Low-Dose Computed Tomography Scanning Protocols for Online Adaptive Proton Therapy of Head-and-Neck Cancers

PURPOSE

To evaluate the suitability of low-dose CT protocols for online plan adaptation of head-and-neck patients.

METHODS

We acquired CT scans of a head phantom with protocols corresponding to CT dose index volume CTDI_vol in the range of 4.2-165.9 mGy. The highest value corresponds to the standard protocol used for CT simulations of 10 head-and-neck patients included in the study. The minimum value corresponds to the lowest achievable tube current of the GE Discovery RT scanner used for the study. For each patient and each low-dose protocol, the noise relative to the standard protocol, derived from phantom images, was applied to a virtual CT (vCT). The vCT was obtained from a daily CBCT scan corresponding to the fraction with the largest anatomical changes. We ran an established adaptive workflow twice for each low-dose protocol using a high-quality daily vCT and the corresponding low-dose synthetic vCT. For a relative comparison of the adaptation efficacy, two adapted plans were recalculated in the high-quality vCT and evaluated with the contours obtained through deformable registration of the planning CT. We also evaluated the accuracy of dose calculation in low-dose CT volumes using the standard CT protocol as reference.

RESULTS

The maximum differences in D₉₈ between low-dose protocols and the standard protocol for the high-risk and low-risk CTV were found to be 0.6% and 0.3%, respectively. The difference in OAR sparing was up to 3%. The Dice similarity coefficient between propagated contours obtained with low-dose and standard protocols was above 0.982. The mean 2%/2 mm gamma pass rate for the lowest-dose image, using the standard protocol as reference, was found to be 99.99%.

CONCLUSION

The differences between low-dose protocols and the standard scanning protocol were marginal. Thus, low-dose CT protocols are suitable for online adaptive proton therapy of head-and-neck cancers. As such, considering scanning protocols used in our clinic, the imaging dose associated with online adaption of head-and-neck cancers treated with protons can be reduced by a factor of 40.

CT-on-Rails Versus In-Room CBCT for Online Daily Adaptive Proton Therapy of Head-and-Neck Cancers

PURPOSE

To compare the efficacy of CT-on-rails versus in-room CBCT for daily adaptive proton therapy.

METHODS

We analyzed a cohort of ten head-and-neck patients with daily CBCT and corresponding virtual CT images. The necessity of moving the patient after a CT scan is the most significant difference in the adaptation workflow, leading to an increased treatment execution uncertainty σ. It is a combination of the isocenter-matching σ_i and random patient movements induced by the couch motion σ_m. The former is assumed to never exceed 1 mm. For the latter, we studied three different scenarios with σ_m = 1, 2, and 3 mm. Accordingly, to mimic the adaptation workflow with CT-on-rails, we introduced random offsets after Monte-Carlo-based adaptation but before delivery of the adapted plan.

RESULTS

There were no significant differences in accumulated dose-volume histograms and dose distributions for σ_m = 1 and 2 mm. Offsets with σ_m = 3 mm resulted in underdosage to CTV and hot spots of considerable volume.

CONCLUSION

Since σ_m typically does not exceed 2 mm for in-room CT, there is no clinically significant dosimetric difference between the two modalities for online adaptive therapy of head-and-neck patients. Therefore, in-room CT-on-rails can be considered a good alternative to CBCT for adaptive proton therapy.

The Benefit of Zinc Sulfate in Oropharyngeal Mucositis during Hyperfractionated Accelerated Concomitant Boost Radiotherapy with Concurrent Cisplatin for Advanced-Stage Oropharyngeal and Hypopharyngeal Cancers

Background:

Radiation-induced oropharyngeal mucositis is a major problem causing widespread clinical symptoms and may interfere with treatment plans, ultimately jeopardizing patient outcome. Zinc supplementation may be considered beneficial in preventing acute toxicity during chemoradiation.

Aims and Objective:

The aim of the study is to determine the effect of zinc supplementation on radiation-induced oropharyngeal mucositis in Stage III and IV-A oropharynx and hypopharynx cancers treated by hyperfractionated accelerated concomitant boost radiotherapy with weakly cisplatin. The objective behind the study is to know any changes in the onset, duration, and severity of oropharyngeal mucositis by implementation of oral zinc sulfate.

Materials and Methods:

The study is double-blinded randomized controlled assessment involving 120 patients (60 – control and 60 – experimental) treated with chemoradiation for oropharyngeal and hypopharyngeal cancers. The experimental group received oral zinc sulfate 150 mg once daily during and after treatment, whereas the control group patients were given placebo. The categorical data were analyzed using the Chi-square test and Pearson correlation. The Friedman test was used for comparison of oral mucositis grading between the groups.

Results:

A statistically significant difference was found in the zinc-supported experimental group showing delay in onset, decrease in severity, and duration of oropharyngeal mucositis.

Conclusion:

Zinc supplementation could be beneficial in managing oropharyngeal mucositis during chemoradiation of head-and-neck cancers with no untoward side effects.

Head and neck squamous cell carcinoma in HIV, HBV and HCV seropositive patients - Prognosis and its predictors

Introduction

Patients receiving treatment for head-and-neck squamous cell carcinoma (HNSCC) also may have coexisting viral infections caused by HIV, HBV, and HCV (seropositive). There is scarce literature regarding the clinical presentation and treatment outcomes for these patients with coexisting viral infections (seropositive HNSCC). We conducted this study to assess the clinical presentation and treatment outcomes (overall survival [OS] and disease-specific survival [DSS]) of seropositive HNSCC patients.

Methodology

This was a retrospective cohort study on seropositive HNSCC patients registered at our center from 2012 to 2014. The viral infections were identified by the presence of the antibodies to these viruses in the patient's blood samples.

Results

Out of the 19,137 HNSCC patients registered, 156 patients had HBV, HCV, and/or HIV infection. Among these, HBV infection was the most common (n = 86/156, 55.1%) followed by HIV infection (n = 36/156, 23.1%) and HCV infection (n = 29/156, 18.6%). The oral cavity was the most common subsite involved. Majority of these patients presented at an advanced stage (advanced T stage - 71.8% and node positive - 62.2%). The majority of the patients received curative-intent treatment (65.4%). The OS at 3 years for these HNSCC patients with coexisting HIV, HBV, and HCV infection was 60%, 62.6%, and 57.5%, respectively, and their DSS at 3 years was 58.8%, 78.6%, and 53.8%, respectively.

Conclusions

Seropositive patients with HNSCC often present in the advanced stage but have a good survival if treated appropriately.

Metronomic palliative chemotherapy in locally advanced, recurrent and metastatic head-and-neck cancer: A single-arm, retrospective study of a regional cancer center of North India (Asia)

Background

Head-and-neck cancer is the most common cancer in developing countries of Southeast Asia. Most of the patients present to the hospital in advanced stage and have a poor prognosis. This study aims to evaluate the efficacy and toxicity profile of oral metronomic chemotherapy (MCT) in the form of methotrexate and celecoxib in locally advanced, recurrent and metastatic head-and-neck cancers.

Materials and Methods

This was a single-arm retrospective observational study that included posttreatment patients with locally advanced, recurrent and metastatic disease in the year 2016 (January 1, to December 31, 2016). A total of 84 patients warranting palliative chemotherapy but not willing to take intravenous chemotherapy were included in the study. The oral MCT schedule consisted of oral celecoxib (200 mg twice daily) and oral methotrexate (15 mg/m²/week). Response evaluation was done using the Response Evaluation Criteria in Solid Tumors criteria version 1.1, and toxicity profile was assessed using the National Cancer Institute Common Terminology Criteria for Adverse Events version 4.03. Descriptive statistics and Kaplan-Meier analysis were performed.

Results

Eighty-four patients, 68 males and 16 females, with a median age of 62 years (range: 35-80 years), were enrolled in the study to receive oral MCT. The Eastern Cooperative Oncology Group performance status was 0-1 in 62 patients and 2-3 in 22 patients. The primary sites of disease were buccal mucosa (18), tongue (22), tonsil (24), lower alveolus (7), hypopharynx (10), and soft palate (3). The best clinical response rate in post oral MCT was seen in the first 4 months (120 days). Objective response was observed in 67% of patients in the form of stable disease (56%) and partial response (11%). Disease progression was observed in 27% of patients. The median follow-up was 192 (6.4 months) days. The median estimated overall survival was 195 (6.5 months) days. The median estimated progression-free survival was 110 (3.6 months) days. Symptomatic relief with respect to pain was reported in about 75% of patients. Eighteen (21%) patients had Grade I-II mucosal reactions. Grade III-IV mucosal reactions were observed in five (6%) patients. Seventy-eight (93%) patients died at the end of the study at 1 year. Dose reduction was required in 15 (18%) patients.

Conclusion

Oral MCT using celecoxib and methotrexate is an effective, economical, and well-tolerated regimen with good pain control and low toxicity profile in patients with locally advanced, recurrent and metastatic head-and-neck cancer.

Emergency Department Visits by Head-and-Neck Cancer Patients

Aim:

This study was conducted to assess the disease status of head-and-neck cancer patients visiting the emergency department (ED) and their reason for presentation. We wanted to analyze if these visits could be avoided by incorporating any changes in our clinical practice.

Methods:

This was a retrospective analysis of head-and-neck cancer patients attending the ED at a tertiary care cancer center in 2017. Clinical details were noted from the electronic medical records, and descriptive statistics was calculated. The analysis was performed using SPSS version 21 software.

Results:

Three hundred and thirty-nine head-and-neck cancer patients attended the ED. Of these, 80.2% were males and 48.1% of patients had oral cavity cancers. About 37.2% required palliative care treatment. Nearly, 47.2% of patients presented during their initial evaluation period. About 22.7% required hospital admission and only 14.7% required any sort of emergency intervention.

Conclusion:

Majority of visits to ED could have been avoided with better counseling of the patients and their attendants.