Dr Deb Schrag, of Memorial Sloan Kettering Cancer Center in New York, stated the findings had been “a big deal because we have been radiating pelvises to treat this type of rectal cancer for the past 30 years”.

She stated most “intermediate risk” rectal most cancers sufferers could be handled with out pelvic radiation, including: “[It] has real toxicities. It impairs bowel, bladder and sexual function and has increased risk of pelvic fractures and secondary cancers.”

Around 43,000 individuals are identified with bowel most cancers every year within the UK. Rectal most cancers is the most typical subtype, accounting for 20-30 p.c of instances.

The examine concerned 1,194 sufferers with superior rectal most cancers. Half acquired the usual remedy of chemoradiation adopted by surgical procedure.

The relaxation began with simply chemo. If tumours shrank by not less than a fifth, they went on to surgical procedure. If not, that they had chemoradiation as standard, then an op.

Five years later, 79 p.c of sufferers within the standard care group had been disease-free, in contrast with 81 p.c within the different group.

Only 9 p.c of these within the second remedy group didn't see their tumours shrink sufficient after chemo and wanted radiotherapy.

Common unwanted side effects of radiotherapy additionally embody sore pores and skin, bladder issues, tiredness and infertility.

Dr Pamela Kunz, of the American Society of Clinical Oncology which hosted the Chicago convention the place the analysis was offered, stated it ought to change the way in which docs deal with this most cancers.

She defined: “As we develop new therapies, we are exploring where we can eliminate toxic therapies for our patients. The findings of this study allow us to do just that.”

Prof Charles Swanton, Cancer Research UK’s chief clinician, stated medics had been eager to scale back drug or radiation publicity to chop unwanted side effects. He defined: “Pelvic radiotherapy is associated with major long-term side effects. Avoiding radiation is a major step forward.”

He added: “It’s also excellent for NHS resources, being able to avoid radiation and free up radiotherapy slots for other patients.”