Pulsed reduced dose-rate radiotherapy as re-irradiation for brain metastasis in a patient with lung squamous-celled carcinoma.

The recurrence and progression of brain metastases after brain irradiation are a major cause of mortality and morbidity in patients with cancer. The risk of radiation-induced neurotoxicity and efficacy probably leads oncologists to not consider re-irradiation. We report the case of a 48-year-old Asian male diagnosed with squamous cell lung cancer and multiple brain metastases initially treated with 40 Gy whole-brain radiotherapy and 20 Gy partial brain boost. Fourteen gray stereotactic radiosurgery as salvage for brain metastases in the left occipital lobe was performed after initial irradiation. The recurrence of brain metastases in the left occipital lobe was demonstrated on magnetic resonance imaging at 9 months after initial radiotherapy. He received the second course of 28 Gy stereotactic radiosurgery for the recurrent brain metastases in the left occipital lobe. The third relapse of brain metastases was demonstrated by a magnetic resonance imaging scan at 7 months after the second radiotherapy. The third course of irradiation was performed because he refused to undergo surgical resection of the recurrent brain metastases. The third course of irradiation used a pulsed reduced dose-rate radiotherapy technique. It was delivered in a series of 0.2 Gy pulses separated by 3-min intervals. The recurrent brain metastases were treated with a dose of 60 Gy using 30 daily fractions of 2 Gy. Despite the brain metastases receiving 162 Gy irradiation, this patient had no apparent acute or late neurologic toxicities and showed clinical improvement. This is the first report of the pulsed reduced dose-rate radiotherapy technique being used as the third course of radiotherapy for recurrent brain metastases.

The clinical feasibility and performance of an orthogonal X-ray imaging system for image-guided radiotherapy in nasopharyngeal cancer patients: Comparison with cone-beam CT.

The demand for greater accuracy of intensity-modulated radiotherapy (IMRT) has driven the development of more advanced verification systems for image-guided radiotherapy (IGRT). The purpose of this study is to investigate setup discrepancies measured between an orthogonal X-ray guidance system (XGS-10) and cone-beam computed tomography (CBCT) of Varian in the IMRT of patients with nasopharyngeal cancer (NPC). The setup errors measured by XGS-10 and CBCT at the treatment unit with respect to the planning CTs were recorded for 30 patients with NPC. The differences in residual setup errors between XGS-10 system and CBCT were computed and quantitatively analyzed. The time of image acquisition and image registration was recorded. The radiation doses delivered by CBCT and XGS-10 were measured using PTW0.6CC ionization chambers and a water phantom. The differences between setup errors measured by the XGS-10 system and CBCT were generally <1.5 mm for translations, indicating a reasonably good agreement between the two systems for patients with NPC in the translation directions of A-P (P = 0.856), L-R (P = 0.856) and S-I (P = 0.765). Moreover, compared with CBCT, XGS-10 took much shorter image acquisition and registration time (P <0.001) and delivered only a small fraction of extra radiation dose to the patients (P <0.001). These results indicate that XGS-10 offers high localization accuracy similar to CBCT and additional benefits including prompt imaging process, low imaging radiation exposure, real time monitoring, which therefore represents a potential attractive alternative to CBCT for clinical use.

Use of cetuximab in combination with pulsed reduced dose-rate radiotherapy in a patient with recurrence of nasopharyngeal carcinoma in the neck.

Reirradiation is a major therapeutic modality for patients with locally recurrent head and neck carcinoma. Due to normal tissue tolerances, reirradiation using conventional techniques has a narrow therapeutic ratio in the regional recurrence of nasopharyngeal carcinoma (NPC). Pulsed reduced dose-rate radiotherapy (PRDR), which delivers a series of 0.2 Gy pulses separated by 3 min intervals, is a new reirradiation technique. Head and neck carcinoma cells have high levels of epidermal growth factor receptor expression and cetuximab shows a clear benefit to locally advanced head and neck carcinoma. We report a 56-year-old male with a recurrent lesion of NPC in the neck following initial radical radiochemotherapy. The patient was retreated with PRDR and concurrent cetuximab. The total dose of PRDR was 70 Gy, using 35 daily fractions of 2.0 Gy. The recurrent lesion of this patient had a complete response with no apparent radiation-induced normal tissue complications. This is the first study concerning PRDR combined with cetuximab for the treatment of recurrent head and neck carcinoma following radiotherapy. The outcome of this patient reveals that treatment with PRDR and concurrent cetuximab is a promising therapeutic option for patients with recurrent head and neck carcinoma following radiotherapy.