Comparison of Doses to Parotid, Temporomandibular Joint, and Pharyngeal Constrictor Muscles Using Different Techniques in Radiotherapy for Oropharyngeal Cancer.

OBJECTIVE: The purpose of this research was to compare two treatment techniques for oropharyngeal cancers: conventional linac-based static intensity-modulated radiotherapy (sIMRT) and helical tomotherapy (HT). The study examined several parameters, including target coverage, organs at risk, integral dose, and beam on time. Additionally, the study evaluated the doses to the parotid, temporomandibular joint, and pharyngeal constrictor muscles, which are important for swallowing. METHOD: The present study retrospectively analyzed the data of 13 patients with oropharyngeal cancer who underwent radiotherapy between 2019 and 2021. The treatment plans for each patient were regenerated using both sIMRT and HT treatment planning systems with the sequential boost method. The techniques were evaluated and compared based on dose-volume histogram, homogeneity index, and conformity index parameters. The target coverage and organs at risk were statistically compared for two techniques. Additionally, the doses received by the healthy tissue volume were obtained for integral dose evaluation. The beam on time for each technique was assessed. RESULTS: When considering planning target volume evaluation, there was no difference in Dmeans between the two techniques and sIMRT demonstrated higher D2% values compared to the HT. The HT technique had better results for all organs at risk, such as the parotid, temporomandibular joint, and pharyngeal constrictor muscle. As for integral dose, it has been shown that the sIMRT technique provides better protection compared to HT. In addition, the beam on time was also longer with the HT technique. CONCLUSION: Both techniques may provide optimal target coverage for patients with oropharyngeal cancer. HT conferred notable advantages, especially with regard to critical structures implicated in swallowing, such as the parotid, temporomandibular joint, and pharyngeal constrictor muscle, in comparison to sIMRT.

Challenging treatment of parameningeal rhabdomyosarcoma with leptomeningeal metastasis: Case report and review of literature.

Parameningeal rhabdomyosarcomas (PM RMSs) are rarely seen childhood tumors. Their treatment might be challenging and prognosis is poor compared to other head and neck RMS. Here we report a PM RMS presenting with leptomeningeal seeding metastasis a year after diagnosis. A five-year-old girl presented with an enlarging mass protruding from the right ear and right facial paralysis. Magnetic resonance imaging (MRI) revealed a large mass extending from right external auditory canal to the temporal lobe, pterygoid fossa and nasopharynx with an intracranial component indenting the right temporal lobe and extending into the right cavernous sinus. Trucut biopsy revealed embryonal rhabdomyosarcoma. Cerebrospinal fluid (CSF) cytology was negative for malignant cells. Chemotherapy was started since it was found unresectable. At second week of chemotherapy, radiotherapy was applied to primary tumor location with intensity-modulated radiation therapy (IMRT) technique in 1.8 Gy fractions to total dose of 50.4 Gy. At week 27, MRI showed significant response. At week 36, the patient presented with vomiting and tendency to sleep. MRI was found to be compatible with meningitis and antibacterial therapy was started. At week 39, chemotherapy was stopped. But MRI performed one month later revealed linear contrast enhancements around the spinal cord compatible with leptomeningeal metastases. Chemotherapy and craniospinal irradiation were applied. But the patient did not improve and received palliative treatment. Six months after the completion of radiotherapy the patient died. Treatment of parameningeal rhabdomyosarcomas require multidisciplinary approach including surgery, radiotherapy, and chemotherapy. Prognosis is poor for patients with leptomeningeal spread.

Radiotherapy for vertebral hemangioma: the single-center experience of 80 patients.

PURPOSE: This study aimed to evaluate the therapeutic effect of radiotherapy and to determine possible prognostic factors in patients with painful vertebral hemangioma. METHODS: In the last two decades, 80 patients with vertebral hemangioma who received radiotherapy in our institute were evaluated in terms of pain response, treatment-related side effects, and prognostic factors. All patients were questioned 3 months after radiotherapy for the evaluation of pain response and were divided into three groups (complete response, partial response, and no change). Moreover, the visual analog scale (VAS) was used for pain response assessment in 46 patients. Pain status was assessed to detect recurrence at each clinical examination during the follow-up period. Possible prognostic factors such as gender, size of the hemangioma, location, multilevel involvement and additional musculoskeletal disease on pain response were analyzed. RESULTS: In this study, 45 individuals had lesions in the lumbar spine, 28 in the thoracic, and 7 in the cervical region. Furthermore, 51 patients had additional musculoskeletal conditions such as disc herniation, degenerative diseases, spondylolisthesis, and compression fracture. Radiotherapy was performed with a median daily dose of 2 Gy and a median total dose of 40 Gy. Complete pain response occurred in 58.8% of patients, 26.2% of patients had partial pain response, and 15% of patients had no pain response. The overall response rate was 85%, and 7 patients showed recurrent pain symptoms in the overall response group at routine follow-up. Additional musculoskeletal disorders were found to be the only prognostic factor associated with pain response. The median follow-up time was 60 months. Secondary malignancy was not found in any of the patients in this short follow-up time. No acute or late radiation-associated side effects greater than grade II were observed. CONCLUSION: To our best knowledge, this study is one of the largest single-institution radiotherapy series on vertebral hemangiomas reported to date. The obtained data support the efficacy and safety of radiotherapy in the treatment of painful vertebral hemangioma. Our study showed that additional musculoskeletal disease plays an important role in pain response. Other prognostic factors and treatment of vertebral hemangioma with stereotactic radiosurgery should be investigated in future studies.