Target definition and contouring in carcinoma of the lung and esophagus.

The optimal treatment for intrathoracic tumors such as lung and esophageal cancer requires an improvement of therapeutic ratio to increase efficacy of the cancer-cell kill and decrease the normal-cell kill. This is not an easy task because sensitive normal cells such as alveoli and epithelial cells in the esophagus and bronchus surround these tumors. How to minimize the damage of such sensitive normal cells within irradiated fields without sparing cancer cells is a major issue for radiation oncologists, especially as concurrent chemoradiotherapy has become more standard treatment. One way to achieve this task is accurate delineation of the target volume, which will be emphasized here. Some other ways to achieve it are biological protection by ethyol, keratinocyte growth factors, biologically targeted treatments such as C225 and celecoxib, and anti-angiogenesis, which have been briefly addressed in Dr. Cox's article in this Journal. Molecular imaging is a new diagnostic and therapeutic modality that offers great potential for accuracy of target definition, although it is not quite ready for routine clinical use at the present time. Accurate target definition and contouring in cases of carcinoma of the lung and esophagus depend on expertise of diagnostic and therapeutic medical teams. There we review the normal anatomy, diagnostic methods, and tumor delineation of cancer of the lung and esophagus.