Volume changes during head-and-neck radiotherapy and its impact on the parotid dose - A single-institution observational study.

AIMS: This study aims at assessing the volume changes that occur in the targets (gross tumor volume and planning target volume [PTV]) and the organs at risk in squamous cell carcinoma of the head and neck during radiotherapy and assessing the dose changes that occur as a result of them. SETTINGS AND DESIGN: This was a prospective observational study in a tertiary care center after obtaining the appropriate scientific and ethics committee clearance. SUBJECTS AND METHODS: Forty-five patients diagnosed with squamous cell carcinoma of the head and neck, who were treated with intensity-modulated radiotherapy in the time period from March 2018 to May 2019, were enrolled in the study. A planning computed tomography (CT) scan (CTplan) was done for all patients, followed by scans after 15 fractions (CT15) and after 25 fractions (CT25). The volume changes and the subsequent dose changes were assessed and recorded. STATISTICAL ANALYSIS USED: Data entry was done in MS Excel spreadsheet. The continuous variables were expressed as mean + standard deviation. The comparison of normally distributed continuous variables was done by paired t-test. Data analysis was done by SPSS (Statistical Package for the Social Sciences) version 16.0. P < 0.05 was considered statistically significant. A multivariate linear regression model was constructed to study the correlation between mean dose to the parotid glands and the other variables. All statistical modeling and analysis were done using SAS (Statistical Analysis Software) version 9.4. RESULTS: Of the 45 patients, 25 were male and 20 were female. The majority of the patients had malignancies in the oral cavity (16) and hypopharynx (14). Most of them had Stage III/IV (AJCC v 8) disease (41). There were a 36% decrease in the PTV-high risk (PTV-HR) volume and a 6.05% decrease in the PTV-intermediate risk (PTV-IR) volume CT15. In CT25, the volume decrease in the PTV-HR and the PTV-IR was 47% and 9.06%, respectively. The parotid glands also underwent a reduction in their volume which has been quantified as 21.7% and 20.9% in the ipsilateral and contralateral parotids in CT15 and 36% and 33.6% in CT25, respectively. The D2 (dose received by 2% of the volume) and D98 (dose received by 98% of the volume) of the PTV-IR showed changes of +3.5% and -0.2% in CT15 and + 4.6% and -0.31% in CT25, respectively. The homogeneity index and conformity number of the PTV-IR changes by 0.03 and 0.08 in CT15 and by 0.04 and 0.12 in CT25, respectively. The mean dose to the ipsilateral parotid gland increased by 14% in CT15 and 19% in CT25. The mean dose to the contralateral parotid gland increased by 17% in CT15 and 25% in CT25. CONCLUSION: The dose to the parotid glands increases as a result of the changes that occur during the course of radiation. The changes are significant after 15 fractions of radiation. A replanning at this juncture might be considered to reduce the dose to the parotid glands.

Long-term outcome of high-dose-rate brachytherapy and perioperative brachytherapy in early mobile tongue cancer.

PURPOSE: To evaluate long-term outcome of high-dose-rate brachytherapy and perioperative brachytherapy in early mobile tongue cancer. MATERIAL AND METHODS: Seventy-three patients with clinically staged T1/T2 N0 M0 of mobile tongue cancer were studied retrospectively. Between January 2000 and September 2010, 47 patients underwent high-dose-rate brachytherapy (HDR-BT) alone and 26 patients underwent perioperative brachytherapy (PB). Endpoints were overall survival, disease-free survival, loco-regional control, and late side effects. RESULTS: Median age was 52 years and median follow-up was 74 months (range, 60-180). There were no local recurrences in the PB group. Overall survival at 6 years was 74.7% vs. 92.3% in HBR BT and PB group, respectively (p = 0.032). Disease-free survival at 6 years was 55.3% vs. 92.3% respectively in HDR-BT and PB (p = 0.002). Disease-free survival at 6 years in tumor histologic grade 1/2 patients was 76.3 months versus 40% in grade 3 patients. Nodal recurrence-free rate at 6 years was 67.5% with HDR-BT only, and 96.2% with PB (p = 0.007). In HDR BT only group, nodal recurrence-free rate at 6 years in T1 patients was 89.8% versus 29.4% in T2 patients. 16% and 7% patients developed soft tissue necrosis and osteoradionecrosis, respectively. Multivariate Cox proportional hazards analysis revealed significant correlation of local recurrence with tumor grade (p = 0.029), nodal recurrence with T-stage (p = 0.007), and disease-free survival with age (p = 0.003) and T stage (p = 0.026). CONCLUSIONS: HDR-BT alone gives acceptable loco-regional control in T1 tumors. T2 stage tumors should not be treated by brachytherapy alone in view of high failure rates in nodal regions and should undergo either neck dissection or nodal irradiation. Perioperative brachytherapy is investigational and can be considered in patients who are at high-risk for local recurrence in patients undergoing surgery alone.

Technical considerations in brachytherapy boost for a case of squamous cell carcinoma of the external auditory canal based on our case.

Squamous cell carcinoma of the external auditory canal is a rare entity. The patients present with ear discharge and otalgia. They are treated with radiotherapy and surgery. Surgery with oncological priorities is quite complex with substantial consequences. We are reporting a patient with squamous cell carcinoma of the external auditory canal, who was treated with limited surgery followed by radiotherapy. Radiotherapy was a combination of external beam radiotherapy and brachytherapy. High dose rate brachytherapy was given using an ear speculum fixed with wax and a suction catheter. This article is to highlight the technique and dosimetry of the brachytherapy procedure.

Regaining vision from no perception of light after radiotherapy for a case of suprasellar meningioma.

Meningiomas are tumours of the arachnoid cap cells. Usually they are referred to according to their location. They are primarily treated with surgery. They tend to recur following surgery. Suprasellar meningiomas frequently present with visual disturbances. Our patient is a case of recurrent suprasellar meningioma. The visual acuity in one eye was No Perception of Light(NPL). From NPL, the visual acuity improved to 6/12 in six months after High Precision Irradiation (HPI). This case emphasizes the importance and the need for aggressive management. It also shows the use of radiotherapy techniques used in synergy to produce the necessary results.