Stereotactic radiotherapy for pulmonary metastatic neoplasm-preliminary experience of 52 patients

Objective: To investigate the result and effecting factors of local control of pulmonary metastatic tumor treated with stereotactic radiotherapy(SRT). Methods: From January 2000 to December 2004, 52 patients with 133 pulmonary metastatic lesions were treated with SRT. Among these 52 patients, 34 were male and 18 female, with ages ranging from 16 to 84 years (median 58 years). Twenty-eight patients had pulmonary metastasis only in the lung and 24 had concurrent metastasis in other sites. Thirty-seven patients received one course of SRT, and 15 multiple courses. Among 133 metastatic lesions, 8(8%) were squamous carcinoma, 22 (17%) adenocarcinoma, 23(17%) hepatic carcinoma, 11(8%) sarcoma, and 69(52%) other types which were refractory and insensitive to chemotherapy and radiotherapy. One center was used in 127(95.5%) lesions, and two centers for 6(4.5%). The collimator was 7(5% )with 20-25 mm, 38(29%) 27.5-30.0 mm,53(40%) 32.5- 40.0 mm, and 35(26% ) 40-50 mm, respectively. The target volume varied from 0.13 to 35.3 cm3 with a median of 2.8 cm3. Reference dose was defined with 90% isodose covering the target in patients using one center and 50%- 80% in patients using two centers. Non-ring simulating technique with golden particles preset in the body was used. The treatment was performed using 4 to 6 arcs delivering with noncoplanar isocenter beams. Dose-fraction modality varied according to the lesion: 30-36 Gy/3F/14-18 days for 28 foci;40-48 Gy/5-8F/12 days for 32 foci; 48-52 Gy/4F/12-15 days for 25 foci; 45 Gy/3F/10days or 54 Gy/4F/12 days for 8 foci; 58-60 Gy/5-6F/15-20 days with 19 foci;40 6y/2F/6-8 days,50 Gy/5F/12 days or 60-66 Gy/10-11F/12-15days for 21 foci. Results: Of the 133 lesions, complete response was observed in 88(66%), and partial response in 23(17%), stable dis- ease in 7(5%), progressive disease in 5(4%), and the rest 10(8%) could not be evaluated. The effective rate was 84% (112/133). The overall local control rate was 89% (119/133). No serious complication was observed in the whole groups. The median follow-up time was 16 months. The mean survival time was 33 months. The median survival time was 24 months. The 1-, 2-, 3-, and 4-year survival rate was 79%, 50%, 45% and 33%, respectively Conclusions: Ster eotactic radiotherapy is sale and effective for pulmonary metastatic lesion. It, being indicated either for one single or multiple lesions, can be performed with multiple courses. The pathology of the lesion and too low a dose are the two main effecting factors to local control of stereotactic radiotherapy. (authors)