Interval between surgery and radiotherapy: Effect on local control of soft tissue sarcoma

Purpose To evaluate the clinical significance of the interval between surgery and postoperative radiotherapy (RT) for patients with soft tissue sarcoma. Methods and materials The records of 799 patients who underwent postoperative RT for soft tissue sarcoma between 1960 and 2000 were retrospectively reviewed. Univariate and multivariate analyses were used to evaluate the potential impact of the timing of postoperative RT on the rate of local control (LC). Results The actuarial overall LC rate was 79% at 10 years and 78% at 15 years. Univariate analysis indicated that the factors associated with an inferior 10-year LC rate were positive resection margins (p <0.0001) ; treatment for recurrent disease (p <0.0001); primary location in the head and neck or deep trunk (p <0.0001); age >64 years (p <0.0001); histopathologic subtype of malignant fibrous histiocytoma, neurogenic sarcoma, or epithelioid sarcoma (p = 0.01); tumor size >10 cm (p = 0.02); postoperative radiation dose <64 Gy (p = 0.03); and high histologic grade (p = 0.05). On multivariate analysis, all these factors remained statistically significant, except for high histologic grade and large size. A delay between surgery and the start of RT of >30 days was associated with a decreased 10-year LC rate, but this association was not statistically significant (76% vs. 83%, p = 0.07). The potential association between RT delay and inferior LC could be explained by an imbalance in the distribution of other prognostic factors. Conclusion The interval between surgery and RT did not significantly impact the 10-year LC rate. These findings indicate that an RT delay should not be viewed as an independent adverse factor for LC and that treatment intensification may not be necessary for patients in whom a treatment delay has already occurred.