Sheh Rawat

Radiation-induced dental caries, prevention and treatment - A systematic review

Treatment of head and neck cancers (HNCs) involves radiotherapy. Patients undergoing radiotherapy for HNCs are prone to dental complications. Radiotherapy to the head and neck region causes xerostomia and salivary gland dysfunction which dramatically increases the risk of dental caries and its sequelae. Radiation therapy (RT) also affects the dental hard tissues increasing their susceptibility to demineralization following RT. Postradiation caries is a rapidly progressing and highly destructive type of dental caries. Radiation-related caries and other dental hard tissue changes can appear within the first 3 months following RT. Hence, every effort should be focused on prevention to manage patients with severe caries. This can be accomplished through good preoperative dental treatment, frequent dental evaluation and treatment after RT (with the exception of extractions), and consistent home care that includes self-applied fluoride. Restorative management of radiation caries can be challenging. The restorative dentist must consider the altered dental substrate and a hostile oral environment when selecting restorative materials. Radiation-induced changes in enamel and dentine may compromise bonding of adhesive materials. Consequently, glass ionomer cements have proved to be a better alternative to composite resins in irradiated patients. Counseling of patients before and after radiotherapy can be done to make them aware of the complications of radiotherapy and thus can help in preventing them.

Intensity modulated radiotherapy in abdominal malignancies: Our experience in reducing the dose to normal structures as compared to the gross tumor

BACKGROUND AND PURPOSE A better understanding of appropriate sequencing and use of multimodality approach in the management and subsequent improvement in overall survival mandates a vigil on quality of life issues. Intensity modulated radiotherapy (IMRT) is a powerful tool, which might go a long way in reducing radiation doses to critical structures and thereby reduce long term morbidities. The purpose of this paper is to evaluate the impact of IMRT in reducing the dose to the critical normal tissues while maintaining the desired dose to the volume of interest for abdominal malignancies. MATERIALS AND METHODS During the period January 2002 to March 2004, 11 patients of various sites of malignancies in the abdominal region were treated using physical intensity modulator based IMRT. Plans of these patients treated with IMRT were analyzed using dose volume histograms. RESULTS An average dose reduction of the mean values by 50% to the liver, 57% to the right kidney, 56% to the left kidney, 66% to the cord and 27% to the bowel, with respect to the GTV could be achieved with IMRT. The two-year disease free survival was 79% and two-year overall survival was 88%. The average number of IMRT fields used was six. CONCLUSION IMRT with inverse planning enabled us to achieve desired dose distribution, due to its ability to provide sharp dose gradients at the junction of tumor and the adjacent critical organs.

Comparison between weekly cisplatin‐enhanced radiotherapy and cetuximab‐enhanced radiotherapy in locally advanced head and neck cancer: First retrospective study in Asian population

To present a direct comparison between chemotherapy‐enhanced radiotherapy (CERT) and biotherapy‐enhanced radiotherapy (BERT) in locally advanced head and neck cancer.

Impact of Adaptive Radiotherapy on Locally Advanced Head and Neck Cancer - A Dosimetric and Volumetric Study

UNLABELLED Objective of the study is to evaluate volumetric and dosimetric alterations taking place during radiotherapy for locally advanced head and neck cancer (LAHNC) and to assess benefit of replanning in them. MATERIALS AND METHODS Thirty patients with LAHNC fulfilling the inclusion and exclusion criteria were enrolled in a prospective study. Planning scans were acquired both pre-treatment and after 20 fractions (mid-course) of radiotherapy. Single plan (OPLAN) based on initial CT scan was generated and executed for entire treatment course. Beam configuration of OPLAN was applied to anatomy of interim scan and a hybrid plan (HPLAN30) was generated. Adaptive replanning (RPLAN30) for remaining fractions was done and dose distribution with and without replanning compared for remaining fractions. RESULTS Substantial shrinkage of target volume (TV) and parotids after 4 weeks of radiotherapy was reported (p<0.05). No significant difference between planned and delivered doses was seen for remaining fractions. Hybrid plans showed increase in delivered dose to spinal cord and parotids for remaining fractions. Interim replanning improved homogeneity of treatment plan and significantly reduced doses to cord (Dmax, D2% and D1%) and ipsilateral parotid (D33%, D50% and D66%) (p<0.05). CONCLUSIONS Use of one or two mid-treatment CT scans and replanning provides greater normal tissue sparing alongwith improved TV coverage.

Retrospective analysis of treatment outcomes following reirradiation in locoregionally recurrent head and neck cancer patients: A single institutional study

To present a retrospective analysis of treatment outcomes following reirradiation in locoregionally recurrent head and neck cancer patients at our institute.

A quantitative comparison of gross tumour volumes delineated on (18F)‑FDG PET‑CT scan and CECT scan in head and neck cancers

Purpose: To compare quantitatively Gross tumor volume (GTV), both primary and nodal areas of head and neck cancers, delineated on [18F]-2fluoro, 2deoxy d-glucose-positron emission tomography/computed tomography ([18F]-FDG-PET-CT) scan to those delineated on Contrast-enhanced CT scan (CECT scan). Methods: A total of 26 consecutive patients with squamous cell cancers of head and neck were included in this study. The primary sites were oropharynx (n = 7), hypopharynx (n = 6), paranasal sinus (n = 6), nasopharynx (n = 4), oral cavity (n = 2), and one with unknown primary and secondary neck node. All patients underwent routine staging work-up. FDG-PET and CECT scans were performed with dedicated PET-CT scanner in single session as a part of the radiotherapy treatment planning for Intensity modulated radiotherapy/Image-guided radiotherapy. Results: All patients had abnormal increased uptake in PET-CT scans. PET-CT resulted in changes of CT-based staging in 8 of 26 patients (up-staged in 7 and down-staged in 1). The mean primary and nodal GTV volumes on PET-CT and CT were significantly different (primary: PET-GTV: 48.43 ± 53.21 cc vs. CT 54.78 ± 64.47 cc, P < 0.001; nodes: PET-GTV: 12.72 ± 15.46 cc vs. 11.04 ± 14.87 cc, P < 0.001). The mismatch between two target volumes was statistically significant (P = 0.03 for GTV primary, P = 0.04 for GTV node). Conclusion: Accuracy of delineation of GTV can be improved along with functional imaging using [18F]-FDG. These metabolically active volumes are significantly smaller than CT-based volumes and could be missed during conventional CT-based target delineations of GTVs.

Correlation of six-minute walk test, pulmonary function test and radiation pneumonitis in the management of carcinoma of oesophagus: A prospective pilot study

Purpose: To correlate six-minute walk test (6MWT) and pulmonary function test (PFT) with incidence of radiation pneumonitis (RP) while treating patients with oesophageal cancer with conformal radiotherapy. Methods: Forty-five patients were selected to the study protocol. Pulmonary evaluation was done objectively by chest x-ray (CXR), 6MWT and PFT and subjectively by symptoms of cough, dyspnoea and fatigue. These tests were performed before radiation and then repeated at 1, 3, 6 and 9 months after treatment. The dose-volume histogram (DVH) was used to derive doses received by lung and organs at risk. χ 2 -test was used for calculating the p value. Results: The walk distance change (WDC) correlated with the changes in PFT values ( p = 0.001) were done at 3 and 9 months after radiation, respectively. V30 values of ≥20% correlated with the incidence of acute pneumonitis ( p = 0.007). 6MVT/vital capacity (VC) values of ≤4 ft/l had a correlation with the incidence of clinically symptomatic RP at 9 months. Conclusion: 6MWT and PFT are supplementary to each other for assessing the lung function status; but their individual role in predicting RP is weak. However, they are complementary to each other in assessing the risk of radiation-induced lung dysfunction.

Prospective study of neoadjuvant chemoradiotherapy using intensity-modulated radiotherapy and 5 fluorouracil for locally advanced rectal cancer – toxicities and response assessment

Aims and objectives The past 2 decades witnessed the strengthening of evidence favoring the role of neoadjuvant chemoradiation (CHRT) in the treatment of locally advanced rectal cancer. The study aims to evaluate the response and acute toxicities to neoadjuvant CHRT using intensity-modulated radiotherapy (IMRT) in the treatment of rectal cancer. Predictive factors to achieve pathological complete response (pCR) were analyzed, as a secondary endpoint. Materials and methods All consecutive patients who underwent IMRT as part of neoadjuvant CHRT in the treatment of rectal cancer between August 2014 and December 2016 at a tertiary cancer care center were accrued for the study. The cohort underwent CHRT with IMRT technique at a dose of 50.4 Gy in 28 fractions concurrent with continuous infusion of 5 fluorouracil during the first and the last 4 days of CHRT. Surgery was performed 6 weeks later and the pathological response to CHRT was noted. Results Forty-three subjects were accrued for the study. Radiation dermatitis and diarrhea were the only observed grade ≥3 acute toxicities. Sphincter preservation rate (SPR) was 43.3%. pCR was observed in 32.6%. Univariate and multivariate logistic regression showed that carcinoembryonic antigen was the only independent predictive factor to achieve pCR. Conclusion IMRT as part of neoadjuvant CHRT in the treatment of locally advanced rectal cancer is well tolerated and gives comparable results with respect to earlier studies in terms of pathological response and SPR. Further randomized controlled studies are needed to firmly state that IMRT is superior to 3-dimensional conformal radiotherapy.

Reirradiation with IMRT for recurrent head and neck cancer: A single-institutional report on disease control, survival, and toxicity

AIM To study and explores the feasibility and efficacy of re-irradiation (Re-RT) for locally recurrent head and neck cancer (HNC) and second primary (SP) malignancies. BACKGROUND The most common form of treatment failure after radiotherapy (RT) for HNC is loco-regional recurrence (LRR), and around 20-50% of patients develop LRR. Re-irradiation (Re-RT) has been the primary standard of care in the last decade for unresectable locally recurrent/SP HNC. MATERIALS AND METHODS It was a retrospective analysis in which we reviewed the medical records of 51 consecutive patients who had received Re-RT to the head and neck region at our institute between 2006 and 2015. RESULTS Forty-eight patients were included for assessment of acute and late toxicities, response evaluation at 3 months post Re-RT, and analyses of locoregional control (LRC) and overall survival (OS). The median LRC was 11.2 months, and at 2 and 5 years the LRC rates were 41% and 21.2%, respectively. A multivariate analysis revealed two factors: initial surgical resection performed prior to Re-RT, and achievement of CR at 3 months after completion of Re-RT to be significantly associated with a better median LRC. The median OS was 28.2 months, and at 1, 2, and 5 years, OS were 71.1%, 55.9% and 18%, respectively. A multivariate analysis revealed initial surgical resection performed prior to Re-RT, and achievement of CR at 3 months post completion of Re-RT being only two factors significantly associated with a better median OS. Acute toxicity reports showed that no patients developed grade 5 toxicity, and 2 patients developed grade 4 acute toxicities. CONCLUSION Re-RT for the treatment of recurrent/SP head and neck tumors is feasible and effective, with acceptable toxicity. However, appropriate patient selection criteria are highly important in determining survival and treatment outcomes.

Dental Pulp Status of Posterior Teeth in Patients with Oral and Oropharyngeal Cancer Treated with Concurrent Chemoradiotherapy

INTRODUCTION The absence of tooth sensitivity has been observed in patients who have undergone radiotherapy. The aim of this investigation was to evaluate the effects of concurrent chemoradiotherapy on the pulp status of posterior teeth in patients with malignant oral and oropharyngeal cancer. METHODS Twenty-one patients diagnosed with malignant oral and oropharyngeal cancer undergoing concurrent chemoradiotherapy underwent cold thermal pulp sensitivity testing and electric pulp testing of 4 teeth, 1 from each quadrant, at 4 points in time (PT): before radiotherapy (PT1), after 30-35 Gy (PT2), at the end of radiotherapy at 66-70 Gy (PT3), and 4 months (PT4) after beginning radiotherapy. RESULTS All 84 teeth tested positive to cold thermal pulp sensitivity testing at PT1 (100%) and 25 teeth at PT2. No tooth responded at PT3 and PT4 (100%). A statistically significant difference (P < .05) existed in the number of positive responses between different points in time. CONCLUSIONS Radiotherapy decreased the number of teeth responding to pulp sensitivity testing after doses greater than 30-35 Gy.