Musculoskeletal oncology

Figure 1. Musculoskeletal oncology is one of the most challenging fields of orthopaedics marrying the the extremes of surgical oncology and orthopaedic reconstruction but also providing some of the most stunning outcomes

Musculoskeletal oncology deals with tumors and tumorous conditions of the bones and joint. This encompasses all aspects of local and systemic control of disease and requires a multidisciplinary approach comprising the talents of orthopaedist, pediatric and adult medical oncologists, pediatric and adult general surgeons, plastic and hand surgeons, radiologists, radiation oncologists and musculoskeletal pathologist. Work in this area typically revolves around the traditional oncologic models based on therapeutic and molecular etiology but has, in addition, the aspects of functional issues and issues of social re-integration. Sarcomas pose challenging life-threatening problems and require great expertise not just in surgery but also in organizing multidisciplinary teams to tackle individual specific problems. Some musculoskeletal oncology conditions may not be life-threatening but, nevertheless, these problems provide unique challenges for medical practitioners because they often hamper daily activities and hence need to be dealt with urgently. This is one of the few specialties that encompass both pediatric and adult patients. There is an annual incidence of 30 cases of bone sarcomas and 120 cases of soft tissue sarcomas annually in Singapore alone. In addition, patients with metastatic disease will often require the care of the musculoskeletal oncologist for the management of metastatic disease.

Also known as bone sarcomas, osteosarcomas and chondrosarcomas are the two most common variants. These affect individuals of all ages but in particular people in the second and sixth decades of life. The challenges in managing these conditions revolve around removal of these tumors in a way that they do not recur and then reconstruct the structure to replace the missing anatomical structure and restore function. The general approaches to reconstruction can be both biological and prosthetic. In biological solutions the draw is that one is able to reconstruct the missing structure with biological materials and host bone which have a virtually life-long durability. These methods, however, do result in donor site morbidity and have a relatively high early complication rate. The prosthetic approach where joints and segments are replaced by metal implants have high patient acceptability and good function but are subject to wear.

Also known as soft tissue sarcomas, liposarcomas and malignant fibrous histiocytomas more commonly occur in adulthood whereas rhabdomyosarcomas and synovial sarcomas occur in childhood. The specific ability of the orthopaedic oncologists is in his ability to resect these tumors primarily to save life and yet secondarily reconstruct defects in a way that maintains function. In addition resections are done in a way that facilitates radiation therapy that is often used in these conditions.

When cancers in other parts of the body metastasize to the bone and soft tissues, these structures become compromised. As a result patients develop fractures that do not heal and they become invalid. This in turn reduces their life expectancy. Unique reconstructive measures allow these patients to remain active for prolonged periods until such time that terminal events result in their passing.

Benign tumors of the bones and soft tissues are commonly encountered and treated by general orthopedists and surgeons. Our special input in this field is in meeting two of the main challenges provided by these conditions. Firstly, these conditions provide diagnostic problems – that is they can be mistaken for more serious conditions like cancers. Our service works closely with the Departments of Pathology and Radiology with whom we meet regularly and such cases are amply discussed before embarking on surgery. This minimizes the risk of misdiagnoses. Next, when such conditions compromise function and need to be operated on (eg. Weakening the bone to the point that they may break) we would be able to reconstruct these conditions with minimal functional embarrassment.

Basic scientific research offers clues as to where the discipline may be heading. Osteosarcomas may be regarded as stem cell sarcomas for instance which accounts for the myriad phenotypes it presents with. Data from our service will be presented to show future directions in which therapeutics in this field may take. We are at the stage that tumors resected are now investigated in the laboratory in cell culture systems that look at how aggressive these tumors are. Furthermore, other collaborative efforts help us better understand the disease process at many levels beyond the basic imaging and surgical methods available to us presently.