Primary characteristics and outcomes of newly diagnosed low-grade endometrial stromal sarcoma

To assess potential predictive variables for nodal metastasis and survival outcomes in patients with newly diagnosed, low-grade endometrial stromal sarcoma.

We performed a single-institution, retrospective analysis of consecutive patients with newly diagnosed, low-grade endometrial stromal sarcoma who presented between January 1, 1980 and December 31, 2019 and underwent hysterectomy at our institution or presented within 3 months of primary surgery elsewhere before recurrence. Patients who presented to our institution only at recurrence were excluded. Patients with <3 months of follow-up were excluded from survival analyses.

We identified 127 consecutive patients for analysis. Median age at diagnosis was 48 years (range 19-88 years); 91 (74.6%) of 127 were pre-menopausal; and 74 (58.3%) of 127 had uterine-confined, stage I tumors. Of 56 patients (44.1%) who underwent lymph node sampling, 10 (17.9%) had nodal metastasis. Of the 10 with nodal metastasis, 1 (10%) did not have lymphadenopathy or extra-uterine disease, 4 (40%) had lymphadenopathy only, 1 (10%) had extra-uterine disease only, and 4 (40%) had both. Among the 29 patients without apparent extra-uterine disease or gross lymphadenopathy, there was one occult lymph node metastasis (3.4%). Gross lymphadenopathy at time of surgery was predictive for lymph node metastasis (p<0.001). Median follow-up was 69 months (range 4-336) for the 95 patients included in the survival analyses. The 5-year progression-free survival and disease-specific survival rates were 79.8% and 90.8%, respectively. Patients with stage I tumors had longer progression-free survival than those with stage II-IV disease (p<0.001); there was no difference in disease-specific survival (p=0.63). Post-operative observation versus adjuvant therapy with hormone blockade or radiation therapy did not result in progression-free survival differences for stage I or completely resected stage II-IV disease (p=0.50 and p=0.81, respectively). Similarly, there was no disease-specific survival difference for completely resected stage II-IV disease (p=0.3).

Lymph node dissection in patients with low-grade endometrial stromal sarcoma should be reserved for those with clinically suspicious lymphadenopathy. Disease stage correlated with progression-free survival but not disease-specific survival. Post-operative therapy did not improve progression-free survival or disease-specific survival.