OncoLink Scientific Meetings Coverage   /   ASCO   /   OncoLink at ASCO 2004   /   Tuesday, June 8, 2004

Proton beam therapy for bone and soft tissue sarcomas: 35-year single institutional retrospective review

Reporter: John P. Plastaras, MD, PhD
Abramson Cancer Center of the University of Pennsylvania
Last Modified: October 13, 2006

Presenter: S. Goldberg
Affiliation: Harvard Medical School, Mass General Hospital, Boston, MA
Other Authors: A. Agarwal, T. DeLaney, M. Niemerko, A. Niemerko, H. Suit

Background

• Bone and soft tissue extremity sarcoma is usually treated with a combination of surgery and radiation
• Proton radiation has been used post-operatively in selected cases at MGH since 1971.

Material and Methods

• This is a retrospective, single institutional review of sarcomas treated with proton radiotherapy
• 216 patients with primary soft tissue sarcoma were treated with protons between January 1971 and December 2005
• The following variables were reviewed:
  • anatomical site, size (< 5 cm or > 5 cm), grade (1-4/4), extent of surgical resection (biopsy, R2, R1, or R0), curative vs. palliative intent, gender, radiation dose, T-stage, N-stage

Results

• Median Radiation Dose:
  • Soft tissue sarcoma: 64.8 CGE
  • Bone sarcoma: 71.9 CGE (chordomas were treated with higher doses: 74.2 CGE)
• Mean follow-up: 40 months (median 60 months)
• Local failure: 33% at 5 yr and 47% at 10 yr
• Overall survival: 72% at 5 yr and 62% at 10 yr
• The only variable that was significant for local failure was size (p=0.02), and none of the other variables were significant in terms of local failure or survival

Author's Conclusions

• The local control and overall survival rates in this series are worse than what would be expected for extremity sarcomas, probably reflecting the selection of these patients for proton radiotherapy
• Smaller tumors (<5 cm) showed a statistically significantly better local control when treated with proton radiotherapy, although overall survival was the same irrespective of tumor size
• Theis long-term series represents one of the largest sarcoma experiences for patients treated with protons
• This analysis is consistent with historically identified prognostic factors

Clinical and Scientific Implications

• This retrospective review of 216 patients with sarcoma treated with proton radiotherapy will serve as a historical control for future studies
• Proton therapy is an excellent method to deliver adjuvant radiation, especially in difficult to treat areas
• It is surprising that only size fell out as an important prognostic factor. Previous studies have shown that grade, margin status, and stage correlated with local control and overall survival, and it is unclear why only size was important in this series.