Volumetric and geometric changes in the parotid glands and target volume during image-guided radiotherapy for locally advanced oropharyngeal cancers.

PURPOSE: This study aimed to evaluate the volumetric and geometric changes in the parotid glands and target volume during image-guided radiotherapy (IGRT) for locally advanced oropharyngeal cancers. MATERIALS AND METHODS: Twenty patients receiving radiotherapy using IGRT at a dose of 70 Gy/35 fractions/7 weeks for locally advanced oropharyngeal cancers were accrued. Radiotherapy planning computed tomography (CT) scans were performed at pre-radiotherapy (RT), 20, 40, and 60 Gy for each patient. Volume changes in target and parotids along with shifts of parotids were assessed with respect to pre-RT scan after co-registration. In study scans, GTVp and GTVn were recontoured as per particular CT. CTV and PTV were copied from planning CT to study CT. CTV was edited from anatomical barriers, and PTV was edited only from the skin in the study CT. The parotids were recontoured on each study scan. The center of mass (COM) of C2 vertebral body was considered as the reference to evaluate its shifts. RESULTS: There was a statistically significant percentage regression of ipsilateral and contralateral parotid mean volumes at the rate of 0.85%/0.207 cc and 0.98%/0.26 cc per day, respectively. We observed the mean medial shift of center of mass of ipsilateral parotid of 2.23 mm (p = 0.011) and contralateral parotid of 2.67 mm (p = 0.069) at the end of 60 Gy. GTVp (mean) reduced from 41.87 cc at 0 Gy to 31.13 cc (25.65%) at 60 Gy (p = 0.003), while GTVn (mean) reduced from 19.98 cc at 0 Gy to 10.79 cc (45.99%) at 60 Gy (p = 0.003). There was a statistically significant reduction in CTV and PTV volumes at 60 Gy. CONCLUSION: Statistically significant volumetric and geometric changes occurred during intensity-modulated radiation (IMRT), which were most prominent after 40 Gy and were maximum at 60 Gy. There was a medial shift of parotid glands toward the high-dose region. This study can be useful to devise an adaptive radiotherapy strategy.

Oral cavity adjuvant therapy (OCAT) -a phase III, randomized controlled trial of surgery followed by conventional RT (5 fr/wk) versus concurrent CT-RT versus accelerated RT (6fr/wk) in locally advanced, resectable, squamous cell carcinoma of oral cavity.

BACKGROUND: Limited data exists regarding the impact of intensification of adjuvant therapy in resected Oral Cavity Squamous Cell Carcinomas (OCSCC) with adverse prognostic features on histopathology. PATIENTS AND METHODS: This was a three-arm phase III, randomised trial including patients with resected advanced OCSCC. Randomisation was done in a 1:1:1 ratio: Arm-A- standard adjuvant radiation therapy (RT) 60Gy/30 fractions over 6 weeks versus Arm-B-concurrent chemoradiation versus Arm-C-accelerated radiation therapy (6 d a week). The trial was powered to detect an absolute difference of 10% in 5-year Locoregional Control (LRC). RESULTS: The trial was conducted between June 2005 and March 2013. Majority of the patients were males, had T3-T4 disease, had N2-N3 nodal status and had Extra-Capsular Extension (ECE) in nodes. The median follow-up was 95.9 months. There was no difference between the three arms (A versus B versus C) for 10-year locoregional control (LRC): 60.2% versus 61.4% versus 65.7%, p = 0.57; disease free survival (DFS): 37.4% versus 43.9% versus 39.6%, p = 0.40; or Overall Survival (OS): 39.7% versus 46.6% versus 40.4%, p = 0.40. There was no benefit of intensification with either modality in patients with any single adverse pathological factor. A benefit of intensification could be seen in patients with a combination of high-risk features: T3-T4 primary tumours with N2-N3 nodes along with ECE for DFS (Arm B versus Arm A HR) = 0.53, Arm C versus Arm A HR = 0.63) and OS (Arm B versus Arm A HR = 0.58, Arm C versus Arm A HR = 0.60). CONCLUSIONS: All optimally resected OCSCC with adverse features did not benefit from intensification of adjuvant therapy. Only a cohort of patients with a combination of high-risk features are likely candidates for intensification. CLINICAL TRIAL REGISTRATION: NCT00193843.

Setup error analysis in helical tomotherapy based image-guided radiation therapy treatments.

The adequacy of setup margins for various sites in patients treated with helical tomotherapy was investigated. A total of 102 patients were investigated. The breakdown of the patients were as follows: Twenty-five patients each in brain, head and neck (H and N), and pelvis, while 12 patients in lung and 15 in craniospinal irradiation (CSI). Patients were immobilized on the institutional protocol. Altogether 2686 megavoltage computed tomography images were analyzed with 672, 747, 622, 333, and 312 fractions, respectively, from brain, H and N, pelvis, lung, and CSI. Overall systematic and random errors were calculated in three translational and three rotational directions. Setup margins were evaluated using van Herk formula. The calculated margins were compared with the margins in the clinical use for various directions and sites. We found that the clinical isotropic margin of 3 mm was adequate for brain patients. However, in the longitudinal direction it was found to be out of margin by 0.7 mm. In H and N, the calculated margins were well within the isotropic margin of 5 mm which is in clinical use. In pelvis, the calculated margin was within the limits, 8.3 mm versus 10 mm only in longitudinal direction, however, in vertical and lateral directions the calculated margins were out of clinical margins 11 mm versus 10 mm, and 8.7 mm versus 7.0, mm respectively. In lung, all the calculated margins were well within the margins used clinically. In CSI, the variation was found in the middle spine in the longitudinal direction. The clinical margins used in our hospital are adequate enough for sites H and N, lung, and brain, however, for CSI and pelvis the margins were found to be out of clinical margins.

Incremental value of 18F-FDG PET/CT in therapeutic decision-making of potentially curable esophageal adenocarcinoma.

AIMS AND OBJECTIVES: The aim of the study was to estimate the incremental value of fluorine-18 fluorodeoxyglucose (F-FDG) PET/computed tomography (CT) in aiding treatment decisions in a specific cohort of patients with lower esophageal and gastroesophageal junction adenocarcinoma who were considered for potentially curative treatment on the basis of conventional imaging. MATERIALS AND METHODS: The study included patients referred for a staging F-FDG PET/CT who were considered for potentially curative treatment (neoadjuvant therapy followed by surgery or definitive chemoradiotherapy) by a multidisciplinary tumor board. The proportion of patients with M1b disease (American Joint Committee on Cancer, 6th ed.) detected on F-FDG PET/CT was calculated. The sensitivity, specificity, positive and negative predictive values, and accuracy of F-FDG PET/CT for M1b disease were calculated. PET/CT findings were verified with histopathological analysis; when it was not possible to obtain pathological confirmation, correlative imaging or follow-up imaging studies were used for validation. RESULTS: A total of 156 patients who fulfilled the inclusion criteria were analyzed. F-FDG PET/CT detected M1b disease in 25 patients (16%), changing the intent of treatment from potentially curative to palliative. In five patients, PET/CT failed to detect distant metastases. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of F-FDG PET/CT for detecting M1b disease were 83.3, 98.4, 92.5, 96.1, and 95.3%, respectively. Additional surgical procedures (hemicolectomy and polypectomy) were performed in three patients because of the detection of a second primary cancer in the colon in two patients and a colonic dysplastic polyp in one patient. CONCLUSION: In patients who are considered to be potentially curable after conventional imaging, F-FDG PET/CT can detect unsuspected sites of distant metastases (M1b) in a significant number of cases and thus contribute to the clinical decision-making process. PET/CT should be an integral part of the staging workup of patients with esophageal adenocarcinoma.

Toxicity with radiotherapy for oral cancers and its management: a practical approach.

Radiotherapy-induced damage in the oral mucosa is the result of the deleterious effects of radiation, not only on the oral mucosa itself but also on the skin, adjacent salivary glands, bone, dentition, and masticatory apparatus. From basic skin care to dental and oral health maintenance, several ointments and lotions, oral and parenteral medications, biological response modifiers, cytoprotective drugs, newer radiation techniques and surgery have been introduced to combat and more importantly to prevent the development of these complications. Radiotherapy-induced oral complications involve complex and dynamic pathobiological processes. This in the immediate- and long-term course lowers the quality of life and predisposes patients to serious clinical disorders. Here, we focus on these oral complications of radiotherapy, highlight preventive and therapeutic developments, and review the current treatment options available for these disorders.