The number of Tumour Infiltrating Lymphocytes (TILs) detected in a patient’s early-stage breast cancer can indicate how well they will respond to treatment, new analysis has confirmed.

Researchers led by Peter Mac’s Professor Sherene Loi pooled the results of nine studies in which these immune cells were counted in more than 2,100 samples of early-stage Triple Negative Breast cancer (TNBC).

TILs are immune cells that include killer T-cells and other white blood cells, and a higher TILs count indicates the patient’s immune system is rallying a response to their cancer.

“What this analysis has confirmed is that patients with the most TILs in their tumour sample, taken at diagnosis, go on to have better outcomes at three years after adjuvant treatment,” says Prof Loi.

“This has confirmed the usefulness of quantitating TILs in early-stage TNBC as this information provides a signal as to how the patient will respond to conventional treatment, helping us to optimise existing next-generation treatments.

“This includes identifying those patients who are most likely to do well and those who are most likely to relapse early and who may benefit from additional interventions.”

Results of the study – the largest pooled analysis of its type – were published in the Journal of Clinical Oncology this month.

Patients involved in the pooled analysis were aged from 22 to 85 years, with an average age of 50 years. For most (77%), their breast cancer had spread to also include lymph nodes.

Those with the lowest TILs counts were generally older, had larger tumours, and were more likely to have their breast cancer spread to their lymph nodes.

In those with the highest TILs counts and no lymph node involvement, disease-free survival was 92% and overall survival was 99% three years after treatment.

The study also represents a major collaboration between Peter Mac and the Gustave Roussy cancer institute in Paris, France, where the research was led by Dr Stefan Michiels.

A web-based tool has been created to help clinicians to assess estimates of survival including TILs and other clinical factors in their patients.

Read the paper titled “Tumor-Infiltrating Lymphocytes and Prognosis: A Pooled Individual Patient Analysis of Early-Stage Triple-Negative Breast Cancers” here: https://doi.org/10.1200/JCO.18.01010

Also, go online to www.tilsinbreastcancer.org to access the tool and for more information on how to quantitate TILs using the published method.