Low-grade serous ovarian cancer (LGSOC) represents an uncommon histotype of serous ovarian cancer (accounting for approximately 5% of all ovarian cancer) with a distinct behavior compared to its high-grade serous counterpart, characterized by a better prognosis and low response rate to chemotherapeutic agents. Similar to high-grade serous ovarian cancer, cytoreductive surgery is considered crucial for patient survival. This retrospective study aimed to analyze the outcomes of women affected by advanced stages (III–IV FIGO) of LGSOC from two high-volume oncological centers for ovarian neoplasm. In particular, we sought to evaluate the impact on survival outcomes of optimal cytoreductive surgery [i.e., residual disease (RD) <10 mm at the end of surgery]. The results of our work confirm the role of complete cytoreduction (i.e., no evidence of disease after surgery) in the survival of patients and even the positive prognostic role of a minimal RD (i.e., <10 mm), whenever complete cytoreduction cannot be achieved.

Low-grade serous ovarian cancer (LGSOC) is a rare entity with different behavior compared to high-grade serous (HGSOC). Because of its general low chemosensitivity, complete cytoreductive surgery with no residual disease is crucial in advanced stage LGSOC. We evaluated the impact of optimal cytoreduction on survival outcome both at first diagnosis and at recurrence.

We retrospectively studied consecutive patients diagnosed with advanced LGSOCs who underwent cytoreductive surgery in two oncological centers from January 1994 to December 2018. Survival curves were estimated by the Kaplan–Meier method, and 95% confidence intervals (95% CI) were estimated using the Greenwood formula.

A total of 92 patients were included (median age was 47 years, IQR 35–64). The median overall survival (OS) was 142.3 months in patients with no residual disease (RD), 86.4 months for RD 1–10 mm and 35.2 months for RD >10 mm (p = 0.002). Progression-free survival (PFS) was inversely related to RD after primary cytoreductive surgery (RD = 0 vs RD = 1–10 mm vs RD >10 mm, p = 0.002). On multivariate analysis, RD 1–10 mm (HR = 2.30, 95% CI 1.30–4.06, p = 0.004), RD >10 mm (HR = 3.89, 95% CI 1.92–7.88, p = 0.0004), FIGO stage IV (p = 0.001), and neoadjuvant chemotherapy (NACT) (p = 0.010) were independent predictors of PFS. RD >10 mm (HR = 3.13, 95% CI 1.52–6.46, p = 0.004), FIGO stage IV (p <0.0001) and NACT (p = 0.030) were significantly associated with a lower OS.

Optimal cytoreductive surgery improves survival outcomes in advanced stage LGSOCs. When complete debulking is impossible, a RD <10 mm confers better OS compared to an RD >10 mm in this setting of patients.

低级别浆液性卵巢癌 (LGSOC) 是一种不常见的浆液性卵巢癌组织型（约占所有卵巢癌的 5%），与高级别浆液性卵巢癌相比，具有不同的行为，其特点是预后较好且反应率低对化疗药物。与高级别浆液性卵巢癌类似，细胞减灭术被认为对患者生存至关重要。这项回顾性研究旨在分析来自两个高容量卵巢肿瘤肿瘤中心的受 LGSOC 晚期 (III-IV FIGO) 影响的女性的结局。特别是，我们试图评估最佳细胞减灭术对生存结果的影响[即手术结束时残留病灶 (RD) <10 mm]。我们的工作结果证实了完全细胞减灭的作用（即，

与高级别浆液性卵巢癌 (HGSOC) 相比，低级别浆液性卵巢癌 (LGSOC) 是一种具有不同行为的罕见实体。由于其一般的低化学敏感性，在晚期 LGSOC 中，没有残留疾病的完整细胞减灭术至关重要。我们评估了最佳细胞减灭术对首次诊断和复发时的生存结果的影响。

我们回顾性研究了 1994 年 1 月至 2018 年 12 月期间在两个肿瘤中心接受细胞减灭术的诊断为晚期 LGSOC 的连续患者。通过 Kaplan-Meier 方法估计生存曲线，并使用 Greenwood 估计 95% 置信区间 (95% CI)公式。

共纳入 92 名患者（中位年龄为 47 岁，IQR 35-64）。无残留疾病 (RD) 患者的中位总生存期 (OS) 为 142.3 个月，RD 1-10 mm 为 86.4 个月，RD > 10 mm 为 35.2 个月 (p = 0.002)。无进展生存期 (PFS) 与初次细胞减灭手术后的 RD 呈负相关（RD = 0 vs RD = 1-10 mm vs RD >10 mm，p = 0.002）。在多变量分析中，RD 1–10 mm (HR = 2.30, 95% CI 1.30–4.06, p = 0.004), RD >10 mm (HR = 3.89, 95% CI 1.92–7.88, p = 0.0004)，FIGO IV 期(p = 0.001) 和新辅助化疗 (NACT) (p = 0.010) 是 PFS 的独立预测因素。RD >10 mm (HR = 3.13, 95% CI 1.52–6.46, p = 0.004)、FIGO IV 期 (p <0.0001) 和 NACT (p = 0.030) 与较低的 OS 显着相关。

最佳细胞减灭术可改善晚期 LGSOC 的生存结果s. 当完全减瘤不可能时，在这种情况下，RD <10 mm 与 RD > 10 mm 相比，可提供更好的 OS。