Correlation between radio-induced lymphocyte apoptosis measurements obtained from two French centres

International audiencePURPOSE OF THE RESEARCH:In the era of modern treatment delivery, increasing the dose delivered to the target to improve local control might be modulated by the patient's intrinsic radio-sensitivity. A predictive assay based on radio-induced lymphocyte apoptosis quantification highlighted the significant correlation between CD4 and CD8 T-lymphocyte apoptosis and grade 2 or 3 radiation-induced late toxicities. By conducting this assay at several technical platforms, the aim of this study was to demonstrate that radio-induced lymphocyte apoptosis values obtained from two different platforms were comparable.MATERIALS AND METHODS:For 25 patients included in the PARATOXOR trial running in Dijon the radio-induced lymphocyte apoptosis results obtained from the laboratory of Montpellier (IRCM, Inserm U1194, France), considered as the reference (referred to as Lab 1), were compared with those from the laboratory located at the Institut de cancérologie de Lorraine (ICL, France), referred to as Lab 2. Different statistical methods were used to measure the agreement between the radio-induced lymphocyte apoptosis data from the two laboratories (quantitative data). The Bland-Altman plot was used to identify potential bias.RESULTS:All statistical tests demonstrated good agreement between radio-induced lymphocyte apoptosis values obtained from both sites and no major bias was identified.CONCLUSIONS:Since radio-induced lymphocyte apoptosis values, which predict tolerance to radiotherapy, could be assessed by two laboratories and showed a high level of robustness and consistency, we can suggest that this assay be extended to any laboratories that use the same technique

Etude LYMPHOREC. Réponse immunitaire intra-tumorale à la radiothérapie préopératoire pour des cancers du rectum de stades II-III: nouveau paramètre pronostic de la survie des patients

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Absolute volume of the rectum and AUC from rectal DVH between 25Gy and 50Gy predict acute gastrointestinal toxicity with IG-IMRT in prostate cancer

International audienceBackground: To determine whether dose/volume specific endpoints (DVSE) or Area under the rectal DVH curve (rAUC) better predict acute gastrointestinal (GI) toxicity in prostate cancer patients treated with IMRT in the era of daily image guidance (IG-IMRT). Methods: A set of DVSE was recorded from V25 to V75 (increments of 5Gy) (both in % and in cc) for 180 men. The rAUC was calculated for doses ranging between 25Gy and 50Gy (rAUC(25-50)). Univariate and multivariate logistic regressions were performed to determine the relationship between DVSE or rAUC(25-50) and the appearance of any acute GI toxicity. Results: The rates of acute grade 1 (G1), G2 and G3 GI toxicities were 53.3 %, 10.6 % and 1.1 %, respectively. No G4 + toxicity was observed. Rectal V25 to V75 expressed in % were not predictive of G >= 1 GI toxicity (p >= 0.12) whereas rectal V25 to V50 expressed in cc did correlate with GI toxicity G >= 1 (p >= 0.04). rAUC(25-50) expressed in cc. Gy correlated significantly with the occurrence of any acute GI toxicity G >= 1 (p = 0.027). Conclusions: The absolute volume of the rectum between 25Gy and 50Gy and rAUC(25-50) could significantly predict any acute rectal toxicity in prostate cancer patients treated with daily IG-IMRT

Tumoral lymphocyte immune response to preoperative radiotherapy in locally advanced rectal cancer as a prognostic factor for survival: the LYMPHOREC study

Présentation PosterInternational audienceBackground: Short-course preoperative radiotherapy (sc-preopRT) and long-course preoperative radiotherapy (lc-preopRT) followed by total mesorectal excision (TME) are worldwide standards of care in locally advanced T3–4 N0 or N1 rectal adenocarcinoma. It is now well established that the host immune system participates in the elimination of tumor cells and that significant tumor infiltration by T-cells (LT), such as CD8+, is associated with a better prognosis. In colorectal tumors, the infiltration of Treg FoxP3+ is also described as a prognostic factor associated with better survival. We aimed to investigate the impact of the immune response to preoperative RT on progression-free survival (PFS) and overall survival (OS) in rectal cancer managed with TME.Material and Methods: We analyzed data for 237 patients with rectal cancer who underwent TME between 1995 and 2007 after neo-adjuvant treatment with preoperative RT with or without CT in 3 French centers. The LYMPHOREC study was approved by the French national review boards and independent ethics committee (CPP, CCTIRS and the CNIL). Our primary objective was to assess the impact of the immune infiltration of the tumor or tumor site (in cases with complete response) by CD8+ and FoxP3+ lymphocytes after sc-preopRT or lc-preopRT with or without CT on progression-free survival (PFS) and overall survival (OS). Our secondary objectives were to assess changes in the quantities of these lymphocyte infiltrations with respect to the type of preoperative RT (with vs without chemotherapy) or the dose fractionation scheme (≤2Gy vs >2Gy/fraction). These second analyses were performed with 133 patients from whom one biopsy sample was collected. A biopsy-based pretherapeutic lymphocyte infiltration was thus evaluated.Results: In univariate analysis, TNM stage, the delay between surgery and RT, CD8+, FoxP3+ and the ratio CD8+/FoxP3+ were significantly correlated with survival outcomes while chemotherapy as a component of preoperative radiotherapy was not. In multivariate analysis, when adjusted for clinical and treatment-related variables, tumor infiltration by FoxP3 lymphocytes after treatment significantly correlated with PFS (p=0.007). Variations in the CD8/FoxP3 ratio inside the epithelial tissue from before to after preoperative RT correlated with PFS and OS (p=0.049 and p=0.024, respectively). Interestingly, the dose per fraction (<2Gy vs. ≥2Gy) significantly influenced the CD8/FoxP3 ratio after treatment (p=0.027) with a lower ratio with hypofractionated RT.Conclusions: Patients with rectal cancer who had a significant decrease in the CD8/FoxP3 ratio after preoperative radiotherapy had better survival outcomes. The CD8/FoxP3 ratio needs to be validated prospectively. The immune response to preoperative RT may guide physicians in the decision to give adjuvant treatment to patients with rectal cancer