Lee, Katie N.

ABSTRACT Purpose We studied histologic Ewing sarcoma (ES) tumor response at local control surgery to explore associations between histologic response and chemotherapy practice changes over time and confirm its prognostic significance in the modern era. Methods We reviewed clinical data for 126 patients with ES treated at Mayo Clinic from 1977 to 2022, analyzing the percentage necrosis as a prognostic factor across chemotherapy regimens (including modern interval‐compressed VDC‐IE). Results In the historical cohort, 5‐year event‐free survival (EFS) and overall survival (OS) for patients with ≤5% versus greater than 5% viable tumor were 76% versus 59% ( p = 0.01) and 83% versus 62% ( p = 0.01). Review of 104 specimens by two pathologists identified the percentage remaining viable tumor as more reproducible than the percentage necrosis and/or fibrosis. On multivariable analysis of patients with localized disease ( n = 87), pelvic tumors and greater than 5% viable tumor remained independent risk factors for poor survival (EFS: hazard ratio [HR] 3.1, p < 0.01; OS: HR 2.1, p = 0.048). The modern cohort consisted of 22 patients. No patients with tumor size less than 8 cm at diagnosis and 100% necrosis after surgery had events; four of seven with tumors greater than 8 cm had events despite 100% necrosis. Conclusions Our results validate the historical threshold of greater than 5% viable tumor with older chemotherapy regimens but not with modern interval‐compressed VDC‐IE. In addition, inter‐rater reliability for the percentage viable is more reproducible than the percentage necrosis. Although numbers are small, tumors less than 8 cm with no viable tumor appear to be a favorable subgroup and suggest risk stratification using a combination of tumor size and any viable tumor should be evaluated in ES.

Background: Myxofibrosarcomas are notoriously highly infiltrative soft-tissue sarcomas, making negative surgical margins difficult to obtain. Recently, vacuum-assisted closure (VAC) is used to delay wound closure until a negative margin has been achieved; however, this can delay care and increase costs. Our institution has historically performed single-stage resections with intraoperative frozen margin analysis and reconstruction in these patients. The purpose of this study is to report the outcomes of this technique. Methods: We reviewed 112 patients (62 males, mean age 70 ± 14 years) with superficial myxofibrosarcoma. Eighty-eight patients received preoperative radiation. All patients underwent surgical resection with intraoperative frozen margin analysis, and the planned reconstruction was performed in a single anesthetic. Results: The 10-year local recurrence-free survival was 90%; positive intraoperative frozen section (HR 7.44, p = 0.004) and final permanent margins (HR 8.53, p = 0.007) were associated with local recurrence. Intraoperative margins were negative in 103 (92%) of patients, 1 of which was positive on final permanent section. There were nine cases of microscopically positive margins, of which seven underwent immediate re-excision to a negative margin. The accuracy of frozen margin assessment for myxofibrosarcoma was between 92.92 and 98.23%. All patients underwent reconstruction at the time of resection, with 19% needing an additional procedure, most commonly due to a wound complication (12%). Conclusions: Multidisciplinary single-stage excision with intraoperative frozen margin assessment and soft-tissue reconstruction yields low rates of local recurrence in patients with superficial myxofibrosarcoma.

Importance: Lung cancer and pulmonary metastases remain the leading cause of cancer-related mortality. While surgery is the gold standard, local tissue-ablative therapies are increasingly used in unresectable disease or inoperable patients. Minimally invasive local control presents a safe, repeatable approach to slow disease progression and prolong survival. Observations: Ablative techniques (radiofrequency, microwave, cryoablation, pulsed electric field) utilize extreme heat, cold, or energy to induce cancer cell death. Traditionally, ablation occurred percutaneously with image guidance, but transbronchial approaches are gaining popularity due to a potentially improved complication profile with reduced tumoral seeding. Stereotactic body radiotherapy utilizes non-invasive, precise radiation with a steep dose fall-off to protect peritumoral tissue. Transarterial infusions via transarterial chemoembolization and intraarterial chemoperfusion are emerging approaches that exploit tumor vasculature to provide focal cytotoxicity and ischemia. Intratumoral injectables (chemotherapy, immunotherapy, radiosensitization, oncolytic viruses, adoptive cell therapy, and chimeric antigen receptor T-cell therapy) directly target the tumor microenvironment, potentially increasing efficacy whilst minimizing systemic adverse effects. Conclusions and relevance: In the age of individualized cancer therapy, a multidisciplinary approach with concurrent modalities can achieve local control. This review provides a comprehensive discussion regarding the role and types of local control, safety, efficacy, and survival outcomes in assessing percutaneous, transbronchial, intraarterial, and intratumoral approaches in nonsurgical patients.