Background: The aim of this study was to assess prognostic factors and implications on further management in a large series of stage-II or III Atypical Proliferative Serous Tumors (APST) with a long-term follow-up.
Patients and methods: Patients with APSTs and peritoneal implants treated in, or referred to, our institution were retrospectively reviewed. Prognostic factors on invasive recurrence, disease-free (DFS) and overall survival (OS) were analyzed.
Results: Between 1971 and 2017, 212 patients were identified and followed (33 having invasive implants). After a median follow-up of 115 months, 70 recurrences were observed, 28 of them under the form of invasive disease. DFS at 5 years and 10 years was 73% and 62% respectively. The use of a conservative treatment (HR = 5.5[3.33-9.08], p < .0001), the presence of ≥3 peritoneal sites with implants (HR = 1.65[1.01-2.72], p = .045) were unfavorable prognostic factors for DFS. The presence of ≥3 peritoneal sites with implants (HR = 3.02[0.96-9.53], p = .049) and the presence of stromal microinvasion (HR = 3.19[1.12-9.1], p = .022) were unfavorable prognostic factors for OS. Non-conservative surgery (HR = 7[2.35-20.87], p = .0002), invasive implants (HR = 5.37[1.29-22.26], p = .013), and ≥ 3 peritoneal sites with implants (HR = 3.56 [1.11-11.39], p = .024) were identified as predictors of recurrence in the form of an invasive disease. Invasive implants were not associated with DFS (HR = 1.39[0.77-2.51], p = .27), nor OS (HR = 1.76[0.57-5.47], p = .32).
Conclusion: After a long-term follow-up, type of peritoneal implants is no longer a prognostic factor for OS. Implants ≥3 peritoneal sites seem to impact significantly OS and then require a specific follow-up in this subgroup of patients.
Keywords: Atypical proliferative serous tumor; Extraovarian low-grade serous carcinoma; Invasive implants; Noninvasive implants; Ovary.
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