[Therapeutic analysis of stereotactic radiotherapy for 39 patients with lung metastasis].

BACKGROUND & OBJECTIVE: There are only a few traditional treatment methods for lung metastasis, and the therapeutic effectiveness is not satisfactory. X-ray stereotactic radiotherapy (SRT) is developed as a new treatment option of lung metastasis in recent years. This study was to summarize the efficacy of SRT on lung metastasis.

METHODS

A total of 39 patients with 62 lung metastatic lesions were treated by SRT in Cancer Center of Sun Yat-sen University. The median maximum diameter of the targets was 2.1 cm (1.2-4.9 cm), and the median maximum volume of the targets was 1.4 cm(3) (0.3-16.9 cm(3)). Of the 62 lesions, 21 were irradiated by single fraction with a dose of 20-24 Gy, and 41 were irradiated by 2-4 fractions with a dosage of 8-16 Gy/fraction and a total dose of 24-45 Gy. The median biologic effective dose (BED) of all lesions was 75 Gy (52.8-112.5 Gy).

RESULTS

Response rate was 83.3% at 3 months after treatment. For the lesions with maximum diameter of < or =3 cm, the response rates were 62.5% for BED<75 Gy and 93.5% for BED> or =75 Gy (P=0.023). Median survival time was 21.6 months (3.4-62.2 months). The 1-year and 2-year overall survival rates, local control survival rates and progression-free survival rates were 78.9% and 48.2%, 88.4% and 82.8%, 65.0% and 39.3%, respectively. The 2-year overall survival rate was significantly higher in the subgroup with single lung metastatic lesion than in the subgroup with multiple lung metastatic lesions (57.7% vs. 30.0%, P=0.047), and significantly higher in the subgroup without metastasis in other organs than in the subgroup with metastasis in other organs (54.9% vs. 28.6%, P=0.003). The occurrence of radiation pneumonitis (> or =grade 2) was 5.1% (2/39).

CONCLUSIONS

SRT is an effective and safe treatment for lung metastasis. The patients with single lung metastasis and without metastasis in other organs have better survival. BED> or =75 Gy has better local control effect on lung metastasis with maximum diameter of < or =3 cm.