Clinical Outcome in Soft Tissue Sarcoma Patients with Lung Metastasis Who Received Metastasectomy and/or Radiofrequency Ablation: Tokai Musculoskeletal Oncology Consortium Study

Tomoki Nakamura,1 Kunihiro Asanuma,1 Motoshi Takao,2 Takashi Yamanaka,3 Hiroshi Koike,4 Toyofumi F Chen-Yoshikawa,5 Satoshi Tsukushi,6 Hiroaki Kuroda,7 Eiji Kozawa,8 Masaaki Sano,9 Hisaki Aiba,10 Ryoichi Nakanishi,11 Akihito Nagano,12 Kenji Yamada,13 Yoji Shido,14 Katsuhisa Kawanami,15 Yuya Izubuchi,16 Akihiro Sudo,1 Yoshihiro Nishida4,17 1Department of Orthopedic Surgery, Mie University Graduate School of Medicine, Tsu, Mie, Japan; 2Department of Thoracic Surgery, Mie University Graduate School of Medicine, Tsu, Mie, Japan; 3Department of Radiology, Mie University Graduate School of Medicine, Tsu, Mie, Japan; 4Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan; 5Department of Thoracic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan; 6Department of Orthopedic Surgery, Aichi Cancer Center Hospital, Nagoya, Aichi, Japan; 7Department of Thoracic Surgery, Aichi Cancer Center Hospital, Nagoya, Aichi, Japan; 8Department of Orthopedic Surgery, Nagoya Memorial Hospital, Nagoya, Aichi, Japan; 9Department of Thoracic Surgery, Nagoya Memorial Hospital, Nagoya, Aichi, Japan; 10Department of Orthopedic Surgery, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Aichi, Japan; 11Department of Oncology, Immunology and Surgery, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Aichi, Japan; 12Department of Orthopedic Surgery, Gifu University Graduate School of Medicine, Gifu, Gifu, Japan; 13Department of Musculoskeletal Oncology, Okazaki City Hospital, Okazaki, Aichi, Japan; 14Department of Orthopedic Surgery, Hamamatsu Medical University, Hamamatsu, Sizuoka, Japan; 15Department of Orthopedic Surgery, Aichi Medical University School of Medicine, Nagakute, Aichi, Japan; 16Department of Orthopedics and Rehabilitation Medicine, University of Fukui Faculty of Medical Sciences, Eiheiji, Fukui, Japan; 17Department of Rehabilitation, Nagoya University Hospital, Nagoya, Aichi, JapanCorrespondence: Tomoki NakamuraDepartment of Orthopaedic Surgery, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie, 514-8507, JapanTel +81592315022Fax +81592315211Email tomoki66@med.mie-u.ac.jpPurpose: Here, we investigated the oncological outcomes of lung metastasectomy and/or radiofrequency ablation (RFA) of 92 patients with soft tissue sarcoma (STS) at nine institutions.Methods: The study cohort included 65 men and 27 women with a mean age of 59 years at the time of metastasis. The mean follow-up duration was 51 months. All patients underwent metastasectomy and/or RFA for lung metastasis.Results: The mean maximum size of the initial lung metastasis was 14.6 mm. At the initial evaluation, 41 patients had a single metastasis, whereas 51 patients had multiple metastases. The mean number of metastasectomies and/or RFA was 2 per patient. A total of 70 patients underwent lung metastasectomy, whereas the other 13 underwent lung RFA. The remaining nine patients underwent both RFA and metastasectomy. The 5-year post-metastatic survival rate was 52%. The patients who underwent complete treatment for the initial metastasis had better post-metastatic survival rates than those who underwent incomplete treatment. A univariate analysis of all possible prognostic factors for complete treatment confirmed the predictive value of disease-free interval, metastasis at initial presentation, distribution, tumor size, and number of lung metastases. Of the 92 patients, 74 underwent complete treatment for initial metastasis; in these patients, univariate and multivariate analyses showed that a smaller tumor size and single-lung metastasis were prognostic factors for superior post-metastatic survival. The patients with a smaller (< 11.5 mm) single metastasis had better post-metastasis survival. The 5-year post-metastatic survival rates were 89.9% for patients with a smaller (< 11.5 mm) single metastasis versus 22.7% for patients with larger (> 11.5 mm) and multiple metastases.Discussion: We propose that complete treatment for lung metastasis in patients with STS may improve post-metastatic survival rates. Furthermore, tumor number and size are important variables for clinical decision-making.Keywords: lung metastasis, metastasectomy, radiofrequency ablation, soft tissue sarcoma