Recently, the number of osteosarcomas has been increasing in elderly patients due to human longevity. In a nationwide Japanese database from 2006 to 2013, 183 out of 1497 patients (22%) with osteosarcomas were found in the age of more than 65 years old [4]. The need for studies on elderly patients with osteosarcomas is therefore increasing. Several papers have reported on poor prognosis of the elderly patients with osteosarcomas [3, 4, 10]. Longhi et al. reported that the median survival and 5-year overall survival were 19 months and 22%, respectively, in 43 patients who had high-grade osteosarcoma and were older than 65 years.
Lung metastases are the primary cause of death from osteosarcomas. Complete surgical resections of all pulmonary lesions contribute to prolonged survival [5]. However, surgical resection in elderly patients with osteosarcomas is not always applicable. In fact, multiple surgical series have reported greater perioperative mortality in the elderly [11, 12].
Percutaneous CT guided RFA has been reported to provide a safe and effective minimally invasive treatment for lung metastases [13]. Lung RFA was introduced in 2000 [14], and applied to patients with osteosarcoma in 2009 [9]. Thereafter, several authors have reported the feasibility of this technique in patients with lung metastases from osteosarcomas (Table 1). However, no paper has reported any patient older than 65 years with high-grade osteosarcoma and with lung metastases treated by percutaneous CT-guided lung RFA. In addition, the importance of the present case is the longest follow-up among patients with osteosarcomas treated by this technique (Table 1).
In our institute, RFA is applied to tumor size of 3 cm or less. Basically, the electrode is placed in the center of the tumor when the tumor size is 2 cm or less. When the tumor size is larger than 2 cm, the electrode is placed sequentially at 2–4 different sites in the tumor based on size and shape [13]. A maximum of 3 lung tumors, developing in one lung, can be treated on the same day.
The advantage of RFA is that it allows ablation of tumors without major damage to the surrounding normal parenchyma. It has been demonstrated that RFA does not change lung function parameters and is possible even in patients with severe respiratory dysfunction [15]. In addition, this technique can be performed percutaneously under moderate sedation and local anesthesia. It can be applied several times in patients with severe co-morbidities or/and elderly patients. In the present case 8 lung RF procedures could be performed.
The risk of failure of RFA is in patients with large pulmonary lesions. In such a case, surgical resection should be considered. The advantages and disadvantages of RFA and surgical resection for the patient with sarcoma lung metastases are summarized in Table 2. The usefulness of combination therapy of RFA and surgical resection has been shown against lung metastases for improvement of curability [7, 16].
The most frequent complication is pneumothorax requiring chest tube drainage, which occurs in approximately in 10–23% of the procedures [6–8]. Nakamura et al. reported the feasibly of RFA in elderly patients more than 65 years old with soft tissue and bone sarcomas. In their series, chest tube drainage was required in 15 out of 65 procedures (23%) in 12 patients, which was not statistically different from the results of sarcoma patients younger than 65 years. In the present osteosarcoma case, pneumothorax occurred in 4 of 8 (50%) and chest tube drainage was needed in 2 of 8 (25%) lung RF procedures. However, no serious clinical deterioration was found.
In conclusion, percutaneous CT-guided lung RFA is a less invasive and safe technique for the elderly patient of more than 65 years, with lung metastases of osteosarcoma. The present patient has been alive with disease for 5.5 years after initial surgery.