Definitive Local Therapy in cM1 Major Salivary Gland Cancer

Area of Science:

• Oncology
• Head and Neck Surgery
• Radiation Oncology

Background:

• Major salivary gland cancers (MSGC) are rare, and treatment outcomes for clinically distantly metastatic (cM1) disease remain challenging.
• Optimal management strategies for cM1 MSGC are not well-defined, necessitating investigation into the role of local therapies.

Purpose of the Study:

• To evaluate the impact of surgical resection and radiotherapy on overall survival (OS) in patients with cM1 MSGC.
• To compare the effectiveness of various treatment modalities, including chemotherapy alone, chemoradiotherapy (CRT), and surgical resection plus chemotherapy or CRT.

Main Methods:

• Retrospective cohort study utilizing the National Cancer Database (2006-2020).
• Analysis included 700 patients with cM1 MSGC treated with chemotherapy, comparing outcomes for chemotherapy alone, low-dose CRT, high-dose CRT, and combinations with surgical resection.
• Kaplan-Meier and multivariable Cox regression models were employed to assess overall survival.

Main Results:

• High-dose CRT (5-year OS 34%) and surgical resection plus high-dose CRT (5-year OS 28%) were associated with significantly higher OS compared to chemotherapy alone (5-year OS 10%).
• Surgical resection combined with chemotherapy (aHR 0.67) and high-dose CRT (aHR 0.55) were independently associated with improved OS.
• Immunotherapy also showed a significant survival benefit (aHR 0.49).

Conclusions:

• A minority of cM1 MSGC patients received surgical resection or high-dose CRT, despite potential survival benefits.
• High-dose CRT was associated with the highest overall survival, indicating its potential as a definitive local therapy.
• Surgical resection, even with a high rate of distant metastasis at presentation, was linked to improved OS compared to chemotherapy alone, suggesting a role for definitive local treatment in select cases.