Myoepithelial Carcinoma and the Role of Radiation Therapy: A Case Report and Analysis of Data from the Surveillance, Epidemiology, and End Results (SEER) Registry

Abstract

comparison of characteristics between the two groups. Survival estimates were calculated using the Kaplan-Meier method. Results: A total of 124 lesions (56 for CHRT and 68 for SBRT) were treated in 46 patients. Median follow-up was 32 months (28.5 for SBRT vs. 37.5 for CHRT; pZ0.11). Median age at treatment was 59.5 and 53 years for SBRT and CHRT, respectively (pZ0.04). SBRT-treated patients had higher rates of oligometastasis (72% vs. 52%, pZ0.02) and more had all of their known lesions treated (65% vs. 22%, p<0.0001). Most common regimens were 3000 cGy in 10 fractions (CHRT) and 5000 cGy in 5 fractions (SBRT). Treatment intent was curative for 66% in the SBRT group. More patients treated with CHRT received chemotherapy (55% vs. 27%, pZ0.002). However, more patients treated with SBRT received immunotherapy (70% vs. 41%, pZ0.005). LC was higher with SBRT (91% vs. 67%, pZ0.009), as was the complete response rate (81% vs. 13%, p<0.0001). Median PFS was 112 days for SBRT and 47 days for CHRT (pZ0.001). Six and 12-month PFS were 35% and 15% for SBRT and 9% and 7% for CHRT (pZ0.001). Median OS was higher after SBRT (22.9 months vs. 6.9 months, p<0.0001). One and 2-year OS were 71% and 49% for SBRT and 29% and 12% for CFRT (p<0.0001). On multivariate analysis, use of SBRT (HR 0.62, pZ0.0395) and treating all lesions (HR 0.41, pZ0.005) were associated with improved PFS. On multivariate analysis for OS, age >55 years (HR 2.35, pZ0.0008), use of SBRT (HR 0.35, pZ0.0003) and treating all lesions (HR 0.22, p<0.0001) were statistically significant. In contrast, systemic therapy (chemotherapy or immunotherapy) was not associated with improved PFS or OS on multivariate analyses. Conclusion: In summary, the superior LC achieved with SBRT for extracranial MM metastases is consistent with those observed with SRS for intracranial metastases, which implies that a high biological dose can overcome the radioresistance of MM histology. Our retrospective study suggests that SBRT treatment in a select cohort of oligometastatic MM patients can lead to improvement in PFS and OS, which is consistent with surgical literature.

Combination chemotherapy of doxorubicin and ifosfamide with proton beam therapy for myoepithelial carcinoma originating in the paraspinal region: A case report and literature review

“…According to a literature review of soft tissue MECs, 19 of 58 patients (32.8%) were treated with RT as initial therapy (8). An analysis of the Surveillance, Epidemiology, and End Results (SEER) registry data showed an overall survival benefit with adjuvant RT in high-grade MEC cases (9). However, to our knowledge, there has been only 1 reported case in which ion beam RT was used for MEC (10).…”

Myoepithelial Carcinoma Arising in a Plasmacytoid Myoepithelioma of the Parotid Gland Synchronized with Melanoma: A Case Report and Review of the Literature

“…The efficacy of adjuvant therapy has been assessed in case reports and small retrospective studies [41, 57]. Radiotherapy is used as an initial therapy if surgery is contraindicated, or as adjuvant therapy if a high risk of recurrence or metastasis is perceived, such as perineural invasion or vascular embolism.…”

“…In a retrospective analysis that included 92 postoperative patients with myoepithelial carcinoma, adjuvant radiotherapy demonstrated an impact on overall survival in high-grade (III or IV) patients, with statistical significance [57]. Likewise, in another retrospective study conducted in China, 23 patients were assessed, of whom 18 underwent surgery and 9 received adjuvant radiotherapy (50–60 Gy).…”