Higher Ki67 index, nodal involvement and invasive growth were high risk factors for worse prognosis in conventional mammary analogue secretory carcinoma

Publication date: Available online 15 January 2019

Source: Journal of Oral and Maxillofacial Surgery

Author(s): Jingjing Sun, Lizhen Wang, Zhen Tian, Yuhua Hu, Ronghui Xia, Jiang Li

Abstract

Purpose

The prognostic factors of salivary (mammary analogue) secretory carcinoma (SC) are unclear because of the rarity of the tumor. Here we presented the largest case series to investigate the prognosis-related clinicopathological factors in conventional SC.

Methods

The study was based on a retrospective cohort study from 1993 to 2015 on patients whose sections were reviewed and newly diagnosed as SC by the detection of ETV6 rearrangement. The clinicopathological features including age, gender, involvement site, T category, N category, histopathological subtype, cellular atypia, tumor necrosis, growth pattern (non-invasive vs. invasive), perineural invasion, margin, hyalinized fibrous septa, Ki67 expression, and postoperative treatment were analysed as the primary predictors. Patients' final outcome--including no evidence of disease, recurrence, metastasis and death--were collected through follow-up. Survival analysis was only performed in conventional SC by using the Kaplan-Meier method and Cox proportional hazards regression model.

Results

Sixty-two cases of SC were retrospectively confirmed. Fifty-nine cases were identified as conventional SC, while an additional 3 cases were high-grade SC. In conventional SC, univariate analyses showed that nodal metastasis, invasive growth and Ki67 index ≥10% were related to lower recurrence-free survival (RFS), distant disease-free survival (DDFS) and disease-free survival (DFS). Age＞44 years, T3/T4 stage, and markedly hyalinized fibrous septa were associated with lower DDFS. T3/T4 stage, positive margins and tumor necrosis were associated with decreased OS. By multivariate analysis, the Ki67 index was found to be an independent prognostic factor for RFS (p = 0.008) and DFS (p = 0.003).

Conclusion

Although most conventional SC had favourable clinical procedure, patients with nodal involvement, invasive growth, and Ki67 index over 10% showed poor clinical outcome exhibiting local recurrence and/or distal metastasis. Patients with higher Ki67 especially need close observation for local recurrence.

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