Gao, Zhengya

ABSTRACT Background Rhabdomyosarcoma is the most common soft tissue sarcoma in pediatrics and infants are reported to have inferior outcomes. ARST1431 recommended delayed primary excision (DPE) while discouraging radiation (RT) deviations. This analysis compared outcomes among very young and older patients in this study. Procedures Demographic and tumor characteristics were summarized using frequencies and percentages. Local failure (LF) frequency was summarized by age group, RT, and DPE status. Event‐free survival (EFS) and overall survival (OS) were estimated using the Kaplan–Meier method and compared between age groups using the log‐rank test. Results Of 296 patients, 48 (16.2%) were <24 months: 14 (4.7%) < 12 months, 34 (11.5%) 12–24 months–compared with 248 (83.8%) ≥24 months. DPE was performed in: 7 (50%), <12 months; 9 (26%), 12–24 months; 56 (22%), ≥24 months. RT was given to 9 (64%), 27 (79%), and 195 (79%) of <12, 12–24, and >24 months, respectively. LF in DPE+RT was 8.3% and 6.1%, < 24 months and ≥ 24 months, respectively, compared to 29.3% and 20.5% for RT without DPE. The 4‐year EFS did not vary: 56% (95% CI = 26.5, 86.0), 68% (95% CI = 51.2, 84.1), and 61% (95% CI = 54.2, 68.3) <12, 12–24, and >24 months old, respectively. Conclusions Outcomes in younger children are comparable to older children with local failure more common in those without DPE. Optimization of local control will be important for future studies. Trial Registration Number NCT02567435

AbstractBackgroundEmbryonal sarcoma of the liver (ESL) is a rare mesenchymal tumor most common in childhood; the optimal treatment approach is uncertain. The clinical features and outcomes of patients with ESL enrolled in a Children’s Oncology Group (COG) clinical trial that evaluated a risk‐based strategy for treating soft tissue sarcomas in patients aged <30 years were evaluated.MethodsThis subset analysis included patients with ESL enrolled in COG study ARST0332. Central review of records, pathology, and imaging confirmed the diagnosis, presenting features, and surgery extent and complications. All patients received dose‐intensive ifosfamide/doxorubicin chemotherapy, with cycle timing dependent on surgery and radiotherapy. Tumor resection occurred before study entry or after four cycles of chemotherapy; radiotherapy for residual tumor was optional.ResultsThirty‐nine eligible/evaluable patients with ESL were analyzed. All tumors were >10 cm in diameter; four were metastatic. Tumor resection was performed upfront in 23 and delayed in 16. Positive surgical margins (n = 6) and intraoperative tumor rupture (n = 6) occurred only in upfront resections. Eight patients received radiotherapy. Estimated 5‐year event‐free and overall survival were 79% (95% confidence interval [CI], 65%–93%) and 95% (95% CI, 87%–100%), respectively. Positive margins increased the local recurrence risk. One of 13 patients with documented hemorrhagic ascites and/or tumor rupture developed extrahepatic intra‐abdominal tumor recurrence.ConclusionsThe treatment strategy used in ARST0332 achieved favorable outcomes for patients with ESL despite a substantial proportion having high‐risk disease features. Deferring tumor resection until after neoadjuvant chemotherapy may decrease the risk of intraoperative tumor rupture and improve the likelihood of adequate surgical margins.

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported. ARST1321 was a phase II study designed to compare the near complete pathologic response rate after preoperative chemoradiation with/without pazopanib in children and adults with intermediate-/high-risk chemotherapy-sensitive body wall/extremity non-Rhabdomyosarcoma Soft Tissue Sarcoma (ClinicalTrials.gov identifier: NCT02180867 ). Enrollment was stopped early following a predetermined interim analysis that found the rate of near complete pathologic response to be significantly greater with the addition of pazopanib. As a planned secondary aim of the study, the outcome data for this cohort were analyzed. Eight-five eligible patients were randomly assigned to receive (regimen A) or not receive (regimen B) pazopanib in combination with ifosfamide and doxorubicin + preoperative radiotherapy followed by primary resection at week 13 and then further chemotherapy at week 25. As of December 31, 2021, at a median survivor follow-up of 3.3 years (range, 0.1-5.8 years), the 3-year event-free survival for all patients in the intent-to-treat analysis was 52.5% (95% CI, 34.8 to 70.2) for regimen A and 50.6% (95% CI, 32 to 69.2) for regimen B ( P = .8677, log-rank test); the 3-year overall survival was 75.7% (95% CI, 59.7 to 91.7) for regimen A and 65.4% (95% CI, 48.1 to 82.7) for regimen B ( P = .1919, log-rank test). Although the rate of near complete pathologic response was significantly greater with the addition of pazopanib, outcomes were not statistically significantly different between the two regimens.

11504 Background: Pazopanib is a multi-targeted tyrosine kinase inhibitor (TKI) with activity in advanced soft tissue sarcoma. ARST1321 was a phase II study designed to compare the near complete pathologic response rate (≥ 90% necrosis) following preoperative chemoradiation +/- pazopanib in children and adults with intermediate/high risk chemotherapy-sensitive body wall/extremity NRSTS. Enrollment was stopped early following a predetermined interim analysis that found the rate of near complete pathologic response to be significantly greater with the addition of pazopanib. As a planned secondary analysis of the study, we now report the outcome data for this cohort. Methods: ARST1321 was a jointly designed COG and NRG Oncology study open to enrollment July 2014-October 2018. Eligible adult (≥18 years) and pediatric (< 18 years) patients with newly-diagnosed unresected body wall/extremity NRSTS were enrolled into the Chemotherapy Cohort (> 5 cm, FNCLCC grade 2/3, protocol-designated chemotherapy-sensitive histology). Following a dose-finding phase, patients were randomized to receive (Regimen A) or not receive (Regimen B) pazopanib (< 18 years: 350 mg/m2/day; ≥ 18 years: 600 mg/day) in combination with ifosfamide (7.5 gm/m2/cycle) and doxorubicin (75 mg/m2/cycle) + 45 Gy preoperative RT followed by primary resection at week 13, then further chemotherapy to week 25. Results: Eighty-five eligible patients were enrolled in the Chemotherapy Cohort and randomized to receive or not receive pazopanib. Median age 22.1 years (range: 5.7-64.2 years); 30 patients < 18 years. Most common histologies were synovial sarcoma (n = 42) and undifferentiated pleomorphic sarcoma (n = 19). As of December 31, 2021, at a median survivor follow-up of 3.3 years (range: 0.1 – 5.8 years), the 3-year event-free survival (EFS) for all patients in the intent-to-treat analysis was 52.5% (95% CI: 34.8%-70.2%) for Regimen A and 50.6% (32%-69.2%) for Regimen B (p = 0.8677); 3-year overall survival (OS) was 75.7% (59.7%-91.7%) for Regimen A and 65.4% (48.1%-82.7%) for Regimen B (p = 0.1919). Conclusions: Although the rate of near complete pathologic response was significantly greater with the addition of pazopanib to preoperative chemoradiation in children and adults with intermediate/high risk body wall/extremity NRSTS, outcomes were not statistically significantly different between the two regimens. Pathologic response could be a TKI-related phenomenon and may not be a good surrogate marker of outcome in future studies. Clinical trial information: NCT02180867.

Abstract The Children's Oncology Group (COG) uses Clinical Group (CG) and modified Tumor Node Metastasis (TNM) stage to classify rhabdomyosarcoma (RMS). CG is based on surgicopathologic findings and is determined after the completion of initial surgical procedure(s) but prior to chemotherapy and/or radiation therapy. The modified TNM stage is based on clinical and radiographic findings and is assigned prior to any treatment. These systems have evolved over several decades. We review the history, evolution, and rationale behind the current CG and modified TNM classification systems used by COG for RMS. Data from the seven most recently completed and reported frontline COG trials (D9602, D9802, D9803, ARST0331, ARST0431, ARST0531, ARST08P1) were analyzed, and confirm that CG and modified TNM stage remain relevant and useful for predicting prognosis in RMS. We propose updates based on recent data and discuss factors warranting future study to further optimize these classification systems.