Pulmonary Interstitial Lymphography in Early Stage Lung Cancer

Overview

The stereotactic body radiation therapy (SBRT) procedure is an emerging alternative to the standard treatment for early stage non-small cell lung cancer (NSCLC), typically lobectomy with lymphadenectomy. This procedure (lobectomy) does not fulfill the medical need as many patients are poor operative candidates or decline surgery. This study assesses the feasibility of stereotactic body radiation therapy (SBRT) as a tool to produce therapeutically useful computed tomography (CT) scans, using standard water-soluble iodinated compounds as the contrast agents.

Non-small cell lung cancer (NSCLC) is the most deadly cancer in the world. NSCLC annually causes 150,000 deaths in the US and greater than 1 million worldwide. The standard treatment for early stage NSCLC is lobectomy with lymphadenectomy. However, many patients are poor operative candidates or decline surgery. An emerging alternative is Stereotactic Body Radiation Therapy (SBRT). Mounting evidence from phase 1-2 studies demonstrates that SBRT offers excellent local control. Most SBRT trials focused on small, peripheral tumors in inoperable patients. Increasingly, clinical trials study SBRT in operable patients, often with larger, central tumors. Using clinical staging, a significant proportion of patients harbor occult nodal metastases when undergoing SBRT to the primary tumor alone. Subgroups of patients carry even higher risk of nodal metastases. These nodal metastases frequently would be removed by surgical intervention. However, SBRT, at present, is only directed at the primary tumor, potentially leading to regional failures in otherwise curable patients. To increase the effectiveness of SBRT for lung tumors, the next logical step is to explore whether the highest risk areas of disease spread can be identified and targeted. Regional failure could be reduced and outcome improved in a significant proportion of patients treated with SBRT if the primary nodal drainage (PND) were identified, targeted and treated in addition to the primary tumor. We propose to conduct a study to determine the feasibility of visualizing, by computed tomography (CT) scans, water-soluble iodinated contrast materials after direct injection into the tumor. Integration into radiation therapy treatment planning may also be assessed.