Assessment of Thyroid Lobe Dose in Breast Cancer Intraoperative Radiotherapy

Background:

Breast cancer is the most common cancer among women. Considering the fact that a high dose is delivered in a single fraction of IORT, the evaluation of the dose at sensitive organs like thyroid is necessary.

Objective:

The current study has aimed to evaluate the received dose to thyroid lobes in the breast IORT technique.

Material and Methods:

A total of 49 women with breast cancer undergoing IORT were enrolled in this cross-sectional study with census sampling. Immediately after tumor resection, a single dose of 20 Gray at the applicator surface was delivered using 50KV X-ray by an Intrabeam machine. The thyroid dose was detected using thermoluminescent detectors (TLD) 100 at the mid-thyroid line, left and right lobes.

Results:

The dose at the right and left lobes of the thyroid gland as well as the mid-thyroid line was found to be 40.18±35.44 mGy, 35.50±27.32 mGy, and 40.61±32.47 mGy, respectively. The right lobe received a significantly higher absorbed dose compared to the left lobe when the right breast was under IORT treatment. The same trend was seen with the left lobe and left breast under IORT treatment (P=0.0001 and P=0.018, respectively). The applicator size showed non-significant effects on the absorbed dose at the thyroid gland. Also, the applicator depth had a non-significant inverse effect on thyroid dose.

Conclusion:

According to our findings, the absorbed dose at each thyroid lobe depends on the under-treatment side as well as the applicator size and depth (applicator upper surface distance from the skin).

EGFR Expression in Patients with Esophageal Squamous Cell Carcinoma and its Association with Pathologic Response to Preoperative Chemoradiotherapy: A Study in Northeastern Iran

INTRODUCTION

Esophageal squamous cell carcinoma (ESCC) accounts for 80% of all esophageal cancers worldwide. It is the most common histological type of esophageal carcinoma in low-resource countries. ESCC is prevalent in Asian countries, accounting for more than 95% of esophageal cancers. The epidermal growth factor receptor (EGFR) is involved in cancer development, as its gene is often mutated and/or amplified in cancer cells. According to recent statistics, esophageal cancer is the eighth most common cancer in Iran.

METHODS

In this retrospective study, we assessed EGFR overexpression, using immunohistochemistry (IHC) in 68 patients with ESCC, undergoing neoadjuvant chemoradiotherapy and esophagectomy in 2011-2014. The treatment protocol included external beam radiotherapy (40 Gy), concomitant with cisplatin 20mg/m2 and 5- fluorouracil (5-FU) 1000 mg/m2 for 4 consecutive days during the first and fourth weeks of treatment. To compare the two groups (EGFR positive and negative) in terms of complete pathologic response, Chi-square test was performed using SPSS version 16.

RESULTS

The median age of the patients was 59 years (range: 27-70 years), with a female-to-male ratio of 1.06. Overall, 70% of the subjects showed EGFR overexpression. Complete pathologic response to neoadjuvant treatment was significantly higher in EGFR-positive patients (40% vs. 15.8%, P = 0.05). In all cases, 1- and 3-year overall survival rates were 86.6% ± 4.1 and 48% ± 6.9, respectively. The 1- and 3-year disease free survival rates were calculated as 71.8% ± 5.4 and 44.3% ± 6.5, respectively. The overall survival rate was relatively higher in cases with EGFR overexpression, although the difference was not statistically significant (5-year survival rate: 47.9 ± 8.2 vs. 30.9 ± 13, P = 0.23).

CONCLUSION

EGFR overexpression was reported in the majority of patients with ESCC in northeastern Iran. Moreover, EGFR overexpression was significantly associated with complete pathologic response.

Abstract 4752: Induction of cytotoxic T lymphocytes primed with tumor RNA-loaded dendritic cells in esophageal squamous cell carcinoma: Preliminary step for DC vaccine design

Backgrounds: Dendritic Cells (DC) are potent antigen presenting cells with the ability to prime naïve T cells and convert them to cytotoxic CTL. We evaluated the capability of autologous DCs transfected with total Tumor and normal RNA to induce cytotoxic CTL as the preliminary step to design DC-based vaccine in the esophageal squamous cell carcinoma (ESCC).

Methods: Monocytes-derived DCs were electroporated with either total tumor RNA or normal RNA. T cells were then primed with tumor RNA transfected DCs and lysing effects of the generated CTL were measured with Cytotoxicity assay and IFN-γ Release Elispot Assay.

Results: Cytotoxicity against DCs loaded with tumoral RNA was induced (%24.8±5.2 SEM) while in normal RNA-loaded DCs it was minimal (%6.1±2.4 SEM) and significantly lower (p < 0.05). INF-γ secretion was more than 2-folds higher in tumoral RNA-loaded DCs when compared with normal RNA-loaded DCs (p < 0.05).

Conclusion: Electroporating DCs with tumor RNA made tumor antigen presenting cells that enhanced cytotoxicity effects of T cells against ESCC. This may be a useful autologous ex vivo screening tool for confirming the lytic effects of primed T cells on tumor and evaluate probable further adverse effects on noncancerous tissue. These data are a crucial preliminary step to establish a total tumor RNA-pulsed DC vaccine therapy of ESCC.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4752.