Long-term outcome of combined modality therapy in retroperitoneal and deep-trunk soft-tissue sarcoma: analysis of prognostic factors

Abstract

$\text{Purpose}$: To evaluate the long-term outcome of surgery and postoperative radiotherapy (RT) in retroperitoneal and deep-trunk soft-tissue sarcoma, and to identify the prognostic factors for local control, disease-free survival, and overall survival.

$\text{Methods and Materials}$: Between January 1980 and December 1998, 60 patients with nonmetastatic retroperitoneal and deep-trunk soft-tissue sarcoma were treated at Wayne State University using combined surgery and RT. The location was retroperitoneal in 38 patients (63%) and deep trunk in 22 (27%). Forty-six patients (76%) were treated for primary disease and 14 (24%) for recurrent disease. The resection margins were negative in 24 patients (40%), close in 3 (5%), and positive in 33 (55%; 18 microscopic and 15 macroscopic). The median tumor size was 8.6 cm (range 2–55). External beam RT (EBRT; median dose 5220 cGy) was given to 44 patients (73%) and combined EBRT (median dose 4200 cGy) and brachytherapy (median dose 1600 cGy) to 16 patients (27%). Univariate and multivariate Cox regression analyses were conducted to identify the possible associations between patient age, race, gender, tumor site, histologic features, grade, size, stage, surgical margin, RT dose, modality (EBRT vs. EBRT plus brachytherapy), and presentation (primary vs. recurrent) and disease control.

$\text{Results}$: The actuarial 5- and 10-year disease-free survival rate was 53% and 44%, respectively. Disease-free survival was significantly associated with female gender on univariate analysis (67% for female patients and 37% for male patients at 5 years, p = 0.05). On multivariate analysis, both gender and surgical margin had borderline significance (p = 0.06). The actuarial local control rate was 71% and 54% at 5 and 10 years, respectively. The median time to local relapse was 10.2 months, with 75% of all failures occurring within 29 months. The surgical margin status was significantly associated with local control (78% for patients with negative or close margins vs. 52% for patients with positive margins at 5 years, p = 0.04). Gender was borderline significant (85% for female patients vs. 54% for male patients at 5 years, p = 0.06). On multivariate analysis, only surgical margin status remained significant (p = 0.032). The distant metastasis-free survival rate at 5 and 10 years was 58% and 54%, respectively. The median time to distant metastases was 15.6 months. The lungs were the most common site of metastases. The only significant factor associated with distant metastasis-free survival was local control (73% for patients with locally controlled tumors vs. 19% for patients with local recurrence at 5 years, p = 0.0013). The actuarial 5- and 10-year overall survival rate was 56% and 47%, respectively. Gender (74% for female patients vs. 37% for male patients at 5 years), surgical margin status (66% for patients with negative or close margins vs. 48% for patients with positive margins at 5 years), and local control (64% for patients with locally controlled tumors vs. 21% for patients with uncontrolled primary tumors at 5 years) were significant predictors on both univariate and multivariate analyses (p <0.05).

$\text{Conclusion}$: The results of this study demonstrate the paramount importance of local control and complete surgical resection in the management of soft-tissue sarcoma of the retroperitoneum and deep trunk.