Immunogenicity of radiotherapy on bone metastases from prostate adenocarcinoma: What is the future for the combination with radiotherapy/immunotherapy?

Bone metastatic prostate cancers (PCa) are resistant to usual immunotherapies such as checkpoint inhibitors. The main hypothesis related to this immunoresistance is the lack of antigens to stimulate anti-tumor immunity. External radiation is a potential inducer antigens presentation and thus to immunotherapy proprieties. The aim of this review is to describe the tumor microenvironment specificities, especially in bone metastasis and the immune modifications after radiation therapy on a metastatic castration-resistant PCa population. PCa microenvironment is immunosuppressive because of many tumor factors. The complex interplay between PCa cells and bone microenvironment leads to a 'vicious circle' promoting bone metastasis. Furthermore, the immune and bone systems, are connected through an osteoclastogenic cytokine: the Receptor Activator Nuclear Factor Kappa B ligand. Adapted doses of ionizing radiation play a dual role on the tumor. Indeed, radiotherapy leads to immunogenicity by inducing damage associated with molecular patterns. However, it also induces an immunosuppressive effect by increasing the number of immunosuppressive cells. Interestingly, the abscopal effect could be used to optimize immunotherapy potential, especially on bone metastasis. Radiotherapy and immunotherapy combination is a promising strategy, however further studies are necessary to determine the more efficient types of radiation and to control the abscopal effect.

Local treatment in the setting of de novo metastatic rectal cancer: reappraisal of prognostic factors.

BACKGROUND: This retrospective study was conducted to: (1) provide more modern data on real-life local management of metastatic rectal cancer; (2) compare therapeutic strategies; and (3) identify prognostic factors of local failure, overall survival and progression-free survival. METHODS: Data about efficacy and acute toxicity were collected. Patients were diagnosed with metastatic rectal cancer between 2004 and 2015, and were treated at least with radiotherapy. Local failure, overall survival and progression-free survival were correlated with patient, tumour and treatment characteristics using univariate and multivariate analyses. RESULTS: Data of 148 consecutive patients with metastatic rectal cancer were analysed. Median follow-up was 19 months. Median overall survival was 16 months. All patients received local radiotherapy, with a median equivalent 2 Gy per fraction dose of 47.7 Gy. Rectal surgery was performed in 97 patients (65.6%). The majority of patients (86/97, 88.7%) received pre-operative chemoradiation. In multivariate analysis, rectal surgery was found to be the only independent predictor of increased overall survival (24.6 vs 7.1 months, p <0.001). Of the patients undergoing surgical treatment, 22.8% presented with significant complications that required a delay of systemic treatment. Grade 3-4 acute radiation therapy-related toxicities were observed in 6.1% of patients, mainly gastrointestinal toxicities (5.4%). CONCLUSION: Rectal surgery was a key predictive factor of increased progression-free survival and overall survival in patients receiving at least local radiotherapy. In our series of real-life patients, local surgery and radiation seemed as well tolerated as reported in selected phase III non-metastatic rectal cancer patients. These data suggested that local management could be beneficial for metastatic rectal cancer patients.

Outcome and prognostic factors in 593 non-metastatic rectal cancer patients: a mono-institutional survey.

This retrospective study was undertaken to provide more modern data of real-life management of non-metastatic rectal cancer, to compare therapeutic strategies, and to identify prognostic factors of overall survival (OS) in a large cohort of patients. Data on efficacy and on acute/late toxicity were retrospectively collected. Patients were diagnosed a non-metastatic rectal cancer between 2004 and 2015, and were treated at least with radiotherapy. OS was correlated with patient, tumor and treatment characteristics with univariate and multivariate analyses. Data of 593 consecutive non-metastatic rectal cancer patients were analyzed. Median follow-up was 41 months. Median OS was 9 years. Radiotherapy was delivered in pre-operative (n = 477, 80.5%), post-operative (n = 75, 12.6%) or exclusive (n = 41, 6.9%) setting. In the whole set of patients, age, nutritional condition, tumor stage, tumor differentiation, and surgery independently influenced OS. For patients experiencing surgery, OS was influenced by age, tumor differentiation and nodal status. Surgical resection is the cornerstone treatment for locally-advanced rectal cancer. Poor tumor differentiation and node involvement were identified as major predictive factor of poor OS. The research in treatment intensification and in identification of radioresistance biomarkers should therefore probably be focused on this particular subset of patients.

Outcomes prediction in pre-operative radiotherapy locally advanced rectal cancer: leucocyte assessment as immune biomarker.

OBJECTIVE: Leukocytes are hypothesized to reflect the inflammatory tumor microenvironment. We aimed to validate their prognostic significance in a large cohort of patients treated with pre-operative radiation for locally advanced rectal cancer (RC). RESULTS: From 2004 to 2015, 257 RC patients with available biological data underwent a pre-operative radiotherapy, with a median age of 66 years. The median rectal EQD2 was 49.2Gy. Most of patients experienced concurrent chemotherapy (n = 245, 95.4%), mainly with 5-FU (83.3%). Clear surgical margins (i.e. complete resection) were achieved in 234 patients (91.1%). A complete (Mandard TRG1: n = 35, 13.6%) or almost complete pathological response (Mandard TRG2: n = 56, 21.8%) were achieved in 91 patients (35.4%). With a median follow-up of 46.1 months, 8 patients (3.1%) experienced local relapse, 38 (14.8%) experienced metastases and 45 (17.5%) died. Elevated pre-radiation neutrophil to lymphocyte ratio (NLR > 2.8) was identified as an independent predictive factor of increased local relapse, of decreased progression-free survival and overall survival in multivariate analysis. Elevated NLR was marginally associated with incomplete pathological response in multivariate analysis, suggesting a possible value as a biomarker of radio-sensitivity. CONCLUSIONS: Pre-radiation NLR is a simple and robust biomarker for risk stratification in locally advanced RC patients undergoing pre-operative radiotherapy, and might select the subpopulation eligible to treatment intensification or to neoadjuvant chemotherapy. MATERIAL AND METHODS: Clinical records from consecutive patients treated in a single institution between 2004 and 2015 with curative-intent radiotherapy were retrospectively analyzed. Classical prognosis factors of RC and peripheral immune markers based on lymphocytes and neutrophil counts were studied.

[Care of Merkel cell carcinoma and role of the radiotherapy]. / Principe de prise en charge du carcinome à cellules de Merkel et place de la radiothérapie.

Merkel cell carcinoma is a rare neuro-endocrine tumor of skin with a poor prognosis. Data available in literature are scarce. Current treatment for locoregional disease is based on combined treatment by surgery and radiotherapy. However these treatments are controversial. The aim of the present review is to sum up the different available studies and to compare national and international guidelines.