Primary parotid lymphoma: the effect of International Prognostic Index on outcome

Since the reported survival and failure-free survival (FFS) of adults with primary parotid non-Hodgkin's lymphoma (NHL) is variable, we reviewed our experience of untreated adults with primary parotid NHL. Patients were eligible if they presented to the University of Texas M. D. Anderson Cancer Center Cancer between 1980 and 1995 with parotid enlargement and if the diagnosis of lymphoma was verified according the Working Formulation. Medical records were reviewed to determine Ann Arbor Stage (AAS), the International Prognostic Index (IPI) score, response to therapy, relapse, FFS, and survival. We identified 39 untreated adults with primary parotid NHL representing 1% of all lymphomas and 8.6% of all untreated parotid neoplasms. Three patients were excluded because of suboptimal therapy, leaving 36 patients eligible for outcome analysis. Of the 18 patients with low-grade NHL, two were treated with radiotherapy, eight with chemotherapy and radiotherapy, seven with chemotherapy only, and one with antibiotics. The complete remission (CR) rate was 94%, and with a median follow-up of 36 months for surviving patients the survival and failure-free survival (FFS) at 5 years were 94% and 78%, respectively. The 5-year FFS were not statistically different between patients with early (I or II) or advanced (III or IV) AAS (83% and 74%, respectively; p > 0.05) and favorable (0 or 1) or unfavorable (> 1) IPI scores (73% and 100%, respectively; p > 0.05). All 18 patients with intermediate-grade NHL were treated with doxorubicin-based chemotherapy which was followed by radiotherapy in six. The CR rate was 89%, and with a median follow-up of 51 months for surviving patients the survival and FFS at 10 years were 80% and 72%, respectively. In this group 10-year FFS was better in early than in advanced AAS (100% vs 0%, respectively; p = 0.01) and in favorable (0 or 1) than in unfavorable (> 1) IPI scores (86% vs 20%, respectively; p < 0.01). We conclude the the FFS of patients with low-grade NHL is 78% and not affected by AAS or IPI score. The FFS of patients with intermediate-grade NHL appears comparable with that of NHLs of other primary sites, being 86% for those with IPI < or = 1 and 20% for those with IPI 1. Patients with IPI > 1 should be entered on investigational protocols aiming to increase FFS.