Immune Infiltration Test Predicts Cancer Relapse Risk

Estrogen receptor-positive (ER+) subtype accounts for about 80% of all breast cancers, the most common cancer in women. At diagnosis, the majority of ER+ patients have a good prognosis if treated with endocrine therapy.

A new test has been developed that can pick out women at high risk of relapsing from breast cancer within 10 years of diagnosis. The new test could help more accurately assess the risk of cancer returning in individual patients, and offer them monitoring or preventative treatment.

Scientists at the Institute of Cancer Research (London, UK) and their colleagues analyzed tissue samples from 1,178 women with the most common form of breast cancer, estrogen receptor positive breast cancer. The team created a new, fully automated computer tool to analyze the samples, which were taken as part of a clinical trial, comparing two hormone therapies that can help stop cancer recurring after surgery.

The team curated a digital database of hematoxylin and eosin (H&E) histology slides for the translational sub-study of the Arimidex, Tamoxifen, Alone or in Combination trial (TransATAC) and applied their histology image analysis pipeline. To evaluate the accuracy of the image analysis pipeline for TransATAC, a test set of 627 cells randomly sampled from three images was annotated by a pathologist blinded to image analysis results. The prognostic significance of immune scores was compared with Oncotype DX 21-gene recurrence score, PAM50 risk of recurrence score, the IHC4 score, and clinical treatment score, available for 963 patients.

The team found that scores of immune cell abundance were not associated with recurrence-free survival. In contrast, high immune spatial scores indicating increased cell spatial clustering were associated with poor 10-year, early (0–5 years), and late (5–10 years) recurrence-free survival. They discovered that when immune cells clustered together in hotspots, the chance of relapse within 10 years of starting treatment was 25% higher than when immune cells were evenly dispersed. The chance of cancer returning within five years was 23% higher in women with immune cell hotspots.

Paul Workman FMedSci, FRS, a professor and Chief Executive and President of The Institute of Cancer Research, said, “This ingenious new computer-based test automatically analyses breast cancer samples, revealing patterns impossible to detect under the microscope with the human eye. In future, the test could allow us to identify those patients who are at a higher risk of relapse on hormone therapy, and potentially change their treatment. What this study also tells us is that the immune system probably has a key role to play in how breast cancer responds to hormone treatment. Measuring the immune response to cancer could be important in future to help identify patients who could benefit from immunotherapy.” The study was published on August 4, 2017, in the Journal of the National Cancer Institute.

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