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EBioMedicine. 2015 Oct 25;2(12):1965-73. doi: 10.1016/j.ebiom.2015.10.024. eCollection 2015 Dec.

Radiation-induced CD8 T-lymphocyte Apoptosis as a Predictor of Breast Fibrosis After Radiotherapy: Results of the Prospective Multicenter French Trial.

Author information

1
Montpellier Cancer Institute (ICM), Montpellier Cancer Research Institute (IRCM), University of Montpellier, Montpellier, France.
2
Institut Jean Godinot, Reims, France.
3
Centre GF Leclerc, Dijon, France.
4
AP-HP Henri Mondor, Créteil, France.
5
Institut Curie, Paris, France.
6
Centre Oscar Lambret, Lille, France.
7
Gustave Roussy, Villejuif, France.
8
Centre Paul Strauss, Strasbourg, France.
9
Centre Marie Curie, Valence, France.
10
Centre Hospitalier Lyon Sud, Pierre Bénite, France.
11
AP-HP Saint-Louis, Paris, France.
12
Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland.

Abstract

BACKGROUND:

Monocentric cohorts suggested that radiation-induced CD8 T-lymphocyte apoptosis (RILA) can predict late toxicity after curative intent radiotherapy (RT). We assessed the role of RILA as a predictor of breast fibrosis (bf +) after adjuvant breast RT in a prospective multicenter trial.

METHODS:

A total of 502 breast-cancer patients (pts) treated by conservative surgery and adjuvant RT were recruited at ten centers. RILA was assessed before RT by flow cytometry. Impact of RILA on bf + (primary endpoint) or relapse was assessed using a competing risk method. Receiver-operator characteristic (ROC) curve analyses were also performed in intention to treat. This study is registered with ClinicalTrials.gov, number NCT00893035 and final analyses are presented here.

FINDINGS:

Four hundred and fifty-six pts (90.8%) were included in the final analysis. One hundred and eight pts (23.7%) received whole breast and node irradiation. A boost dose of 10-16 Gy was delivered in 449 pts (98.5%). Adjuvant hormonotherapy was administered to 349 pts (76.5%). With a median follow-up of 38.6 months, grade ≥ 2 bf + was observed in 64 pts (14%). A decreased incidence of grade ≥ 2 bf + was observed for increasing values of RILA (p = 0.012). No grade 3 bf + was observed for patients with RILA ≥ 12%. The area under the ROC curve was 0.62. For cut-off values of RILA ≥ 20% and < 12%, sensitivity and specificity were 80% and 34%, 56% and 67%, respectively. Negative predictive value for grade ≥ 2 bf + was equal to 91% for RILA ≥ 20% and positive predictive value was equal to 22% for RILA < 12% where the overall prevalence of grade ≥ 2 bf + was estimated at 14%. A significant decrease in the risk of grade ≥ 2 bf + was found if patients had no adjuvant hormonotherapy (sHR = 0.31, p = 0.007) and presented a RILA ≥ 12% (sHR = 0.45, p = 0.002).

INTERPRETATION:

RILA significantly predicts the risk of breast fibrosis. This study validates the use of RILA as a rapid screening test before RT delivery and will change definitely our daily clinical practice in radiation oncology.

FUNDING:

The French National Cancer Institute (INCa) through the "Program Hospitalier de Recherche Clinique (PHRC)".

KEYWORDS:

Apoptosis; Breast fibrosis; Lymphocyte; Prediction; Radiotherapy

PMID:
26844275
PMCID:
PMC4703704
DOI:
10.1016/j.ebiom.2015.10.024
[Indexed for MEDLINE]
Free PMC Article

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