Complications of bone tumors after multimodal therapy

To define and compare the complications of bone tumors after resection, extracorporeal irradiation and re-implantation, with or without radiotherapy.

Eighty patients (40 males and 40 females, ages 4-77 years) with 61 malignant and 19 benign bone tumors were evaluated for local and distant complications after treatment. Two groups of patients were studied: (1) 53 patients had resection without (43 patients) or with external beam radiotherapy (RadRx) (10 patients) and (2) 27 patients underwent extracorporeal irradiation and re-implantation without (22 patients) or with RadRx (5 patients). Patient follow-up varied from 1 month to 13.63 years with mean follow-up of 4.7 years. Imaging studies included bone and chest radiography, spin echo T1- and T2-weighted (or STIR) magnetic resonance imaging (MRI), dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), computed tomography (CT) for thoracic and abdominopelvic metastases and 3-phase technetium-99m-labeled-methylene-diphosphonate (Tc99m MDP) scintigraphy for bone metastases.

DCE-MRI differentiated the rapidly enhancing recurrences, residual tumors and metastases from the slowly enhancing inflammation, and the non-enhancing seromas and fibrosis. Recurrences, metastases (mainly to lung and bone), and seromas were greater than twice as frequent in patients after resection than after ECCRI. Although 11.3% of post-resection patients had residual tumor, no ECRRI-treated patient had residual tumor. In contrast, after ECRRI, infection was almost three times as frequent and aseptic loosening twice as frequent as compared with the post-resection patients. Bones treated with RadRx and/or ECRRI showed increased prevalence of fractures and osteoporosis. In addition, muscle inflammation was more common in the externally irradiated patient as compared with the patient who did not receive this therapy. However, another soft tissue complication, heterotopic ossification, was rare in the patient after RadRx, but 25.6% of patients after resection and 40.9% after ECRRI showed heterotopic ossification. Unusual complications after resection or ECRRI involved adjacent nerves with partial denervation, amputation neuroma, or entrapment (secondary to recurrence or fibrosis) after resection or ECRRI with or without RadRx. One patient developed a posterior tibial artery pseudoaneurysm after ECRRI.

Follow-up of patients with benign and malignant bone tumors demonstrated the efficacy of DCE-MRI for distinguishing rapidly enhancing viable tumor from the slowly enhancing or non-enhancing benign processes after different therapies. Although recurrences, residual tumors, metastases and seromas were more common after resection, fractures, osteoporosis, infection, and muscular atrophy predominated in the ECRRI-treated patient. RadRx further predisposed post-resection and post-ECRRI patients to develop fractures, osteoporosis and infection and was the major cause of persistent muscle inflammation at MRI. Because complications can evolve and resolve years after treatment, the patients with bone tumors, particularly sarcomas, must receive life-time multimodal imaging for maximal diagnosis and treatment.