The Musculoskeletal Tumor Society is a small cadre of dedicated professionals whose mission is to advance the science of orthopaedic oncology and to promote high standards of patient care. It does this through excellence in education and research. The Society specializes in the treatment of sarcomas and limb-salvage surgery. Over the years, the Society has had a diverse and broad range of research interests, all in an effort to improve patient care. Research has involved basic science and molecular genetics of sarcomas and musculoskeletal neoplasms, limb- salvage techniques and reconstruction alternatives, and improvement of survival and outcome analysis. The Society prides itself on its members, whose interests parallel those of the Society and who are dedicated academicians, clinician scientists and surgeons specializing in the most complex of procedures and remaining passionate care givers. This symposium represents fourteen papers presented at the 2005 annual meeting (Nashville, Tennessee, May 19-21), chosen to represent the broad spectrum of research interests of the Society. The Society wishes to thank CORR and its Editor-in-Chief for this opportunity.
Optimizing the functional outcome of limb salvage surgical reconstruction following tumor resection about the knee was the subject of five papers. The McGill group discussed mega endoprosthesis reconstruction for the distal femur. After analyzing the long-term outcome of 77 patients with a mean followup of four years, they concluded the reconstruction was durable and highly functional. The ten year implant survival rate was 79%. There was no stem loosening.
“Continuity and Function of Patella Tendon Host- Donor Suture in Tibial Allograft” was presented by members of the Ottolenghi Hospital of Buenos Aires. Forty-two sarcoma patients who had resection of the proximal tibia including the extensor mechanism were studied utilizing a reconstructive option of allograft patellar tendon reconstruction to the native patellar tendon. Active knee extension was restored to all patients and the reconstruction proved reliable.
The Seattle group, “Distal Femur and Proximal Tibia Mega Prosthesis Survival,” investigated the length of time from implantation to first failure. In their experience, implants surviving 5 years had an excellent chance of long- term survival. Approximately 1⅓ of the implants failed and 69% of the failures occurred within the first 5 years.
Approaches to “Endoprosthetic Reconstruction for Neoplasms of the Proximal Femur” was reported by the University of Southern California group. Ninety six patients treated with megaprostheses with a range of followup from 1 to 129 months and an average of 11½ years had a survival of 82% at 10 years. Bipolar cups had a lower revision rate than conventional total hip cups.
The Toronto group discussed their findings of “Aseptic Loosening is Uncommon with Uncemented Proximal Tibia Tumor Prostheses.” This retrospective study followed 44 patients from 9 to 152 months with an average followup of 5 years. Operative complications occurred in 12 out of 44 patients, but there were no cases of aseptic loosening.
Secondary cancers are becoming more frequent as our success at treating primary malignancies improves. Three authors discussed their experiences with this evolving problem.
Members of the MD Anderson Cancer Center discussed “Outcome of Post-radiation Osteosarcoma Does Not Correlate with Chemotherapy Response.” A dismal survival result was reported for this high-risk group and histologic response to chemotherapy did not correlate with survival.
The Vanderbilt group presented the multi-institutional results of “Multifocal Postradiation Sarcomas.” A new entity was brought to light in that all of the tissues in a radiated bed are subject to late malignant transformation and thus need to be considered for definitive surgical resection before and after a postradiation sarcoma occurs. Multifocality was not a significant variable related to survival. Many female patients who underwent breast conserving lumpectomy followed by radiation were victims of multifocal postradiation sarcomas.
Members from Toronto presented the multi-institutional results detailing that “Prognosis of Radiation-Induced Bone Sarcoma is Similar to Primary Osteosarcoma.” Combined multidrug chemotherapy and aggressive surgical techniques were noted to have similar outcomes, as did primary osteosarcomas. A subgroup of individuals (10 of 17) had resectable localized sarcoma.
The remaining papers reflect a variety of topics of importance to musculoskeletal tumor surgeons. The “Mechanical Effects of Partial Sacrectomy” by the Mayo Clinic group determined the mechanical consequences of various sacrectomy levels using cadaver pelvi. By measuring the load to failure, the authors concluded that trans- verse sacrectomy below the S1 exiting nerve root weakens the pelvis by about 1⅓, whereas above the S1 foramen weakens the pelvis by about 2⅓. This has translational implications for deciding when early weight bearing may be initiated in the postsacrectomy patient.
“Myxoidfibrosarcoma in the Upper Extremity” by the Memorial Cancer Center group described the capricious nature of this apparent low-grade soft tissue sarcoma that has a very high local recurrence rate of around 50%. MRI evaluation suggests a unique pattern of diffuse spread along facial planes that needs to be taken into account during surgical management and treatment to maximize margin-free resection.
The University of Pennsylvania group reported their experience with “Percutaneous Biopsy of Musculoskeletal Tumors.” Thirty of the 120 studied patients (25%) required closed biopsy followed by open biopsy to establish the correct diagnosis. Accurate interpretation of closed biopsies is institution dependent.
The Carolinas Medical Center discussed the “Role of PET Scanning in Pediatric Bone Sarcomas.” As this rapidly evolving technology becomes more commonly utilized, it appears that in this retrospective study at a single institution, a 7% upstaging was observed solely because of the sensitivity of this imaging modality in 55 young patients with Ewing's or osteosarcoma of bone.
The Vanderbilt group discussed the “Evolving Technology of Proteomics in the Evaluation and Profiling of Soft Tissue Sarcomas.” Matrix assisted laser desorption ionization mass spectrometry (MALDI-MS) analysis allows hundreds of peptides and proteins to be detected from intact tissues. Liposarcomas had a different proteomic profile than lipoma. MALDI-MS offers the promise of identifying clinically useful biomarkers because it can detect which proteins are expressed in malignant fat, but not benign fat.
The Pittsburgh group explored the hypothesis that certain mouse osteosarcoma cell lines in vitro may have greater metastatic potential when expressing growth factors like VEGF and BMP2. Noggin, a BMP antagonist, may block this action.
In summary, these papers reflect the many ongoing research fronts of the Musculoskeletal Tumor Society in terms of molecular genetics, proteomics, limb salvage and outcome analysis. The Society remains committed to the advancement of patient care, survival and quality of life in this extremely complex and challenging area of cancer care.
Herbert S. Schwartz, MD
Department of Orthopaedics Vanderbilt University Nashville, TN; and
Eugene R. Mindell, MD
Department of Orthopaedics Buffalo General Hospital Buffalo, NY