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Effect of Radiotherapy After Breast-Conserving Surgery Depending on the Presence of Tumor-Infiltrating Lymphocytes : A Long-Term Follow-Up of the SweBCG91RT Randomized Trial

Kovács, Anikó ; Stenmark Tullberg, Axel ; Werner Rönnerman, Elisabeth ; Holmberg, Erik ; Hartman, Linda LU ; Sjöström, Martin LU ; Lundstedt, Dan ; Malmström, Per LU ; Fernö, Mårten LU and Karlsson, Per (2019) In Journal of clinical oncology : official journal of the American Society of Clinical Oncology 37(14). p.1179-1187
Abstract

PURPOSE: The effects of radiotherapy (RT) on the basis of the presence of stromal tumor infiltrating lymphocytes (TILs) have not been studied. The purpose of this study was to analyze the association of TILs with the effect of postoperative RT on ipsilateral breast tumor recurrence (IBTR) in a large randomized trial. METHODS: In the SweBCT91RT (Swedish Breast Cancer Group 91 Radiotherapy) trial, 1,178 patients with breast cancer stage I and II were randomly assigned to breast-conserving surgery plus postoperative RT or breast-conserving surgery only and followed for a median of 15.2 years. Tumor blocks were retrieved from 1,003 patients. Stromal TILs were assessed on whole-section hematoxylin-eosin-stained slides using a dichotomized... (More)

PURPOSE: The effects of radiotherapy (RT) on the basis of the presence of stromal tumor infiltrating lymphocytes (TILs) have not been studied. The purpose of this study was to analyze the association of TILs with the effect of postoperative RT on ipsilateral breast tumor recurrence (IBTR) in a large randomized trial. METHODS: In the SweBCT91RT (Swedish Breast Cancer Group 91 Radiotherapy) trial, 1,178 patients with breast cancer stage I and II were randomly assigned to breast-conserving surgery plus postoperative RT or breast-conserving surgery only and followed for a median of 15.2 years. Tumor blocks were retrieved from 1,003 patients. Stromal TILs were assessed on whole-section hematoxylin-eosin-stained slides using a dichotomized cutoff of 10%. Subtypes were scored using immunohistochemistry on tissue microarray. In total, 936 patients were evaluated. RESULTS: Altogether, 670 (71%) of patients had TILs less than 10%. In a multivariable regression analysis with IBTR as dependent variable and RT, TILs, subtype, age, and grade as independent variables, RT (hazard ratio [HR], 0.42; 95% CI, 0.29 to 0.61; P < .001), high TILs (HR, 0.61; 95% CI, 0.39 to 0.96, P = .033) grade (3 v 1; HR, 2.17; 95% CI, 1.08 to 4.34; P = .029), and age (≥ 50 v < 50 years; HR, 0.55; 95% CI, 0.38 to 0.80; P = .002) were predictive of IBTR. RT was significantly beneficial in the low TILs group (HR, 0.37; 95% CI, 0.24 to 0.58; P < .001) but not in the high TILs group (HR, 0.58; 95% CI, 0.28 to 1.19; P = .138). The test for interaction between RT and TILs was not statistically significant (P = .317). CONCLUSION: This study shows that high values of TILs in the primary tumor independently seem to reduce the risk for an IBTR. Our findings further suggest that patients with breast cancer with low TILs may derive a larger benefit from RT regarding the risk of IBTR.

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Contribution to journal
publication status
published
subject
in
Journal of clinical oncology : official journal of the American Society of Clinical Oncology
volume
37
issue
14
pages
9 pages
publisher
American Society of Clinical Oncology
external identifiers
  • pmid:30939091
  • scopus:85065809648
ISSN
1527-7755
DOI
10.1200/JCO.18.02157
language
English
LU publication?
yes
id
c65168a5-61c9-4c40-8939-10dd06fe4dcc
date added to LUP
2019-05-28 10:43:40
date last changed
2020-02-26 07:27:02
@article{c65168a5-61c9-4c40-8939-10dd06fe4dcc,
  abstract     = {<p>PURPOSE: The effects of radiotherapy (RT) on the basis of the presence of stromal tumor infiltrating lymphocytes (TILs) have not been studied. The purpose of this study was to analyze the association of TILs with the effect of postoperative RT on ipsilateral breast tumor recurrence (IBTR) in a large randomized trial. METHODS: In the SweBCT91RT (Swedish Breast Cancer Group 91 Radiotherapy) trial, 1,178 patients with breast cancer stage I and II were randomly assigned to breast-conserving surgery plus postoperative RT or breast-conserving surgery only and followed for a median of 15.2 years. Tumor blocks were retrieved from 1,003 patients. Stromal TILs were assessed on whole-section hematoxylin-eosin-stained slides using a dichotomized cutoff of 10%. Subtypes were scored using immunohistochemistry on tissue microarray. In total, 936 patients were evaluated. RESULTS: Altogether, 670 (71%) of patients had TILs less than 10%. In a multivariable regression analysis with IBTR as dependent variable and RT, TILs, subtype, age, and grade as independent variables, RT (hazard ratio [HR], 0.42; 95% CI, 0.29 to 0.61; P &lt; .001), high TILs (HR, 0.61; 95% CI, 0.39 to 0.96, P = .033) grade (3 v 1; HR, 2.17; 95% CI, 1.08 to 4.34; P = .029), and age (≥ 50 v &lt; 50 years; HR, 0.55; 95% CI, 0.38 to 0.80; P = .002) were predictive of IBTR. RT was significantly beneficial in the low TILs group (HR, 0.37; 95% CI, 0.24 to 0.58; P &lt; .001) but not in the high TILs group (HR, 0.58; 95% CI, 0.28 to 1.19; P = .138). The test for interaction between RT and TILs was not statistically significant (P = .317). CONCLUSION: This study shows that high values of TILs in the primary tumor independently seem to reduce the risk for an IBTR. Our findings further suggest that patients with breast cancer with low TILs may derive a larger benefit from RT regarding the risk of IBTR.</p>},
  author       = {Kovács, Anikó and Stenmark Tullberg, Axel and Werner Rönnerman, Elisabeth and Holmberg, Erik and Hartman, Linda and Sjöström, Martin and Lundstedt, Dan and Malmström, Per and Fernö, Mårten and Karlsson, Per},
  issn         = {1527-7755},
  language     = {eng},
  number       = {14},
  pages        = {1179--1187},
  publisher    = {American Society of Clinical Oncology},
  series       = {Journal of clinical oncology : official journal of the American Society of Clinical Oncology},
  title        = {Effect of Radiotherapy After Breast-Conserving Surgery Depending on the Presence of Tumor-Infiltrating Lymphocytes : A Long-Term Follow-Up of the SweBCG91RT Randomized Trial},
  url          = {http://dx.doi.org/10.1200/JCO.18.02157},
  doi          = {10.1200/JCO.18.02157},
  volume       = {37},
  year         = {2019},
}