SLR - November 2013 - Laura Bohman

Do Malignant Bone Tumors of the Foot Have a Different Biological Behavior than Sarcomas at Other Skeletal Sites?

Reference: M. Brotzmann, F. Hefti, D. Baumhoer, A.H. Krieg (2013) "Do Malignant Bone Tumors of the Foot Have a Different Biological Behavior than Sarcomas at Other Skeletal Sites." Sarcoma.  2013; 2013: 767960.

Scientific Literature Review

Reviewed by: Laura Bohman, DPM
Residency Program: Cambridge Health Alliance

Podiatric Relevance: While primary bone tumors of the foot are rare, with malignant tumors only representing 15-25 percent, the severity of treatment and possible loss of life demands further research. Historically, malignant bone tumors are more prevalent and better understood in different parts of the body. However, little is known about how these deadly tumors behave when originating in the foot. This article evaluates the delay in diagnosis, the tumor size, and the long-term survival rate of patients with malignant bone tumors of the foot.

Methods: Thirty-two records from the Bone Tumor Reference Center database of Basel were collected of patients who were diagnosed with a primary bone tumor of the foot between 1969 and 2008. The data set included age, gender, histology grade, anatomical site of tumor, metastases, recurrence, and treatment modalities. High and low grade tumors were distinguished from each other and tumor volume was determined by imaging modalities. Delay in diagnosis was defined as the first clinical symptom to the histological diagnosis by biopsy. Inadequate treatment was defined as intralesional resections. Adequate treatment for high-grade tumors was considered to be chemotherapy in Ewing and osteosarcomas, and wide or radical resection of all sarcomas. Descriptive data analysis was performed.

Results: The overall median delay in diagnosis was 10 months with Ewing sarcoma being the longest delay. Patients with a delay of over and under 12 months did not show a significant difference in 5 year survival. Patients’ five and 10 year survival rate when treated with radical resection versus other forms of excision were 87 percent versus 72 percent, and 63 percent versus 49 percent, respectively.

For a chondrosarcoma tumor, the diagnosis delay was median of 7.5 months while other anatomical locations literature showed a five to 10 month delay. Median size of a low grade chondrosarcoma was 3.1 ml and high grade was 16.7 ml. The five and 10 year survival rate for the present study was 100 percent and 86 percent respectively for low grade, and 83 percent and 66 percent respectively for high grade. When compared to other body sites, literature has shown an 89-96 percent and 89 percent five and 10 year for low grade and 53-62 percent and 38-53 percent respectively for high grade.

Osteosarcoma diagnosis time delay median was 15 months, and when found primarily in other body sites, the literature has shown a 3.5 to 6.4 month diagnosis delay. Median size for a low grade osteosarcoma was 50 ml and high grade was 14.4 ml. The five and 10 year survival rate for the osteosarcoma was 67 percent and 67 percent for low grade, and 80 percent and 60 percent respectively for high grade. When compared to other body sites, literature has shown a 66 percent five year survival rate for low grade lesions and 60-80 percent and 20-40 percent for five and 10 year for high grade lesions.

Ewing sarcoma diagnosis time delay median was 18 months, and in other body sites literature has shown a three to 9.6 month delay. The median tumor size was 50 ml. The five and 10 year survival rates for Ewing Sarcoma were 71 percent and 28 percent respectively compared to other body sites where literature has shown a 50-70 percent and 20-50 percent five to 10 year survival rate.

Conclusions This study sheds light that primary bone tumors in the foot may behave differently than those found in other body sites. The authors have shown that primary malignant bone tumors of the foot appear to grow slower and to be less aggressive than those at other anatomical locations even with the increased delay of diagnosis. The author also reports that these tumors grow approximately 10- to 20-fold slower rate than tumors at other sites of the body.

Limitations of this study include the wide range of years that the patients were studied. Technology used in the diagnosis and treatment of malignant bone tumors has changed vastly from 1969 to 2008. However, due to the relative rarity of primary malignant bone tumors in the foot, this study shows how the foot may behave differently compared to tumors in other anatomical sites in a biologic manner, and that further research is warranted on how to better diagnose and treat these affected patients.

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