The choice of a local treatment method for solitary lung metastases: surgery or stereotactic radiation therapy

Objective. To improve of treatment results in functionally inoperable patients with solitary lung metastases. Material and methods. At the P. Herzen Moscow Oncology Research Institute, 133 patients aged 24 to 88 years with solitary lung metastasis were combined into two groups. In group 1, 67 patients (27 (40.3%) women and 40 (59.7%) men) received stereotactic body radiotherapy (SRT); in group 2, 66 patients (32 (48.5%) women and 34 (51.5%) men) received surgical treatment (ST). Histological structure of the primary tumor: in adenocarcinoma SRT was used in 27 (40.3%) patients, ST — in 35 (53.0%); in squamous cell cancer SRT was performed in 24 (35.8%), ST — in 15 (22.7%); in ductal cancer SRT was performed in 6 (9%), ST — in 6 (9.1%); in sarcoma SRT was performed in 4 (6%), ST — in 3 (4.6%), in other cases (once detected non-repeating morphological forms of tumor) SRT was used in 6 (8.7%), ST — in 7 (10.6%). When the size of the metastasis was less than 5 cm, SRT was performed in 86.6% of cases, ST — in 86.4%; more than 5 cm, SRT — in 13.4%, ST — in 13.6%. All patients in the SRT group were found to be functionally inoperable. For peripherally located metastases, a single focal dose (SFD) of 15 Gy was brought to a total focal dose (TFD) of 45—60 Gy; for centrally located metastases, the SFD was 8 or 10 Gy, TFD — 30—50 Gy. SRT was performed on Elekta linacs using the breathing control system ABC and verification of the target position in front of each fraction (XVI). Volume of CL: atypical lung resection was performed in 33 (50%) cases, lobectomy — in 29 (43.9%), segmentectomy — in 2 (3%), pneumonectomy — in 2 (3%). Results. In the SRT group (median follow-up 28 months), RTOG1 radiation pneumonitis was detected in 18 (26.9%) patients. In the ST group (median follow-up 34 months) 6 (9.1%) patients had postoperative complications: bleeding (n=1; 1.5%), postoperative wound suppuration (n=2; 3.0%), pneumonia (n=3; 4.6%). Local recurrence was diagnosed in 3 cases (4.5%) with SRT, and in 4 cases (6.1%) with ST. Local control within 1 year and 3 years in the SRT group was achieved in 97 and 95.5% of cases, in the ST group — in 95.4 and 93.9%, respectively. Overall 1- and 3-year survival rates for SRT were 82.1 and 49.1%, and for ST — 81.8 and 46.2%, respectively. There were no significant differences in the groups in terms of recurrence rate, local control and overall survival (p>0.05). Conclusion. The effectiveness of SRT in the treatment of solitary lung metastases in functionally inoperable patients, in terms of recurrence rate, local control and overall survival, did not differ statistically significantly from the results obtained in the surgical treatment group.