Potential applications of imaging and image-guided radiotherapy for brain metastases and glioblastoma to improve patient quality of life.

Treatment of glioblastoma multiforme (GBM) and brain metastasis remains a challenge because of the poor survival and the potential for brain damage following radiation. Despite concurrent chemotherapy and radiation dose escalation, local recurrence remains the predominant pattern of failure in GBM most likely secondary to repopulation of cancer stem cells. Even though radiotherapy is highly effective for local control of radio-resistant tumors such as melanoma and renal cell cancer, systemic disease progression is the cause of death in most patients with brain metastasis. Preservation of quality of life (QOL) of cancer survivors is the main issue for patients with brain metastasis. Image-guided radiotherapy (IGRT) by virtue of precise radiation dose delivery may reduce treatment time of patients with GBM without excessive toxicity and potentially improve neurocognitive function with preservation of local control in patients with brain metastasis. Future prospective trials for primary brain tumors or brain metastasis should include IGRT to assess its efficacy to improve patient QOL.

Feasibility of image-guided radiotherapy based on helical tomotherapy to reduce contralateral parotid dose in head and neck cancer.

BACKGROUND: To evaluate the feasibility of image-guided radiotherapy based on helical Tomotherapy to spare the contralateral parotid gland in head and neck cancer patients with unilateral or no neck node metastases. METHODS: A retrospective review of 52 patients undergoing radiotherapy for head and neck cancers with image guidance based on daily megavoltage CT imaging with helical tomotherapy was performed. RESULTS: Mean contralateral parotid dose and the volume of the contralateral parotid receiving 40 Gy or more were compared between radiotherapy plans with significant constraint (SC) of less than 20 Gy on parotid dose (23 patients) and the conventional constraint (CC) of 26 Gy (29 patients). All patients had PTV coverage of at least 95% to the contralateral elective neck nodes. Mean contralateral parotid dose was, respectively, 14.1 Gy and 24.7 Gy for the SC and CC plans (p < 0.0001). The volume of contralateral parotid receiving 40 Gy or more was respectively 5.3% and 18.2% (p < 0.0001) CONCLUSION: Tomotherapy for head and neck cancer minimized radiotherapy dose to the contralateral parotid gland in patients undergoing elective node irradiation without sacrificing target coverage.

Feasibility of tomotherapy to reduce normal lung and cardiac toxicity for distal esophageal cancer compared to three-dimensional radiotherapy.

PURPOSE: To compare the effectiveness of tomotherapy and three-dimensional (3D) conformal radiotherapy to spare normal critical structures (spinal cord, lungs, and ventricles) from excessive radiation in patients with distal esophageal cancers. MATERIALS AND METHODS: A retrospective dosimetric study of nine patients who had advanced gastro-esophageal (GE) junction cancer (7) or thoracic esophageal cancer (2) extending into the distal esophagus. Two plans were created for each of the patients. A three-dimensional plan was constructed with either three (anteroposterior, right posterior oblique, and left posterior oblique) or four (right anterior oblique, left anterior oblique, right posterior oblique, and left posterior oblique) fields. The second plan was for tomotherapy. Doses were 45 Gy to the PTV with an integrated boost of 5 Gy for tomotherapy. RESULTS: Mean lung dose was respectively 7.4 and 11.8 Gy (p=0.004) for tomotherapy and 3D plans. Corresponding values were 12.4 and 18.3 Gy (p=0.006) for cardiac ventricles. Maximum spinal cord dose was respectively 31.3 and 37.4 Gy (p < 0.007) for tomotherapy and 3D plans. Homogeneity index was two for both groups. CONCLUSIONS: Compared to 3D conformal radiotherapy, tomotherapy decreased significantly the amount of normal tissue irradiated and may reduce treatment toxicity for possible dose escalation in future prospective studies.

Impact of image-guided radiotherapy to reduce laryngeal edema following treatment for non-laryngeal and non-hypopharyngeal head and neck cancers.

We would like to determine the effectiveness of image-guided radiotherapy (IGRT) to reduce laryngeal edema following treatment for head and neck cancer and to assess patient perception of voice and speech after treatment. We conducted a retrospective review of 44 patients undergoing radiation for non-laryngeal and non-hypopharyngeal head and neck cancers. Endoscopic and/or mirror examinations of the larynx were performed following radiotherapy at each follow-up visit. Laryngeal edema was assessed based on the Radiation Therapy Oncology Group grading scale. Patients were also asked to rate about the voice and speech quality relative to their pre-radiotherapy status. The mean laryngeal dose was 16.3 Gy (range: 11.7-45.5 Gy). At a median follow-up of 14 months (range: 2-31 months), three patients (7%) developed laryngeal edema (one grade 1, two grade 2). The mean laryngeal dose was respectively 20.3 Gy in two patients and 20.7 Gy in the third patient developing laryngeal edema. Except for one patient who continued to smoke and drink after radiotherapy, no patient reported any significant change in voice and speech quality after treatment. IGRT results in low rates and low severity of laryngeal edema following treatment for non-laryngeal and non-hypopharyngeal head and neck cancers and may preserve voice quality.

Feasibility of tomotherapy for Graves' ophthalmopathy: Dosimetry comparison with conventional radiotherapy.

PURPOSE: To compare the dosimetry of tomotherapy and the conventional half-beam technique (HBT) or non-split beam technique (NSBT) for target coverage and radiation dose to the lacrimal glands and lens. PATIENTS AND METHODS: A retrospective review of 7 patients with Graves' ophthalmopathy who had radiotherapy because of disease progression on high steroid dose is reported: 3 patients were treated with tomotherapy and 4 patients with HBT. RESULTS: Compared to HBT, tomotherapy may provide better target coverage and significant reduction of radiation dose to the lacrimal glands and a higher dose to the lens. The NSBT improved target coverage but resulted in significantly higher doses to the lens and lacrimal glands. CONCLUSION: Tomotherapy may provide better coverage of the target volume and may be more effective in reducing severe exophthalmos compared to the conventional radiotherapy technique.

Pattern of failure following chemoradiation for locally advanced non-small cell lung cancer: potential role for stereotactic body radiotherapy.

Standard of care for locally advanced non-small cell lung cancer has been concurrent chemoradiation. However, optimal chemotherapy regimen, radiation therapy dose and treatment volume have not been clearly defined despite 30 years of controlled clinical trials. This review analyzes survival and failure pattern reported from randomized studies of chemoradiation for non-small cell lung cancer. Despite introduction of new chemotherapy agents, survival remained poor; rates of both locoregional failures and distant metastasis remained high. The current radiation dose appears insufficient to reliably establish local control. Stereotactic body radiotherapy may allow radiation dose escalation and should be tested in future clinical trials.

Effectiveness of image-guided radiotherapy for laryngeal sparing in head and neck cancer.

We would like to compare the effectiveness of image-guided (IGRT) and intensity-modulated (IMRT) radiotherapy to spare the larynx in head and neck cancer patients. A retrospective review of 48 patients undergoing radiation for non-laryngeal and non-hypopharyngeal head and neck cancers. Mean laryngeal and hypopharyngeal dose was compared between 11 patients treated with IMRT and 37 patients treated with IGRT. Mean laryngeal dose was, respectively, 41.2 Gy and 22.8 Gy for the IMRT and IGRT technique (p<0.001). The radiation dose to the middle and inferior pharyngeal muscles was also significantly reduced with the IGRT technique. Mean pharyngeal dose was, respectively, 52 Gy and 26 Gy for the IMRT and IGRT technique (p=0.0001). Laryngeal sparing IGRT technique for head and neck cancer minimizes radiotherapy dose to the larynx and pharynx without sacrificing target coverage, even in the presence of neck lymph nodes.

Can stereotactic fractionated radiation therapy become the standard of care for early stage non-small cell lung carcinoma.

Management of early stages non-small cell lung carcinoma has traditionally been surgery with radiation selected for medically inoperable patients. Recent emergence of stereotactic body radiation therapy allows for delivery of high radiation dose to the tumor while sparing normal lungs. This reviews compares loco-regional control, survival and complications rates between these two treatment modalities. Literature search identifies studies with stereotactic body radiation therapy and surgery for early stages non-small cell lung cancer. Effectiveness and toxicity of these two modalities was assessed. Stereotactic body radiation therapy is associated with minimal morbidity and provides comparable local control and survival in patients with multiple co-morbidities factors. Stereotactic body radiation therapy may become standard of care for operable early stages non-small cell lung cancer.