The Effect of Flattening Filter Free on Three-dimensional Conformal Radiation Therapy (3D-CRT), Intensity-Modulated Radiation Therapy (IMRT), and Volumetric Modulated Arc Therapy (VMAT) Plans for Metastatic Brain Tumors from Non-small Cell Lung Cancer

211 Background: In recent years, there has been a transition from two-dimensional radiation therapy (2DRT) planning towards more advanced techniques such as three-dimensional conformal radiation therapy (3D-CRT), volumetric modulated arc therapy (VMAT), and stereotactic body radiation therapy (SBRT). Our study aim was to analyze these trends in the treatment of bone metastases. Methods: All patients aged 18 and older who had received palliative intent RT for bone metastases between 2009-2014 and referred to any 1 of 6 regional cancer centers in British Columbia, Canada were reviewed. Summary statistics were used to describe radiation technique patterns. Logistic regression modeling was used to assess the influence of demographic, clinical, and health services variables on receipt of types of RT. Results: We identified 8,059 patients and 15,832 courses of RT; overall, 97.9% of courses were achieved by 2DRT and 2.1% by 3D-CRT, VMAT, or SBRT. Despite the low overall use of advanced techniques, its use was significantly higher in all subsequent years compared to 2009 (p < 0.05 for all years). The median age for patients treated with 2DRT was 67.0 (19-99) versus 66.0 years (19-93) for advanced techniques. There did not appear to be a statistically significant difference in age at the time of treatment start (OR 0.99; 95% CI 0.981-1.00, p < 0.05). Compared to lung cancers, thyroid (OR 9.9; 95% CI 5.197-18.724, p < 0.001) and kidney cancers (OR 3.9; 95% CI 2.508-5.911, p < 0.001) were significantly more likely to be treated with advanced techniques, while breast (OR 0.90; 95% CI 0.621-1.306, p = 0.58) and prostate cancers (OR 0.93; 95% CI 0.613-1.410, p = 0.73) were not any more likely. Compared to the Vancouver center, all other treatment centers in the province were utilizing advanced techniques less frequently. Patients were also more likely to complete RT with 2DRT than with advanced techniques (98.3% versus 95.8%, p < 0.05). Conclusions: The vast majority of treatment of bone metastases is still done by 2DRT in British Columbia. Despite these overall statistics though, a trend towards increasing use of more advanced techniques was observed.

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Dosimetric Analysis with Intensity-modulated Radiation Therapy for Central Nervous System Irradiation in Patients with Brain Cancer Compared with Three-dimensional Conformal Radiation Therapy Treatment

Polytechnic Journal ◽

10.25156/ptj.v9n2y2019.pp50-54 ◽

2019 ◽

Vol 9 (2) ◽

pp. 50-54

Author(s):

Noor S. Omer ◽

Runak T. Ali

Keyword(s):

Radiation Therapy ◽

Optic Nerve ◽

Brain Cancer ◽

Three Dimensional ◽

Intensity Modulated Radiation Therapy ◽

Optic Chiasm ◽

Imrt Plan ◽

Conformal Radiation Therapy ◽

Dosimetric Analysis ◽

3D Crt

Intensity-modulated radiation therapy (IMRT) was put as the development of three-dimensional conformal radiation therapy (3D-CRT). The purpose of the present study is to compare the dosimetric analysis of two techniques of radiotherapy (IMRT) and 3D-CRT, which include target volume and organ at risk for both plans. The present study enrolled that nine patients with different types of brain cancer which previously irradiated from November 2018 to May 2019 were selected in Zhianawa Cancer Center in Sulaymaniyah; all cases were planned again by both techniques 3D-CRT and IMRT. IMRT planning provides reducing the dose of both right and left optic nerve mean dose for right optic nerve 13.70 Gy and left 14.93 Gy compared with the 3D-CRT plan (right optic nerve 23.54 Gy and left 19.13 Gy). P = 0.2 for the right optic nerve and P = 0.56 for the left optic nerve were statistically significant. IMRT plan reduces dose to the optic chiasm compared to 3D-CRT plan, the mean dose of optic chiasm for IMRT was 33.37 Gy relative to 3D-CRT which was 34.28 Gy and P = 0.92. IMRT plan was better than 3D-CRT for many organs at risk, especially for optic chiasm and both optic nerve deliver less dose than 3D-CRT.

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