Dermatofibrosarcoma protuberans (DFSP) is an uncommon soft tissue sarcoma that originates from the dermis or subcutaneous tissue in the skin. While its prognosis is generally favorable, disease recurrence is relatively frequent. Because morbidity after repeated surgery may be significant, an optimized prediction of recurrence-free survival (RFS) has the potential to improve current management strategies. The purpose of this study was to investigate the prognostic value of the Ki-67 proliferation index with respect to RFS in patients with DFSP. We retrospectively analyzed data from 45 patients with DFSP. We calculated the Ki-67 proliferation index as the percentage of immunostained nuclei among the total number of tumor cell nuclei regardless of the intensity of immunostaining. We constructed univariate and multivariate Cox proportional hazards regression models to identify predictors of RFS. Among the 45 patients included in the study, 8 developed local recurrences and 2 had lung metastases (median follow-up: 95.0 months; range: 5.2-412.4 months). The RFS rates at 60, 120, and 240 months of follow-up were 83.8%, 76.2%, and 65.3%, respectively. The median Ki-67 proliferation index was 14%. Notably, we identified the Ki-67 proliferation index as the only independent predictor for RFS in multivariate Cox proportional hazards regression analysis (hazard ratio = 1.106, 95% confidence interval = 1.019-1.200, p = 0.016). In summary, our results highlight the potential usefulness of the Ki-67 proliferation index for facilitating the identification of patients with DFSP at higher risk of developing disease recurrences.

中文翻译：

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Ki-67 增殖指数可预测隆突性皮肤纤维肉瘤患者的无复发生存率。

隆突性皮肤纤维肉瘤 (DFSP) 是一种罕见的软组织肉瘤，起源于皮肤的真皮或皮下组织。虽然其预后普遍良好，但疾病复发相对频繁。由于重复手术后的发病率可能很高，因此无复发生存期 (RFS) 的优化预测有可能改善当前的管理策略。本研究的目的是探讨 Ki-67 增殖指数对 DFSP 患者 RFS 的预后价值。我们回顾性分析了 45 名 DFSP 患者的数据。我们将 Ki-67 增殖指数计算为免疫染色细胞核在肿瘤细胞核总数中的百分比，而不管免疫染色强度如何。我们构建了单变量和多变量 Cox 比例风险回归模型来确定 RFS 的预测因子。在纳入研究的 45 名患者中，8 名发生局部复发，2 名发生肺转移（中位随访时间：95.0 个月；范围：5.2-412.4 个月）。随访 60、120 和 240 个月时的 RFS 率分别为 83.8%、76.2% 和 65.3%。Ki-67 增殖指数的中位数为 14%。值得注意的是，我们将 Ki-67 增殖指数确定为多变量 Cox 比例风险回归分析中 RFS 的唯一独立预测因子（风险比 = 1.106，95% 置信区间 = 1.019-1.200，p = 0.016）。总之，我们的结果强调了 Ki-67 增殖指数的潜在用途，有助于识别具有较高疾病复发风险的 DFSP 患者。