Surgery (Local Control Management)

Surgical removal of the entire tumor should be considered initially, but only if functional and cosmetic impairment will not result.[2] With that stipulation, complete gross resection of the primary tumor, with a surrounding margin of normal tissue, and biopsy are recommended by the authors of one study. For some tumor sites, sampling of regional draining lymph nodes is necessary. Children's Oncology Group (COG) protocols require regional draining node sampling in extremity tumors and paratesticular tumors in patients older than 10 years. Important exceptions to achieving an R0 resection (negative margins) are in tumors of the orbit and the genitourinary region.[3,4] Additionally, the principle of wide and complete resection of the primary tumor is less applicable for patients known to have metastatic disease at the initial operation, but it is an appropriate approach if easily accomplished without loss of form (cosmesis) and function.

Patients with microscopic residual tumor after their initial surgery appear to have improved prognoses if a second operation (primary re-excision) to resect the primary tumor bed before beginning chemotherapy can completely remove the tumor without loss of form and function.[5]

There is no evidence that debulking surgery (i.e., surgery that is expected to leave macroscopic residual tumor) improves outcomes, compared with biopsy alone; therefore, debulking surgery is not recommended for patients with rhabdomyosarcoma.[6][Level of evidence B4] Rather than debulking a tumor at the time of initial biopsy, it is preferable to delay definitive surgery until after induction chemotherapy (delayed primary excision). In a retrospective study of 73 selected patients, delayed primary excision allowed for the identification of viable tumor that remained after initial chemotherapy. Of the 73 patients, 65 also received RT. Patients with viable tumor had shorter event-free survival (EFS) rates than did patients without viable tumor, but there was no effect on overall survival (OS).[7] There is also no evidence that performing surgical resection on residual masses detected by imaging at completion of all planned therapy improves outcomes.[8] Thus, residual masses can be monitored without therapeutic intervention.

For children with low-risk rhabdomyosarcoma, local control was not diminished with reduced doses of RT after surgical resection.[9] Subsequently, delayed primary excision was evaluated by the Soft Tissue Sarcoma Committee of the COG (COG-STS) in the D9602 and D9803 studies.[8] Delayed primary excision at week 12 after induction chemotherapy was completed in 45% to 54% of patients with Group III rhabdomyosarcoma tumors when appropriate (anticipated complete resection with no loss of form or function at select sites such as bladder, prostrate, extremity, trunk, retroperitoneum, intrathoracic, perineum, or perianal). Of these patients, 81% to 84% were eligible for modest RT dose reduction. Approximately 50% of these patients had an R0 resection (negative margins) and received a reduced RT dose of 36 Gy, and 30% of patients had an R1 resection (margins were microscopically involved) and received a reduced RT dose of 41.4 Gy (from the standard 50.4-Gy dose). Local control and survival outcomes were similar to those of patients who received full-dose RT alone in the IRS-IV study.[7]

A retrospective analysis compared patients with clinical Group III rhabdomyosarcoma treated on consecutive COG protocols D9803 (encouraged delayed primary excision) and ARST0531 (NCT00354835) (discouraged delayed primary excision).[10] Among 369 patients in an adjusted-regression analysis, the risk of death (hazard ratio [HR], 0.71; 95% confidence interval [CI], 0.43–1.16) was similar for patients who did or did not undergo delayed primary excision. A subset of patients who had tumors of the trunk and retroperitoneum did have a reduced risk of death with delayed primary excision (HR, 0.44; 95% CI, 0.20–0.97).