Molecular signature of response to preoperative radiotherapy in locally advanced breast cancer.

BACKGROUND: Radiation therapy is an indispensable part of various treatment modalities for breast cancer. Specifically, for non-inflammatory locally advanced breast cancer (LABC) patients, preoperative radiotherapy (pRT) is currently indicated as a second line therapy in the event of lack of response to neoadjuvant chemotherapy. Still approximately one third of patients fails to respond favourably to pRT. The aim of this study was to explore molecular mechanisms underlying differential response to radiotherapy (RT) to identify predictive biomarkers and potential targets for increasing radiosensitivity. METHODS: The study was based on a cohort of 134 LABC patients, treated at the Institute of Oncology and Radiology of Serbia (IORS) with pRT, without previous or concomitant systemic therapy. Baseline transcriptional profiles were established using Agilent 60 K microarray platform in a subset of 23 formalin-fixed paraffin-embedded (FFPE) LABC tumour samples of which 11 radiotherapy naïve and 3 post-radiotherapy samples passed quality control and were used for downstream analysis. Biological networks and signalling pathways underlying differential response to RT were identified using Ingenuity Pathways Analysis software. Predictive value of candidate genes in the preoperative setting was further validated by qRT-PCR in an independent subset of 60 LABC samples of which 42 had sufficient quality for data analysis, and in postoperative setting using microarray data from 344 node-negative breast cancer patients (Erasmus cohort, GSE2034 and GSE5327) treated either with surgery only (20%) or surgery with RT (80%). RESULTS: We identified 192 significantly differentially expressed genes (FDR < 0.10) between pRT-responsive and non-responsive tumours, related to regulation of cellular development, growth and proliferation, cell cycle control of chromosomal replication, glucose metabolism and NAD biosynthesis II route. APOA1, MAP3K4, and MMP14 genes were differentially expressed (FDR < 0.20) between pRT responders and non-responders in preoperative setting, while MAP3K4 was further validated as RT-specific predictive biomarker of distant metastasis free survival (HR = 2.54, [95%CI:1.42-4.55], p = 0.002) in the postoperative setting. CONCLUSIONS: This study pinpoints MAP3K4 as a putative biomarker of response to RT in both preoperative and postoperative settings and a potential target for radiosensitising combination therapy, warranting further pre-clinical studies and prospective clinical validation.

Tumor response and patient outcome after preoperative radiotherapy in locally advanced non-inflammatory breast cancer patients.

PURPOSE: The purpose of this analysis was to assess the tumor response and long-term outcome in patients treated with preoperative radiotherapy (PRT) without systemic therapy. METHODS: Between 1997 and 2000, 134 patients with non-inflammatory locally advanced breast cancer (LABC) were treated with PRT. The tumor dose was 45 Gy in 15 fractions to the breast and to regional lymph nodes over 6 weeks. Radical mastectomy was performed 6 weeks after PRT to all patients and adjuvant systemic therapy was administered as per protocol. The measures of disease outcome were overall survival (OS) and disease-free survival (DFS) which estimated using the Kaplan-Meier method. RESULTS: Median follow-up was 74 months (range 4-216). Objective clinical tumor response after PRT was observed in 77.6% of the patients. Clinical complete tumor response (cCR) was achieved in 21.6% of the patients. Pathological CR in the breast was achieved in 15% of the patients. The 5- and 10-year OS were 55.1 and 37.8%, respectively. The 5- and 10-year DFS were 39.2 and 27%, respectively. Patients who achieved cCR had significantly longer OS in comparison with patients achieving clinical partial response (cPR) and clinical stable disease (cSD). Similarly, DFS of patients in the cCR group was longer compared with patients with cPR and cSD, yet without statistical significance. CONCLUSIONS: Our results showed that local control in LABC patients achieved by primary PRT, followed by radical mastectomy was comparable with the results reported in the literature. Complete pathologic response to PRT identified a subgroup of patients with a trend toward better DFS and OS.

[Craniospinal radiotherapy in combined therapy of medulloblastoma in children and adolescents]. / Kraniospinalna radioterapija u kombinovanom lecenju meduloblastoma dece i omladine.

PURPOSE: The aim of this study was: 1. to evaluate treatment results of combined therapy (surgery, postoperative craniospinal radiotherapy with or without chemotherapy) and 2. to assess factors affecting prognosis (extend of tumor removal, involvement of the brain stem, extent of disease, postoperative meningitis, shunt placement, age, sex and time interval from surgery to start of postoperative radiotherapy). PATIENTS AND METHODS: During the period 1986-1996, 78 patients with medulloblastoma, aged 1-22 years (median 8.6 years), were treated with combined modality therapy and 72 of them were evaluable for the study endpoints. Entry criteria were histologically proven diagnosis, age under 22 years, and no history of previous malignant disease. The main characteristics of the group are shown in Table 1. Twenty-nine patients (37.2%) have total, 8 (10.3%) near total and 41 (52.5%) partial removal. Seventy-two of 78 patients were treated with curative intent and received postoperative craniospinal irradiation. Radiotherapy started 13-285 days after surgery (median 36 days). Only 13 patients started radiotherapy after 60 days following surgery. Adjuvant chemotherapy was applied in 63 (80.7%) patients. The majority of them (46; 73%) received chemotherapy with CCNU and Vincristine. The survival rates were calculated with the Kaplan-Meier method and the differences in survival were analyzed using the Wilcoxon test and log-rank test. RESULTS: The follow-up period ranged from 1-12 years (median 3 years). Five-year overall survival (OS) was 51% and disease-free survival (DFS) 47% (Graph 1). During follow-up 32 relapses occurred. Patients having no brain stem infiltration had significantly better survival (p = 0.0023) (Graph 2). Patients with positive myelographic findings had significantly poorer survival compared to dose with negative myelographic findings (p = 0.0116). Significantly poorer survival was found in patients with meningitis developing in the postoperative period, with no patient living longer than two years (p = 0.0134) (Graph 3). By analysis of OS and DFS in relation to presence of the malignant cells in liquor, statistically significant difference, i.e. positive CSF cytology was not obtained, which was of statistical importance for survival (p = 0.8207). Neither shunt placement nor shunt type showed any impact on survival (p = 0.5307 and 0.7119, respectively). Children younger than three years had significantly poorer survival compared to those older than 16 years (p = 0.0473). Although there was a better survival rate in females than in males this was not statistically significant (p = 0.2386). The analysis results of treatment showed that significantly better survival occurred in patients in whom total or subtotal tumor removal was possible (p = 0.0022) (Graph 4). Patients who started radiotherapy within two months after surgery have better survival, but again this was not statistically significant, probably due to the small number of patients receiving delayed radiotherapy (p = 0.2231) (Graph 5). CONCLUSION: Based on this factors standard and high risk group could be defined. Combined chemotherapy should to be investigated particularly for high risk subgroup. Future research should be done to define new therapeutic modalities (gene therapy, compounds active in tumor antiangiogenesis etc).