Tumor-Infiltrating Lymphocytes Exhibit Prognostic Value in Low-Risk Ductal Carcinoma in Situ

Analysis of findings from the late-20th century SweDCIS phase 3 randomized radiotherapy trial revealed the prognostic efficacy of tumor-infiltrating lymphocytes (TILs) in patients with low-risk ductal carcinoma in situ (DCIS), associating TILs with a higher recurrence risk in patients with human epidermal growth factor receptor 2 (HER2)-negative DCIS.

“In invasive breast cancer, assessment of TILs provides prognostic and predictive information. However, the clinical impact of TILs for DCIS has not yet been demonstrated,” wrote Aglaia Schiza, MD, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden, and co-authors.

This current analysis of the more than 20-year-old study assessed TILs on hematoxylin-eosin sections (n = 711) with scores analyzed by either continuous or dichotomized (≤5% versus >5%) variable with the primary endpoint of ipsilateral breast events (IBEs) predefined. More patients exhibited TILs prevalence of ≤5% (61.9%) than >5% (38.1%).

According to findings of the study, high TILs-scores were associated with larger lesion size, HER2-positivity, higher nuclear grade, and Ki-67-score. Five years after surgery, DCIS patients with high TILs prevalence experienced significantly increased cumulative IBE incidence (low TILs and high TILs 9% vs 18%, respectively; P < 0.001).

In multivariable analysis with an adjusted hazard ratio of 2.41 (95% confidence interval [CI], 1.17 to 4.95, P = 0.017), high TILs proved an independent poor prognosis marker for IBE risk in patients with HER2-negative DCIS. Patient TILs-status exhibited no relationship to radiotherapy benefit.

Study authors concluded, “Our data indicate that TILs should be integrated into the clinical workup to define patients with low-risk DCIS who can omit adjuvant therapy or patients with potential benefits from immunotherapy.”

Source:

Schiza A, Thurfjell V, Stenmark Tullberg A, et al. Tumour-infiltrating lymphocytes add prognostic information for patients with low-risk DCIS: Findings from the SweDCIS randomised radiotherapy trial. Eur J Cancer. 2022;168:128-137. doi:10.1016/j.ejca.2022.01.016