Long-Term Weight Change Among Bone Sarcoma Survivors: A Retrospective Study

The purpose of this study was to track changes in weight/body mass index (BMI) during long-term follow-ups after treatment for primary bone sarcoma to assess the impact of clinicopathologic features and treatment modalities on weight. In an IRB approved protocol, we identified 221 adult patients with bone sarcoma treated at our institution between 1995 and 2013 who were disease free for over five years, and collected information on the weight at baseline and at least one year after completion of treatment for the primary tumor, including surgery, radiotherapy and chemotherapy. 94 patients were excluded due to insufficient data on weight and/or height. Association between maximum weight/BMI gain and clinical parameters were assessed by Student t test or ANOVA. The multivariate logistic regression was used to analyze weight outcomes and risk variables. Among the 127 patients, the median age was 46 years old (range: 18-78). There are 63 females and 64 males. Primary sites include head and neck (21, 16.5%), upper extremity (7, 5.5%), lower extremity (40, 31.5%), spine and pelvis (54, 42.5%), rib/clavicle/sternum (5, 3.9%). Histology includes osteosarcoma (73, 57.5%), chondrosarcoma (11, 8.7%), chordoma (32, 25.2%) and Ewing sarcoma (11, 8.7%). The average BMI at baseline was 26.82 (SE: 0.45), and 32 patients (25.2%) had a BMI above 30. 64 patients (50.4%) received chemotherapy, whereas 62 patients (48.5%) had radiotherapy. Along with tumor excision, 7 patients (5.5%) received arthroplasty in hip, 19 (15%) in knee, and 4 (3.1%) in shoulder; 22 patients (17.3%) underwent spinal stabilization. Five (3.9%) had lower extremity amputation. The median follow up was 9.6 years. The maximum weight gain was 3.37 kilograms on average, with an average change in maximum BMI gain of 1.16. Patients with younger age (<= 45 years old) had higher BMI gain (average: 1.62 vs 0.72, p=0.048). BMI gain was also higher in patients who had spine stabilization, lower extremity amputation, or arthroplasty in knee or hip (average: 1.82 vs 0.69, p=0.013). Multivariate logistic regression identified the surgery type as the only significant risk factor for BMI gain (p=0.013). There was no significant difference in BMI gain among different genders, primary tumor sites, histologies, tumor size, grade, chemotherapy, or radiotherapy. Bone sarcoma survivors who had spine stabilization, lower extremity amputation, or arthroplasty in knee or hip are at higher risk in weight gain in the long term, most likely due to reduced mobility. Rehabilitation should be an important component of returning to normal daily activities after treatment.