Re-irradiation with stereotactic radiotherapy for recurrent high grade glial tumors

Background: Despite the radical treatments applied, recurrence is encountered in the majority of high-grade gliomas (HGG). There is no standard treatment when recurrence is detected, but stereotactic radiotherapy (SRT) is a preferable alternative. The aim of this retrospective study is to evaluate the efficacy of SRT for recurrent HGG, and to investigate the factors that affect survival. Materials and methods: From 2013 to 2021, a total of 59 patients with 64 lesions were re-irradiated in a single center with the CyberKnife Robotic Radiosurgery System. The primary endpoints of the study were overall survival (OS), progression free survival (PFS) and local control rates (LCR). Results: The median time to first recurrence was 13 (4–85) months. SRT was performed as a median prescription dose of 30 Gy (range 15–30), with a median of 5 fractions (1–5). The median follow-up time was 4 months (range 1–57). The median OS was 8 (95% CI: 4.66-11.33) months. Age, grade 3, tumor size were associated with better survival. The median PFS was 5 [95% confidence interval (CI): 3.39–6.60] months. Age, grade 3 and time to recurrence > 9 months were associated with improved PFS. Grade 3 gliomas (p = 0.027), size of tumor < 2 cm (p = 0.008) remained independent prognostic factors for OS in multivariate analysis. Conclusion: SRT is a viable treatment modality with significant survival contribution. Since it may have a favorable prognostic effect on survival in patients with tumor size < 2 cm, we recommend early diagnosis of recurrence and a decision to re-irradiate a smaller tumor during follow-up.

Stereotactic radiotherapy in acoustic neuroma cases: Tumor control and clinical results

Since acoustic neuromas (AN) are slow-growing tumors, they frequently reduce patients' quality of life by compressing adjacent nerves. After evaluating various factors, the most appropriate treatment for the patient is preferred among follow-up, surgery, or radiotherapy. Surgery and radiotherapy have been shown to have comparable results in AN. Stereotactic radiotherapy (SRT) has long emerged as a viable option for treating intracranial tumors. Thus, it was aimed to determine the local control rate (LCR), and treatment failure and to evaluate the hearing level and facial nerve symptoms in AN treated with SRT. Forty-five patients were treated consecutively with CyberKnife-SRT between January 2014 and December 2021. Tumors were anatomically classified according to Koos grade; patients presenting with hearing impairment were graded according to the Gardner-Robertson (GR) scale and patients' expressions. Loss of function in the facial nerve was also evaluated according to the House-Brackman scale. SRT was applied to 24 patients with 12 Gy/1 fx, 18 with 18 Gy/3 fx, and 3 with 25 Gy/5 fx. At a median follow-up of 24 months (2-73), progression was detected in 4 (8.9%) patients. None required additional intervention, and no treatment failure was observed (0%). Tumor control was achieved in 91.1% of the patients; 2-y and 5-y LCR were 91.2% and 79.8%. It was observed that 3 (30%) out of 10 patients who had serviceable hearing according to the GR scale at the beginning were non-serviceable hearing during the follow-up. Transient facial paralysis was observed in 3 (6.7%) patients. No statistically significant factor could be detected in LCR, hearing, and facial nerve preservation. Our findings are similar to previous SRT data regarding LCR, treatment failure, hearing preservation, and facial nerve impairment. SRT is an effective treatment method for AN with reasonable results. [Med-Science 2023; 12(3.000): 933-40

Retrospective feasibility study of simultaneous integrated boost in cervical cancer using Tomotherapy: the impact of organ motion and tumor regression.

BACKGROUND: Whole pelvis intensity modulated radiotherapy (IMRT) is increasingly being used to treat cervical cancer aiming to reduce side effects. Encouraged by this, some groups have proposed the use of simultaneous integrated boost (SIB) to target the tumor, either to get a higher tumoricidal effect or to replace brachytherapy. Nevertheless, physiological organ movement and rapid tumor regression throughout treatment might substantially reduce any benefit of this approach. PURPOSE: To evaluate the clinical target volume - simultaneous integrated boost (CTV-SIB) regression and motion during chemo-radiotherapy (CRT) for cervical cancer, and to monitor treatment progress dosimetrically and volumetrically to ensure treatment goals are met. METHODS AND MATERIALS: Ten patients treated with standard doses of CRT and brachytherapy were retrospectively re-planned using a helical Tomotherapy - SIB technique for the hypothetical scenario of this feasibility study. Target and organs at risk (OAR) were contoured on deformable fused planning-computed tomography and megavoltage computed tomography images. The CTV-SIB volume regression was determined. The center of mass (CM) was used to evaluate the degree of motion. The Dice's similarity coefficient (DSC) was used to assess the spatial overlap of CTV-SIBs between scans. A cumulative dose-volume histogram modeled estimated delivered doses. RESULTS: The CTV-SIB relative reduction was between 31 and 70%. The mean maximum CM change was 12.5, 9, and 3 mm in the superior-inferior, antero-posterior, and right-left dimensions, respectively. The CTV-SIB-DSC approached 1 in the first week of treatment, indicating almost perfect overlap. CTV-SIB-DSC regressed linearly during therapy, and by the end of treatment was 0.5, indicating 50% discordance. Two patients received less than 95% of the prescribed dose. Much higher doses to the OAR were observed. A multiple regression analysis showed a significant interaction between CTV-SIB reduction and OAR dose increase. CONCLUSIONS: The CTV-SIB had important regression and motion during CRT, receiving lower therapeutic doses than expected. The OAR had unpredictable shifts and received higher doses. The use of SIB without frequent adaptation of the treatment plan exposes cervical cancer patients to an unpredictable risk of under-dosing the target and/or overdosing adjacent critical structures. In that scenario, brachytherapy continues to be the gold standard approach

A multicenter retrospective analysis of patients with nasopharyngeal carcinoma treated in IMRT era from a nonendemic population: Turkish Society for Radiation Oncology Head and Neck Cancer Group Study (TROD 01-001).

Background: We aimed to evaluate patients with nasopharyngeal carcinoma (NPC) in a nonendemic population. Methods: In a national, retrospective, multicenteric study, 563 patients treated with intensity modulated radiotherapy at 22 centers between 2015 and 2020 were analyzed. Results: Median age was 48 (9–83), age distribution was bimodal, 74.1% were male, and 78.7% were stage III-IVA. Keratinizing and undifferentiated carcinoma rates were 3.9% and 81.2%. Patients were treated with concomitant chemoradiotherapy (48.9%), or radiotherapy combined with induction chemotherapy (25%) or adjuvant chemotherapy (19.5%). After 34 (6–78) months follow-up, 8.2% locoregional and 8% distant relapse were observed. Three-year overall survival was 89.5% and was lower in patients with age ≥50, male sex, keratinizing histology, T4, N3 and advanced stage (III-IVA). Conclusions: Patients with NPC in Turkey have mixed clinical features of both east and west. Survival outcomes are comparable to other reported series; however, the rate of distant metastases seems to be lower