Elective nodal failures are uncommon in medically inoperable patients with Stage I non–small-cell lung carcinoma treated with limited radiotherapy fields

Abstract 

Purpose

To review the outcome for 56 Stage I non–small-cell lung cancer treated definitively with three-dimensional conformal radiotherapy (3D-CRT) and to investigate the value of elective nodal irradiation in this patient population.

Methods and materials

Between 1992 and 2001, 56 patients were treated with 3D-CRT for inoperable Stage I histologically confirmed non–small-cell lung cancer; 31 with T1N0 and 25 with T2N0 disease. All patients were treated with 3D-CRT to a median isocenter dose of 70 Gy (range 59.94–83.85) given in daily doses of 1.8 or 2 Gy. Prognostic factors were analyzed with respect to their impact on overall survival. Twenty-two patients received radiotherapy (RT) directed to elective regional lymphatics to doses of 45–50 Gy. The remaining 33 patients were treated to limited fields confined to the primary lung cancer with a margin. The patterns of failure were reviewed.

Results

The median follow-up was 20 months (range 6 months to 6 years). The actuarial local control rate was 88%, 69%, and 63%, at 1, 2, and 3 years, respectively. The actuarial cause-specific survival rate was 82%, 67%, and 51% at 1, 2, and 3 years, respectively. The actuarial overall survival rate was 73%, 51%, and 34% at 1, 2, and 3 years, respectively. The actuarial metastasis-free survival rate was 90%, 85%, and 81% at 1, 2, and 3 years, respectively. The RT dose was the only factor predictive of overall survival in our analysis. No statistically significant difference was noted in cause-specific or overall survival according to whether patients received elective nodal irradiation. Two of 33 patients treated with limited fields had regional nodal failure.

Conclusion

Many patients with medically inoperable Stage I lung cancer die of intercurrent causes. The omission of the elective nodal regions from the RT portals did not compromise either the cause-specific or overall survival rate. Elective nodal failures were uncommon in the group treated with limited RT fields. A radiation dose ≥70 Gy was predictive of better survival in our population. We await the results of prospective trials evaluating high-dose RT in patients treated with RT alone for Stage I lung cancer.

Keywords:  Elective nodal irradiation, Stage I lung cancer, Medically inoperable, Three-dimensional conformal radiation therapy