Peter Mac researchers have found a way to predict which patients with locally advanced rectal cancers might be diverted into a “watch and wait” group, potentially avoiding the need for lower bowel removal surgery and its life-long consequences. 

Most patients with this cancer have a course of chemoradiotherapy (chemotherapy plus radiotherapy) followed by major surgery to remove the tumour. 

In approximately 15-20% of cases,  the cancer may disappear after the chemoradiotherapy and it may be possible to avoid surgery completely and still cure the patient. 

The challenge is that it is currently impossible to either predict in which patients this is likely to happen, or to identify the patients in whom the cancer has disappeared without doing an operation to remove the bowel and look at it under the microscope. 

A new test, developed by Professors Robert Ramsay (pictured right) and Alexander Heriot (left) at Peter MacCallum Cancer Centre, has made it possible to identify those patients who have a powerful immune response after their chemoradiotherapy and who can safely delay any further surgery.

It works by assessing the potency of Tumour Infiltrating Lymphocytes (TILs) found in tumour-affected tissues. 

TILs are a group of cells which drive our immune response and their presence indicates the immune system is alert to cancer.  A study describing how the new test operates is published by the Journal of Clinical Oncology – Precision Oncology.

Professor Alexander HeriotRamsaysays the test should allow clinicians to identify those patients with locally advanced rectal cancer who can safely defer further surgery. 

“We are at the moment unable to identify that 15 to 20 per cent of patients who go through chemo and radiotherapy and it’s successful,” Prof Heriot says. 

“If we can identify these patients we can then put them in a ‘watch and wait’ category and monitor them without the need for surgery.

“The benefit to the patient is enormous in that we can both save the patient from having to undergo major surgery and also be able to divert the surgical resource to patients who do need surgery to cure them.”

The investigation involved 17 patients, all of whom had a biopsy evaluated before they started five weeks of chemo and radiotherapy followed by surgery some eight weeks after that.

Six out of the 17patients  - had a complete pathological response following chemo and radiotherapy, potentially negating the need for immediate surgical intervention.

“Two independent cancer pathologists looked at all the sections and saw only scar tissue and no tumour cells in six of the patients,” Prof Ramsay said. 

“With these results, in combination with cancer imaging and blood markers that detect tumour secretions, we feel we're in a position where we might be able to say, 'these patients have got a really good immune system, they are very likely to respond very well to the standard of care’.”

“So, we're pretty excited that we might be able to change practice and that's what one would hope with a translational research project.”

The small study is now being expanded to include both patients from Peter Mac and Western General. 

Read the full paperhttp://ascopubs.org/doi/10.1200/PO.18.00075