Metastases to the Pelvis: Algorithm of Treatment

Introduction. Patients with pelvic bone metastasis present a wide range of symptoms, and therapeutic strategies should be individualized in order to obtain the best possible quality of life despite the advanced stage of disease. A multidisciplinary approach among the oncologist, radiation therapist, and orthopedic surgeon is mandatory. The goals of treatment in these patients are pain control, maintenance of independence and prevention of tumor progression, and improvement of the quality of remaining life. We propose a treatment algorithm for patients with bone metastasis in the pelvis. This algorithm aims to simplify the choices of the team from diagnosis to treatment and to avoid under- or overtreatment of pelvic bone metastases. Material and Methods. We conducted a comprehensive review of the literature for clinical studies that reported diagnosis, modalities of treatment, pain relief and function outcomes, as well as perioperative complications and mortality, in patients with bone metastasis to the pelvis and/or acetabulum. Multiple databases from the experienced centers involved were searched up to June 2016. Data have been analyzed in order to prepare an algorithm of treatment based simply on questions with yes/no answers, from diagnosis to follow-up. Results. The algorithm consists of 11 questions that guide physicians since the discovery of a pelvic bone lesion. Treatments are reported in squares and included biopsy, nonsurgical treatment group, radiotherapy, minimally invasive palliative procedures (MIPPs), noninvasive MR-guided FUS (focused ultrasound), surgery, and embolization. In acetabular involvement, the amount of the periacetabular bone loss was classified according to Harrington classification (ranging from groups I to IV) and metastatic acetabular classification (MAC, ranging from types 1 to 4). Conclusion. The treatment of cancer patients with bone metastases is multidisciplinary. Currently, modern treatments are available for the palliative management of patients with metastatic bone disease. These include modern radiation therapy, chemotherapy, embolization, electrochemotherapy, radiofrequency ablation, MIPPs, and MR-guided FUS. Special attention should be directed to osteolytic lesions in the periacetabular region, as they can provoke pathologic fractures and subsequent functional impairment. Different reconstruction techniques for the pelvis are available; the choice depends on the patient’s prognosis, size of the bone defect, and response of the tumor to adjuvant treatment. If all the conservative treatments are exhausted and the patient is not eligible for surgery, one of the various MIPPs can be considered.