Coexistence of intrathyroid thymic carcinoma and papillary thyroid carcinoma: a case report and literature review.

Background: Intrathyroid thymic carcinoma (ITTC) is a rare neoplasm of the thyroid, which accounts for less than 0.15% of all thyroid malignancies. The coexistence of ITTC and papillary thyroid carcinoma (PTC) is an extremely rare condition reported only in a limited number of cases. Case summary: A 26-year-old female presented with a growing neck mass, hoarseness, and dysphagia over four months. Ultrasonography revealed that the entire left lobe and the isthmus of the thyroid were replaced with a hypoechoic mass. Moreover, it revealed two hypoechoic nodules in the right thyroid. The patient underwent a total thyroidectomy and paratracheal lymph node dissection. Histopathological examinations revealed the coexistence of ITTC and PTC in the same thyroid. In immunohistochemical analyses, the ITTC was positive for CD5, P63, CD117, and CK 5/6 and negative for thyroglobulin, calcitonin, and TTF 1. At the same time, PTC was positive for TTF 1 and thyroglobulin and negative for CD5, P63, and CK 5/6. The patient received postoperative radiotherapy and remained well with no evidence of recurrence during one month follow-up. Conclusion: Distinguishing ITTC from other thyroid malignancies before the surgery is challenging due to its non-specific presentations. Therefore, the diagnosis relies on postoperative studies, especially immunohistochemistry. The recommended treatment approach to improve survival in ITTC cases is total thyroidectomy combined with cervical lymph node dissection, followed by postoperative radiotherapy. The coexistence of ITTC and PTC may indicate the similarity in the underlying mechanisms of these tumors. However, further investigations are needed to understand this potential correlation.

Estimating the Dose-Response Relationship for Ocular Pain after Radiotherapy of Head and Neck Cancers and Skull Base Tumors based on the LKB Radiobiological Model.

Background: Radiotherapy is considered a compromise between the amount of killed tumor cells and the damage caused to the healthy tissue. Regarding this, radiobiological modeling is performed to individualize and optimize treatment strategies. Objective: This study aimed to determine the normal tissue complication probability (NTCP) of acute ocular pain following radiotherapy. Material and Methods: In this prospective observational study, the clinical data were collected from 45 patients with head and neck cancers and skull-base tumors, and dosimetric data were recorded after contouring the eye globe. Acute ocular pain was prospectively assessed with a three-month follow-up. The Lyman-Kutcher-Berman (LKB) parameters were estimated using the Area Under Curve (AUC) of Receiver Operating Characteristic (ROC) maximization and Maximum Likelihood (MLH) methods, and the NTCP of acute ocular pain was then determined using generalized LKB radiobiological model. The model performance was evaluated with AUC, Brier score, and Hosmer-Lemeshow tests. Results: Six out of 45 (13.33%) patients developed acute ocular pain (grade 1 or more). LKB model showed a weak dose-volume effect (n=0.09), tolerance dose for a 50% complication (TD50) of 27.54 Gy, and slope parameter (m) of 0.38. The LKB model showed high prediction performance. The LKB model predicted that NTCP would be less than 25% if the generalized equivalent uniform dose (gEUD) was kept below 20 Gy. Conclusion: The LKB model showed a high performance in determining the NTCP of ocular pain so that the probability of ocular pain will be less than 25% if the eye globe mean dose is kept below 12 Gy.

Out-of-Field Dose Measurement by TLD Dosimetry and Estimation of Radiation-Induced Secondary Cancer Risk of Thyroid and Breast from Head Radiotherapy.

Background: Radiation therapy, the most common form of cancer treatment, can result in late complications, such as secondary breast and thyroid cancers. Objective: This study aimed to evaluate the risk of secondary cancers using two radiobiological models of Excess Absolute Risk (EAR) and Excess Relative Risk (ERR) in patients with brain cancer undergoing radiotherapy for improved survival rates of cancer patients. Material and Methods: In this expository cross-sectional study, 45 patients under the age of 40 years underwent Whole Brain Radiotherapy (WBRT) using a compact accelerator in Shahid Ramezanzadeh Hospital, Yazd, Iran. Out-of-field organ dose measurement was performed using a Thermoluminescent Dosimeter (TLD) to determine the dose to thyroid and breast tissues. The risk of secondary cancers in these organs was calculated 3, 5, 10, 15, and 20 years after radiation therapy. Results: The mean values of thyroid cancer risk in men and women were 0.418±0.509 and 0.274±0.306, respectively. ERR values of breast cancer in 3-, 5-, 10-, 15-, and 20-year women undergoing radiation therapy were 1.084±2.938, 0.594±1.407, 0.248±0.497, 0.138±0.248, and 0.091±0.148, respectively. EAR values of breast cancer in 3-, 5-, 10-, 15-, and 20-year women following radiation therapy were 0.064±0.060, 0.077±0.071, 0.119±0.100, 0.178±0.248, and 0.259±0.178, respectively. Conclusion: After irradiation, the risk of secondary cancer is affected by factors, such as the patient's age and gender. The secondary thyroid cancer is higher than that of other organs, such as the breast, in the patients undergoing WBRT.

Determination and comparison of dosimetric parameters of three-dimensional conformal radiotherapy, field in field, and intensity-modulated radiotherapy techniques in radiotherapy of breast conserving patients.

Purpose: Three radiation therapy techniques for breast are common, namely three-dimensional conformal radiotherapy (3D-CRT), Field-in-Field (FIF), and Intensity-Modulated Radiotherapy (IMRT). The purpose of this study was to determine and compare dosimetric parameters of three different treatment planning planning types; 3D-CRT, FIF, and IMRT in target and normal tissues after breast-conserving surgery. Methods: One hundred patients with left or right breast cancer cooperated in this study. They were divided into three categories (small, medium, and large size) based on breast volume. Three treatment planning techniques were carried out by planner for each patient in Prowess® 5.2 Treatment Planning System. The dosimetric parameters were obtained from dose-volume histograms using the CERR software (MATLAB Company, Washington, USA), which runs as an add-on in MATLAB software. Results: 3D-CRT technique with the highest value of Dmax creates more hot spots than the other techniques in the tumor region (P = 0.013). IMRT and FIF showed the best uniformity compared to 3D-CRT in all groups with respect to the values of the parameters D98 and D2. IMRT provided the best coverage in the tumor compared to other methods (P < 0.001). 3D-CRT technique yielded a high volume receiving ≥107% of the prescription dose (P < 0.001). Among the three methods, the FIF method results in a lower dose to the lung for treatment based on the V5 and V20 parameters (P < 0.001). Homogeneity index for IMRT was better than FIF, as well as, conformity index (CI) for IMRT and FIF was better than 3D-CRT. Conclusion: IMRT and FIF plans offered excellent target coverage and uniformity, whereas FIF had better protection of healthy tissues. Thus FIF method is an efficient method to improve the quality of treatment for breast cancer patients.

Comparing Early-Stage Breast Cancer Patients with Sentinel Lymph Node Metastasis with and without Completion Axillary Lymph Node Dissection: A Systematic Review and Meta-Analysis.

BACKGROUND: Currently, the standard method for staging and treatment of axillary lymph nodes for early-stage breast cancer is sentinel lymph node biopsy (SLNB), while axillary lymph node dissection (ALND) is used in cases with palpable axillary lymph nodes or positive SLNB cases. The aim of this review was to compare overall survival (OS), disease-free survival (DFS), and axillary recurrence in early-stage breast cancer patients underwent SLNB or SLNB and completion ALND. METHODS: The databases of PubMed, Scopus, and Cochrane Library were searched using the key words of "breast cancer", "axillary lymph node dissection", and "sentinel lymph node dissection". In addition, other sources were searched for ongoing studies (i.e., clinicaltrials.gov). The clinical trials were evaluated based on the Jadad quality criteria, and cohort studies were evaluated according to the STROBE criteria. At the end of the search, the articles were screened independently by two reviewers to check their eligibility to be included in the study. Afterwards, the data were extracted independently by two researchers. RESULTS: After searching the databases, 169 papers were retrieved. However, after removing the duplicates and studying the titles and abstracts of these papers, only ten ones underwent further investigation. After reading full-text of each article, four studies were finalized. Following a manual search, 27 papers were entered into the study for the final evaluation, 11 of which were included in the meta-analysis based on the inclusion and exclusion criteria. The findings showed no significant differences in OS, DFS, and axillary recurrence in early-stage breast cancer patients underwent SLNB or SLNB and completion ALND. CONCLUSION: The findings did not confirm that ALND improved OS, DFS, and axillary recurrence in patients who were clinically node-negative and positive SLNB.

Review on the Oncology Practice in the Midst of COVID-19 Crisis: The Challenges and Solutions.

As of late 2019, the outbreak of novel coronavirus disease (COVID-19) -that started in China- has rapidly afflicted all over the world. The COVID-19 pandemic has challenged health-care facilities to provide optimal care. In this context, cancer care requires special attention because of its peculiar status by including patients who are commonly immunocompromised and treatments that are often highly toxic. In this review article, we have classified the main impacts of the COVID-19 pandemic on oncology practices -followed by their solutions- into ten categories, including impacts on (1) health care providers, (2) medical equipment, (3) access to medications, (4) treatment approaches, (5) patients' referral, (6) patients' accommodation, (7) patients' psychological health, (8) cancer research, (9) tumor board meetings, and (10) economic income of cancer centers. The effective identification and management of all these challenges will improve the standards of cancer care over the viral pandemic and can be a practical paradigm for possible future crises.
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