Elective nodal irradiation in the treatment of non-small-cell lung cancer with three-dimensional conformal radiation therapy

Purpose: Dose escalation using three-dimensional conformal radiation therap y (3D-CRT) has been investigated as a means to improve local control. Howev er, with higher doses, the risk of toxicity increases. Early in our experie nce, we ceased treating elective nodal areas (lymph node stations without e vidence of tumor involvement) in an effort to decrease toxicity while treat ing the gross tumor to higher doses. This report measures the rate of regio nal failure without elective radiation therapy to uninvolved lymph nodes. Methods and Materials: A total of 171 patients with non-small-cell lung can cer treated with 3D-CRT at Memorial Sloan-Kettering Cancer Center between 1 991 and 1998 were reviewed. Only lymph node regions initially involved with tumor either by biopsy (55%) or radiographic criteria (node greater than o r equal to 15 mm in the short axis on CT) were included in the clinical tar get volume. Elective nodal failure was defined as a recurrence in an initia lly uninvolved lymph node in the absence of local failure. Results: Only II patients (6.4%) with elective nodal failure were identifie d. With a median follow-up of 21 months in survivors, the 2-year actuarial rates of elective nodal control and primary tumor control were 91% and 38%, respectively. In patients who were Locally controlled, the 2-year rate of elective nodal control was 85%. The median time to elective nodal failure w as 4 months (range, 1-19 months). Most patients failed in multiple lymph no de regions simultaneously. Conclusion: Local control remains one of the biggest challenges in the trea tment of non-small-cell lung cancer. Most patients in our series developed local failure within 2 years of radiation therapy. The omission of elective nodal treatment did not cause a significant amount of failure in lymph nod e regions not included in the clinical target volume. Therefore, we will co ntinue our policy of treating mediastinal lymph node regions only if they a re clinically involved with tumor. (C) 2001 Elsevier Science Inc.