BACKGROUND/AIM:Adaptive radiation therapy (ART) is a technique capable of reducing radiation dose to normal tissue without compromising local control. For potentially resectable thymoma, induction therapy is standard of care. Because large disease volume is common in this context, ART has been suggested to reduce toxicity from induction chemoradiation. This has not been previously illustrated in the literature.CASE REPORT:A 38-year-old man with initially unresectable thymoma was treated with induction chemoradiation including cisplatin and etoposide. He received 45 Gy in 25 fractions and ART was utilized to shrink the radiotherapy field for the final 10 fractions.RESULTS:Thymectomy showed Masaoka stage III disease with negative margins. He experienced no treatment-related toxicity and has no evidence of disease 8 years after diagnosis.CONCLUSION:Induction chemoradiotherapy with ART appears to be feasible, safe, and efficacious for locally advanced intact thymoma.

Objective The purpose of this study is to determine whether the use of helical tomotherapy can reduce dose to the heart, breast tissue, and thyroid gland in children receiving whole lung irradiation (WLI). Methods Computed tomography simulation scans from nine pediatric patients previously treated with WLI were used for this dosimetry study. Each scan was alternatively planned using helical tomotherapy to minimize dose to surrounding critical structures. The clinical target volume (CTV) included both lungs. The ribs and spine in proximity to the lungs were included in the CTV to minimize bone asymmetry resulting from partial irradiation. The planning target volume (PTV) included the CTV with a 0.8-cm margin. The following structures were contoured: right atrium, left atrium, right ventricle, left ventricle, right and left breast, thyroid gland, and the humeral heads. Median dose ( D med ), minimum dose ( D min ), and maximum dose ( D max ) for the PTV, CTV, heart chambers, thyroid gland, right and left breast as well as right and left humeral heads were also obtained. Results The median PTV receiving the prescription dose was 97 %, with PTVs ranging from 95 to 99 %. The average D med for each of the four chambers of the heart ranged from 37 to 55 % of the prescription dose. The average D med for the breasts ranged from 88 to 95 % while for the thyroid gland was 10 % of the prescription dose. Conclusion Helical tomotherapy can minimize the radiation dose delivered to nontarget organs such as the heart, breasts, and thyroid gland.

Stereotactic body radiation therapy (SBRT) is a novel treatment modality in radiation oncology that delivers a very high dose of radiation to the tumor target with high precision using single or a small number of fractions. SBRT is the result of technological advances in patient/tumor immobilization, image guidance, and treatment planning and delivery. This modality is safe and effective in both early stage primary cancer and oligometastases. Compared to the use of stereotactic radiosurgery for other tumor sites, SBRT is slow to be adopted in the management of genitourinary malignancies. There are now emerging data that show the safety and efficacy of this treatment modality in genitourinary (GU) malignancies especially in prostate cancer and renal cell carcinoma. Preclinical data, clinical experience, and challenges are reviewed and discussed.