Efficacy of limb salvage with primary tumor resection simultaneously for solitary bone metastasis in limbs

In metastatic cancer, the bone is one of the most likely metastatic sites just following the lung and the liver. Bone metastases often occur in some cancers, including breast cancer, prostate cancer, kidney cancer, thyroid cancer, and lung cancer, of which breast cancer and prostate cancer take the lead [1]. Seventy percent of bone metastases occur in the axial skeleton, while 10 % in the limbs. Limb bone metastases occur in the proximal long bones, such as the proximal humerus and the proximal femur [2]. Patients with bone metastases often experience severe complications, including pain, limited mobility, hypercalcemia, pathologic fracture, spinal cord compression, or nerve root compression, which will seriously affect the patient’s quality of life, thereby affecting the treatment of the primary tumor [3]. In cancer patients, emergence of bone metastases usually implies that the diseases are in the middle or final term. Therefore, improving the quality of life, alleviating local symptoms, and curing relative complications are the primary purposes for bone metastases.

As reported in the previous literature, the general surgical treatment of limb bone metastases was amputation [4]. But now, the most well accepted therapy is the palliative surgical treatment or the limb salvage surgery including chemotherapy, radiotherapy, bisphosphonate, and analgesic drug therapy [5]. For bone metastases in limbs, palliative surgery mainly aims to treat or lower the risk of the pathologic fracture of the long bone and the hip. The primary surgical approaches include plate fixation, large segment resection and reconstruction, intramedullary nails, and external fixation. Hardman et al. reported that taking the preventive internal fixation treatment for limb bone metastases has more favorable effort in prolonging survival and improving the quality of life than that after pathological fracture [6]. Studies have shown that patients with solitary bone metastasis have a better prognosis than those with multiple ones [7]. Therefore, for patients whose solitary bone metastasis was manifested as the first sign, wide or marginal excision for the primary lesion and bony metastasis focus according to treatment principles of the primary bone tumor can improve the patients’ quality of life. This group of patients received limb salvage surgery with primary tumor resection simultaneously. To analyze the efficacy of this strategy, the pain, quality of life, limb function, tumor-free survival time, and postoperative complications were evaluated.

Metastatic bone cancer is a common malignancy. Most malignant tumors involve in bone metastases, 80 % of breast, prostate, and lung cancer are in the process [10]. In our study, the primary cancers involved lung cancer (n = 8), breast cancer (n = 3), kidney cancer (n = 4), prostate cancer (n = 2), thyroid cancer (n = 1), cervical cancer (n = 1), and gastric cancer (n = 1). Nowadays, the treatment of bone metastases is a comprehensive therapy. Although radiation therapy play a role in pain control and prevention of pathological fractures, surgery is more effective in functional recovery and prevention of the progression of local tumor [11]. Moreover, patients with bone metastases are usually older; they can hardly withstand the long-term and highly toxic chemotherapy. Thus, moderate surgery has a positive significance for patients with bone metastases. Surgical approaches vary in different patients. Factors affecting the surgical methods include age, systemic condition, and extent of bone metastases, the existence of metastases outside the bone, as well as the patient’s wishes [12].

Bone metastases are the most common first manifestation of lung cancer, kidney cancer, myeloma, and lymphoma. Although breast and prostate cancer are the most common primary sites of bone metastases, they rarely take bone metastases as the first manifestation [13]. However, in our group, bone metastases were recognized as the first manifestation in all patients, and further examination revealed the primary tumor. For metastatic cancer patients without pathological fracture, it is advisable to receive non-surgical treatment. While for most patients with pathological fracture, limb salvage surgery is a preferable choice [14]. Pathological fracture occurs mainly in the proximal end of the bone and the backbone (Fig. 2). Therefore, the surgical fixation methods vary according to the metastatic tumor site. For fracture adjacent to the joint, tumor resection, and prosthetic replacement are mainly used. Six patients with pathological fracture adjacent to the joint underwent tumor resection and prosthetic replacement. When the fracture locates in the backbone, bone cement filling with intramedullary nailing is the better choice [15]. For bone metastases, patients without pathological fracture, Mirels et al. considered that if a total Mirels score of 8 or greater was identified, it was advisable to take measures to prevent the occurrence of pathologic fractures. If the Mirels score was greater than 9, the risk of pathological fractures rises to 33 %, it is necessary to take preventive internal fixation [16]. Studies have shown that, in the lung cancer, patients with bone metastases, limb salvage surgery with primary tumor resection simultaneously could significantly improve their survival time and prognosis (Fig. 3) [17, 18]. In the 20 patients of this group, bone metastases were recognized as the first performance of clinical manifestations, and further examination revealed the primary lesion. Among them, 18 received salvage treatment, consisting of tumor resection and prosthetic replacement, simultaneously with the resection of the primary tumor. For prostate cancer patients, one patient received endocrine therapy after limb salvage surgery; the other was given castration therapy. Pain was alleviated, and the quality of life was improved significantly after surgery.

In this group, 11 patients received wide resection of metastatic tumor, while 9 patients received marginal resection together with postoperative radiotherapy as an adjuvant therapy, which also received good control of the local tumor. No local recurrence was observed in this group. And there was no significant difference between the patients with wide resection and those with marginal resection in their tumor-free survival time. Bauer reported that in Karolinska hospital, nine kidney cancer patients with solitary bone metastases underwent wide or marginal resection with no local recurrence or implant failures during follow-up [13]. Similarly, as reported in literature, the presence of primary cancer and poor performance status were identified as independent prognostic factors using Cox regression multivariate analysis; however, surgical margin was not significantly related to patient survival [19]. Cho also showed that wide resection conveyed no survival advantage over curettage in patients with solitary bone metastasis from hepatocellular carcinoma [20]. Therefore, wide or marginal tumor resection is not the major factor in determining the tumor-free survival time.

In short, for the bone metastases, patients whose solitary bone metastasis was manifested as the first sign, limb salvage surgery with primary tumor resection simultaneously according to the treatment principles of primary bone cancer can reduce the patients’ pain and improve their quality of life, without increasing the rate of local recurrence. However, as the patients were followed up in a relative short time, the impact of limb salvage therapy on patients’ overall survival needs further follow-up.