Systematic Review of Parotid Gland Sarcomas: Multi-Variate Analysis of Clinicopathologic Findings, Therapeutic Approaches and Oncological Outcomes That Affect Survival Rate

Razionale Sarcomas represent a heterogeneous group of neoplasms that usually arise from soft or bone tissues. Sarcomas in the salivary glands are extremely rare and, in the literature, there are mainly case reports and some case series. The aim of this study was to perform a systematic review in order to evaluate the histological subtypes, therapeutic strategies and the main factors influencing oncological outcomes. Materiali e Metodi A systematic literature review was performed in MEDLINE, EMBASE, PubMed, and Scopus using combinations of the following terms: “sarcoma” OR “malignant mesenchymal tumor” OR “soft tissue tumor” OR “mesenchymal tumor” AND “parotid gland”. Inclusion criteria: demographic characteristics, sarcoma histology, tumor site, TNM, treatment, oncological outcome at the end of follow-up. A total of 307 papers were evaluated and 61 were selected. Descriptive analysis of the results was performed. Survival rate were estimated by Kaplan-Meier curves and multilinear regression were performed to identify the factors that most influence the oncological outcomes. Risultati A total of 88 patients (48 male, 40 females, mean age 39.4 years) were included. The most frequent presenting symptom is a swelling of the parotid region, followed by trismus, and paralysis of the VII n.c. In 55.7% of cases the tumor involved only the superficial lobe and in 23.9% both lobes. Clinical staging at onset was: T1 in 10,2% of cases, T2 in 31,8%, T3 in 27,3%, T4 in 30,7%. Nodal involvement was reported in 7 cases and distant metastasis in 6. Nineteen different types of histological diagnosis were observed. The most common were Rhabdomyosarcoma (21) and Synovial Sarcoma (10). The main modality of treatment for this tumor was total parotidectomy 45,5%, superficial parotidectomy 31,2% and radical parotidectomy 23,4%. Adjuvant therapies after surgical treatment were: radiotherapy in 49,1% of cases, radio-chemotherapy in 43,4%, and only chemotherapy in 7,5%. The Overall Survival (OS) was 52% at 5 years and 34.1% at 10 years. The OS for T1 stage tumor at 5 years of follow-up was 80.0%, while for T2, T3 and T4 at 5 years were 66.5%, 56.7% and 33.3%, respectively. Multivariate analysis showed that surgery (total or radical parotidectomy) performed on the tumor (p = 0.0008) was the only parameter that significantly affected the OS. Among the other variables, age (younger), use of adjuvant therapy and lymph node metastasis showed borderline significative values (p = 0.05). Conclusioni Our analysis suggests that, when a primitive parotid sarcoma is diagnosed, total or radical parotidectomy should be performed at any age independent of tumor histology. Because regional lymph node metastases from parotid sarcomas are uncommon, alternative strategies (e.g., close follow-up by imaging and evaluation of sentinel lymph nodes) should be pursued before lymph node (selective/radical) dissection.