Quantitative Comparison of Dosimetric Data Between the Indigenous Baseplate and Commercially Available Carbon Fiber Baseplate for 6 and 15 MV Photon Energy.

Background: This study aims to design an indigenous baseplate (ID baseplate) that is economically viable and dosimetrically comparable for radiotherapy patient treatment. An ID baseplate was designed and manufactured using wood plastic composition materials that are readily available in the market and were compared dosimetrically with the commercially available carbon fiber baseplate (CF baseplate). Materials and Methods: Surface dose and beam attenuation properties of both the baseplates (ID and CF) were measured using a parallel plate chamber and compared with the dose calculated from the treatment planning system (TPS). Separate computer tomography images of both the baseplates were acquired by placing solid water phantoms. These images were used for surface dose calculation in the TPS and were validated with experimental measurements. Proper densities were assigned to the couch and baseplates to avoid uncertainties in dose calculations. All measurements were performed at field sizes 10 cm × 10 cm for 6 MV and 15 MV photon beams. Results: The percentage surface dose measured for the ID baseplate and CF baseplate was found to be matching for 6 MV beam (98.2% and 97%, respectively); however, for the 15 MV beam, the ID baseplate showed a higher surface dose of 98.6% compared to CF baseplate (87.4%). For the ID baseplate, the percentage difference in the surface dose between that TPS calculated value and the measured values were 1.6% and 1.4% for 6MV and 15MV, respectively. The ID baseplate showed higher beam attenuation than the CF baseplate by 2.2% for the 6MV beam and 3.4% for the 15MV beam when proper electron densities were not assigned. The difference between the TPS calculated dose and delivered dose was achieved within 3% after assigning proper electron density to the couch and baseplate. Conclusions: The ID baseplate has shown acceptable dosimetric results and can be an economically viable alternative to the commercially available CF baseplates. The manufacturing cost of the ID baseplate was ten times cheaper than the CF baseplate.

Questionnaire survey to assess the pattern and characteristics of cell-phone usage among Indian oncologists.

PURPOSE: Obtain baseline data of cell-phone usage in the medical (MO), surgical (SO) and radiation (RO) oncology community practicing in India. MATERIALS AND METHODS: Indigenously prepared cell-phone usage related questionnaire was used in the present study after approval by the Institutional Ethics/Scientific Committees. The questionnaire had 41 items and was made to assess the cell-phone usage parameters, utility in clinical practice, awareness, and to compare parameters between oncology specialties. Between November 2009 and January 2010, the questionnaire was sent as an E-mail attachment to 200 oncologists in India. RESULTS: In all, 123 responses were received (61% responders); 84 (68.3%) were RO. The median age of responders was 35 years. Overall, 80% felt handicapped without cell-phone. The Mean cell-phone score, an index to assess overall usefulness over a score of 1-10, was 6.46 (median 7, standard deviation 1.709). There was no significant difference between RO, MO and SO in duration of usage (P = 0.235), number of cell-phones (P = 0.496), call duration per day (P = 0.490) and dependence on cell-phone (P = 0.574). Age of starting cell-phone usage was earlier in RO (P = 0.086). Professional usage was significantly more by MO and SO compared to RO (P < 0.001); however, the former were less aware of any potential cell-phone hazards compared to RO (P < 0.007). CONCLUSION: The results of the first such questionnaire based study have been presented. Most oncologists consider cell-phones a useful tool in patient care. More RO are aware of potential cell-phone hazards compared to non-RO's.

Adaptive radiation therapy for pediatric head and neck malignancies: Dosimetric implications.

PURPOSE: This study was designed to evaluate the role of adaptive radiation therapy for children receiving curative radiation therapy to the head and neck region. METHODS AND MATERIALS: Ten children receiving definitive, conformal radiation therapy to the head and neck region were prospectively evaluated for anatomic changes during the course of radiation therapy. Images were acquired midway through the number of planned radiation therapy fractions during the planned course of radiation therapy. Body contours, target volumes, and organs at risk were redrawn on the new set of images. Two sets of additional treatment plans were generated: (1) a nonoptimized plan (plan 2), that is, an overlay of the original plan (plan 1) on the new set of contours, and (2) an optimized plan (plan 3) with the new set of contours. These 3 sets of plans were then compared for dosimetric differences. RESULTS: Five children had nasopharynx carcinoma, whereas the other 5 had embryonal rhabdomyosarcoma. The average reduction in gross tumor volume was 40% (mean volume, 41.87 mL; P = .005). The average changes in right and left parotid volumes were 2.72 and 1.92 mL, respectively. With nonoptimized plans, the average increase in maximum dose to the spinal cord was 15% (79.99%-94.99%; P = .013). With reoptimization, the maximum dose to the spinal cord decreased from 94.99% to 85.26% (mean difference, -9.73%; P = .02). Average D99 for the planning target volume (dose received by 99% of the target volume) was 88.66% and 86.89% with the original and reoptimized plans, respectively (P = .50). For the entire group, the mean conformation number index with nonoptimized plans was reduced from 0.734 to 0.628 (P = .013). This improved with reoptimization (P = .114). The homogeneity index improved with reoptimization from a mean value of 0.113 to 0.098 (P = 0.28). For nonoptimized plans, the average integral dose increased from 74.66 to 76.27 L-Gy (P = .486) compared with the original plans. Reoptimization resulted in a 5% average reduction in the integral dose, from 76.27 to 72.28 L-Gy (P = .007). CONCLUSIONS: This study demonstrates the usefulness of adaptive radiation therapy for children receiving radiation therapy to the head and neck region.

Prospective analysis of reasons for non-enrollment in a phase III randomized controlled trial.

AIM: This study aims to provide information on the accrual rate and to identify the reasons for non-enrollment of oral cancer patients into a clinical trial. SETTING AND DESIGN: Prospective study conducted at the Tertiary Cancer Centre (India). MATERIALS AND METHODS: Patients eligible and screened for the oral cancer adjuvant therapy (OCAT) were logged prospectively and reasons for non-enrollment were documented which were broadly divided into patient and trial related. STATISTICAL ANALYSIS USED: Demographic characteristics of the non-enrolees were compared with the enrolled. Factors predicting non-enrollment were analyzed using multivariate logistic regression test. RESULTS: A total of 1335 patients with locally advanced cancer of the oral cavity were screened of whom 498 (37%) could be enrolled. Among non enrolled 837 patients, 182 (22%) had the trial-related reasons and 655 (78%) had patient-related reasons. Most important patient-related reasons were patients' preference of taking treatment closer to their native place (26.2%), lack of interest (16.8%) in trial participation. Anticipated poor compliance to treatment (5.9%) and follow-up (6.6%), inability to start treatment in time (6.2%) were important trial-related reasons for non-enrollment. Multivariate analysis identified the genders (female), education (illiterate), occupation (laborer) and non availability of support system in the city as significant predictors of non-enrollment. CONCLUSIONS: Both trial design and patient factors were important causes of non enrollment in eligible patients. Patients' need for being closer to home and refusal to participate were the most common reasons for non-enrollment.

Osteosarcoma of the head and neck region: lessons learned from a single-institution experience of 50 patients.

BACKGROUND: Osteosarcoma of the head and neck region is a rare tumor and is a therapeutic challenge because of its aggressive nature and complex anatomical location. Standard management guidelines are lacking due to paucity of published data. METHODS: Fifty patients with head and neck osteosarcoma treated at our institute from 1995 to 2004 were reviewed. RESULTS: There were 32 men and 18 women (median, 30 years). Mandible (56%) was the most common site. Chondroblastic (46%) was the most common histopathological variant. Treatment comprised multimodality approach using surgery (100%), radiotherapy (36%), and chemotherapy (58%). After a median follow-up of 16.6 months, 46% were alive and disease free. Median overall survival was 45.7 months, and progression-free survival was 13.7 months. Mandible and maxilla were favorable sites. Postoperative adjuvant radiotherapy improved local control in patients with adverse prognostic factors. CONCLUSIONS: Surgery remains the mainstay of the treatment of head and neck osteosarcoma. Adjuvant radiotherapy improves outcome in patients with adverse factors.