Initial Treatment Strategies Show No Survival Difference in Early-Stage Salivary Gland Mucosa-Associated Lymphoid Tissue Lymphoma.

Abstract

Purpose: Given the indolent nature of mucosa-associated lymphoid tissue (MALT) lymphoma, immediate intervention is not always necessary, and a consensus on the optimal treatment modality remains elusive. This study aimed to evaluate survival outcomes of different initial treatments for early-stage (stage I-II) salivary gland MALT lymphoma.

Methods: Using data from the Surveillance, Epidemiology, and End Results program, we included patients diagnosed between 2000 to 2021. Initial treatments included surgery alone, radiotherapy alone, surgery combined with radiotherapy, chemotherapy alone, or observation. The chi-square test, Kaplan-Meier method, and multivariate Cox proportional-hazards models were used for statistical analyses.

Results: A total of 892 patients were included. Tumor location was known for 859 patients, with 740 (86.1%) located in the parotid gland, 116 (13.5%) in the submandibular gland, and 3 (0.3%) in the sublingual gland. Of the patients, 237 (26.6%) underwent surgery alone, 202 (22.6%) received radiotherapy alone, 170 (19.1%) underwent surgery combined with radiotherapy, 53 (5.9%) received chemotherapy alone, and 230 (25.8%) with observation. Submandibular gland tumor patients were more likely to receive radiotherapy alone, chemotherapy alone, or observation, while parotid gland tumor patients preferred surgery or surgery combined with radiotherapy (P<0.001). Over time, the proportion of observation cases increased (P=0.004). The median follow-up time was 92 months. The 8-year cancer-specific survival rates for patients undergoing surgery alone, radiotherapy alone, surgery combined with radiotherapy, chemotherapy alone, and observation were 96.1%, 94.9%, 97.0%, 92.1%, and 95.5%, respectively (P=0.827). The 8-year OS rates for these groups were 79.7%, 84.5%, 86.3%, 77.7%, and 79.5%, respectively (P=0.132). Multivariate analysis showed that initial treatment modality did not significantly affect survival outcomes. Sensitivity analyses also showed similar outcomes for the five treatment groups across different subgroups. Age and gender were independent prognostic factors associated with survival outcomes.

Conclusion: Our study highlights that early-stage salivary gland MALT lymphoma is characterized by a female predominance and an increasing trend toward observation as a management strategy. The lack of significant survival differences across treatment modalities suggests that the choice of initial treatment may be less critical than patient-specific factors such as age and gender. These findings advocate for personalized treatment approaches and underscore the importance of further research to better understand the underlying mechanisms driving gender disparities and the long-term outcomes of conservative management strategies.