Postoperative radiation boost does not improve local recurrence rates in extremity soft tissue sarcomas

Abstract

Introduction: The standard of care for extremity soft tissue sarcomas continues to be negative-margin limb salvage surgery. Radiotherapy is frequently used as an adjunct to decrease local recurrence. No differences in survival have been found between preoperative and postoperative radiotherapy regimens. However, it is uncertain if the use of a postoperative boost in addition to preoperative radiotherapy reduces local recurrence rates. Methods: This retrospective review evaluated patients who received preoperative radiotherapy (n = 49) and patients who received preoperative radiotherapy with a postoperative boost (n = 45). The primary endpoint analysed was local recurrence, with distant metastasis and death due to sarcoma analysed as secondary endpoints. Wilcoxon rank-sum test and either χ2or Fisher's exact test were used to compare variables. Multivariable regression analyses were used to take into account potential confounders and identify variables that affected outcomes. Results: No differences in the proportion or rate of local recurrence, distant metastasis or death due to sarcoma were observed between the two groups (P > 0.05). The two groups were similarly matched with respect to demographics such as age, race and sex and tumour characteristics including excision status, tumour site, size, depth, grade, American Joint Committee on Cancer stage, chemotherapy receipt and histological subtype (P > 0.05). The postoperative boost group had a larger proportion of patients with positive microscopic margins (62% vs 10%; P < 0.001). Conclusion: No differences in rates of local recurrence, distant metastasis or death due to sarcoma were found in patients who received both pre- and postoperative radiotherapy when compared with those who received only preoperative radiotherapy.