Toxicity Reduction after Craniospinal Irradiation via Helical Tomotherapy in Patients with Medulloblastoma: A Unicentric Retrospective Analysis.

Objectives: Recent trials with craniospinal irradiation (CSI) via helical Tomotherapy (HT) demonstrated encouraging medulloblastoma results. In this study, we assess the toxicity profile of different radiation techniques and estimate survival rates. Materials and Methods: We reviewed the records of 46 patients who underwent irradiation for medulloblastoma between 1999 and 2019 (27 conventional radiotherapy technique (CRT) and 19 HT). Patient, tumor, and treatment characteristics, as well as treatment outcomes-local control rate (LCR), event-free survival (EFS), and overall survival (OS)-were reviewed. Acute and late adverse events (AEs) were evaluated according to the Radiation Therapy Oncology Group and the European Organization for Research and Treatment of Cancer (RTOG/EORTC) criteria. Results: In total, 43 courses of CSI and three local RT were administered to the 46 patients: 30 were male, the median age was 7 years (range 1-56). A median total RT dose of 55 Gy (range 44-68) and a median CSI dose of 35 Gy (range, 23.4-40) was delivered. During follow-up (median, 99 months), six patients (13%) developed recurrence. The EFS rate after 5 years was 84%. The overall OS rates after 5 and 10 years were 95% and 88%, respectively. There were no treatment-related deaths. Following HT, a trend towards lower grade 2/3 acute upper gastrointestinal (p = 0.07) and subacute CNS (p = 0.05) toxicity rates was detected compared to CRT-group. The risk of late CNS toxicities, mainly grade 2/3, was significantly lower following HT technique (p = 0.003). Conclusion: CSI via HT is an efficacious treatment modality in medulloblastoma patients. In all, we detected a reduced rate of several acute, subacute, and chronic toxicities following HT compared to CRT.

The Role of Radiotherapy for Patients With Thyroid Cancer in the Modern Era.

BACKGROUND/AIM: Thyroid cancer (TC) is a relatively rare malignancy. The mainstay treatment is surgery followed by radioactive iodine (RAI) and medical systemic treatments. The role of external beam radiotherapy (EBRT) in TC is controversial regarding the survival benefits. The aim of this study was to analyse the effectiveness of EBRT for different forms of TC in different stages. PATIENTS AND METHODS: Between January 1990 and 2016, 75 patients underwent 255 radiotherapy (RT) courses at our Institution. Local control (LC) and progression-free survival (PFS) were analyzed. RESULTS: The cohort consisted of 22 patients who received curative RT and 53 patients who received RT in a palliative setting. The estimated 5-year LC for the curative group was 92±8% and the palliative group 78±7%. The estimated 5-year PFS for the curative group was 27±9% and for palliative group 31±6%. CONCLUSION: The addition of RT in TC seems to be safe and effective. Our analysis showed an excellent local control (median >15 years) regardless of the treatment setting.

Using Image-guided Intensity-modulated Radiotherapy on Patients With Head and Neck Soft-tissue Sarcoma.

BACKGROUND: Image-guided intensity-modulated radiotherapy (IG-IMRT) is increasingly being used to treat patients with soft-tissue sarcoma (STS) of the head and neck. Although there is no comparison between IMRT and conventional radiation therapy (CRT) concerning their efficacy. In this analysis, we compared CRT and IMRT outcomes for head and neck STS. PATIENTS AND METHODS: Sixty-seven patients who underwent radiotherapy between 1994 and 2017 were identified. RESULTS: The median follow-up was 31 months. Of the 67 patients, 34% were treated with CRT technique and 66% with IG-IMRT. The locoregional relapse rate following IMRT was 21% versus 70% with CRT (p<0.001) and the 5-year locoregional control was 69% versus 28%, respectively (p=0.01). IG-IMRT was associated with non-significant, less acute, and chronic adverse events. In the multivariate analysis, a significant influence of radiation technique on locoregional control was confirmed (p=0.04). CONCLUSION: IG-IMRT seems to be associated both with higher locoregional control as well as lower acute and chronic toxicities.

A treatment planning study comparing tomotherapy, volumetric modulated arc therapy, Sliding Window and proton therapy for low-risk prostate carcinoma.

BACKGROUND: Comparing radiation treatment plans to ascertain the optimal intensity-modulated radiation technique for low-risk prostate cancer. METHODS: Treatment plans for 20 randomly selected patients were generated using the same dose objectives. A dosimetric comparison was performed between various intensity-modulated techniques, including protons. All treatment plans provided conventional treatment with 79.2Gy. Dosimetric indices for the target volume and organs at risk (OAR), including homogeneity index and four conformity indices were analyzed. RESULTS: No statistically significant differences between techniques were observed for homogeneity values. Dose distributions showed significant differences at low-to-medium doses. At doses above 50Gy all techniques revealed a steep dose gradient outside the planning target volume (PTV). Protons demonstrated superior rectum sparing at low-to-higher doses (V10-V70, P < .05) and bladder sparing at low-to-medium doses (V10-V30, P < .05). Helical tomotherapy (HT) provided superior rectum sparing compared to Sliding Window (SW) and Rapid Arc (RA) (V10-V70, P < .05). SW displayed superior bladder sparing compared to HT and RA (V10-V50, P < .05). Protons generated significantly higher femoral heads exposure and HT had superior sparing of those. CONCLUSION: All techniques are able to provide a homogeneous and highly conformal dose distribution. Protons demonstrated superior sparing of the rectum and bladder at a wide dose spectrum. The radiation technique itself as well as treatment planning algorithms result in different OAR sparing between HT, SW and RA, with superior rectum sparing by HT and superior bladder sparing by SW. Radiation plans can be further optimized by individual modification of dose objectives dependent on treatment plan strategy.