Emerging Data on Biomarkers in ES TNBC

Joyce A. O’Shaughnessy, MD: Sara, could you just mention this interesting study from ESMO [European Society for Medical Oncology Congress]? It’s more of an interesting point of biology and not really a practice-changing thing about TIL [tumor-infiltrating lymphocyte] as a biomarker in some of these earlier-stage TNBCs [triple-negative breast cancers].

Sara A. Hurvitz, MD: Absolutely. There are actually a fair amount of data continuing to mount data that for tumor infiltrating lymphocytes, the presence of them is associated with an increasing chance of pathologic CR [complete response] and a better outcome in terms of recurrence rate and maybe even overall survival, specifically for the triple-negative breast cancer subtype. At ESMO, there was this nice paper from the Netherlands Cancer Registry, in which they looked at patients over many years—a good number of patients with triple negative breast cancer who unbelievably did not receive any systemic chemotherapy.

They had tumor samples and looked back to see how these patients did based on the percentage of TILs in the tumor. They subdivided it for patients with 30% to 74% and then 75% and above, and showed that the patients with less than 75% TILs present, stromal TILs we’re talking about now, in the tumor had a much worse recurrence-free survival and overall survival. Those patients who had greater than 75% or 75% or greater were in the high 90% with no chemotherapy. The suggestion is maybe we could be using this as a marker to help select patients for a de-escalation strategy. These patients didn’t even receive chemotherapy, and their cancer is essentially cured because there is enough time of follow up to know that it didn’t come back. How to measure TILs is a point of contention. There is a lot of intralaboratory variability.

There now are international consensus scoring recommendations that are published that we can use, but it’s a bit like Ki-67 and the early days of measuring ER [estrogen receptor] and PR [progesterone receptor], and it’s kind of the Wild West. You have to be careful if you’re going to be looking at this and doing research with it. It’s not something we’re using prime time, but if it does become a way for us to select patients for a de-escalation strategy or for the use of immunotherapy, it’s going to have to be standardized.

Joyce A. O’Shaughnessy, MD: Thank you. Right, very intriguing with a unique patient population that didn’t get any chemotherapy with node-negative disease and long follow-up. It’s really interesting, but as you said, maybe there could be a biomarker for de-escalation strategies for a future trial. Thanks, Sara.

Transcript Edited for Clarity