Comparison of the clinical behavior of newly diagnosed stages II-IV low-grade serous carcinoma of the ovary with that of serous ovarian tumors of low malignant potential that recur as low-grade serous carcinoma

Background.: Serous ovarian tumors of low malignant potential (STLMP) frequently coexist with low-grade serous carcinoma of the ovary (LGSC) and, when they recur, frequently do so as LGSC. The purpose of this study was to compare the outcomes of patients with these two tumor types. Methods.: All patients with stages II-IV LGSC (group 1) or with STLMP that recurred as LGSC (group 2) seen at our institution from 1973 to 2003 were identified, and demographic data were obtained. For group 1, progression-free and overall survival times were calculated from the date of primary diagnosis to the date of disease progression/recurrence or the date of last contact/death, respectively. For group 2, progression-free and overall survival times were calculated from the date of first relapse as a LGSC to the date of progression or the date of last contact/death, respectively. The method of Kaplan and Meier was used to estimate survival, and the log-rank test was used to compare differences between survival curves. Results.: We identified 112 patients in group 1 and 41 in group 2. There were no statistically significant differences between the two groups in median age (42.7 vs. 45.4 years [at relapse]; P = 0.37), progression-free survival time (19.5 vs. 25 months; P = 0.92), or overall survival time (81.8 vs. 82.8 months; P = 0.84). Conclusions.: The age at diagnosis, progression-free survival time, and overall survival time associated with newly diagnosed stages II-IV LGSC of the ovary are similar to those of STLMP that recur as LGSC, providing further evidence of an association between these two tumor types.