Prognostic factors in the treatment of node-negative nonsmall cell lung carcinoma with radiotherapy alone

Abstract

Purpose : For patients with early stage nonsmall cell lung carcinoma (NSCLC) but medically inoperable, aggressive radiation therapy might impact on survival. Methods and Materials : Between 1980 and 1990, 71 patients treated at MDACC by radiation therapy alone for NSCLC because of medical contradindications for surgery were analyzed. All patients had histologic or cytologic confirmation of NSCLC. The median total radiation dose was 63.23 Gy with 79% of patients receiving doses exceeding 60 Gy. The radiography response was documented at completion of radiation therapy and 6 months after completion of radiation therapy. The median follow-up time was 36 months, ranging from 14–61 months. Results : Overall survival rates at 3 and 5 years were 19 and 12%, respectively. The disease-specific survival (DSS) rates at 3 and 5 years were 44 and 32%, respectively. The DSS rates at 3 years by T-stage were: 49% for T1, 47% for T2, 26% for T3, and 32% for T4. The local control rates at 3 and 5 years were 66 and 56%, respectively. The local control rates at 3 years by T-stage were: 89% for T1, 61% for T2, 42% for T3, and 55% for T4. Univariately, the significant favorable prognostic factors for DSS were a KPS ≥ 70, tumor size ≤ 5 cm, no chest-wall invasion, and a radiation dose ≥ 50 Gy. The significant favorable prognostic factors for local control were tumor size ≤ 4 cm, no chest-wall invasion, a radiation dose >60 Gy, and a complete response confirmed by chest x-ray at 6 months after radiotherapy ( p = 0.04). Coverage of nodal drainage areas did not affect survival or local control. No lethal complications were seen, and documented symptomatic radiation pneumonitis occurred in only 7% of cases. Hence, the significant favorable prognostic factors for DSS were a KPS of ≥ 70, tumor size ≤5 cm, no chest-wall invasion, and a radiation dose ≥50 Gy. The significant favorable prognostic factors for local control were tumor size of ≤4 cm, no chest-wall invasion, a radiation dose >60 Gy, and a complete reponse confirmed by chest x-ray at 6 months after radiotherapy. Multivariate analysis showed that the most important prognostic factor for DSS was KPS, and the most important prognostic factor for local control was radiation dose. Conclusion : Patients with a KPS of ≥70, a tumor size <5 cm, and no chest-wall invasion would benefit most from treatment with radiation alone to doses exceeding 60 Gy. This patient group represents the best sample for studying the benefit of conformal radiotherapy.