Increased survival in non-endometrioid endometrial cancer after introducing lymphadenectomy and tailoring radiotherapy - A population-based cohort study.

OBJECTIVE

To investigate recurrence and survival in non-endometrioid endometrial cancer in a population-based cohort and evaluate the implementation of the first national guidelines (NGEC) recommending pelvic and paraaortic lymphadenectomy for surgical staging and tailored adjuvant therapy.

METHODS

A population-based cohort study that used the Swedish quality registry for gynaecological cancer for the identification of all women with early-stage non-endometrioid endometrial cancer between 2010 and 2017. Five-year overall (OS) and disease-free survival (DFS) were calculated using the Kaplan-Meier method. The Cox proportional hazards regression model was used to evaluate the effect of age, FIGO stage, primary treatment and lymph node dissection on DFS.

RESULTS

There were 228 patients included in the study cohort and 67 (29%) patients had a recurrence within five years. In the recurrence cohort, the OS was 13.4% (95%CI:7.3-24.7) compared to 88.5% (95%CI:83.4-93.9) if no recurrence occurred (log-rank p < 0.001). The DFS for the complete cohort was 61.9% (95%CI:55.7-68.7). The OS before implementation of NGEC was 57.3% (95%CI:48.2-68.1) and the DFS was 52.1% (95%CI:43.0-63.1) compared to an OS of 72.0% (95%CI:64.2-80.7; log-rank p = 0.018) and a DFS of 70.1% (95%CI:62.4-78.7; log-rank p = 0.008) after implementing NGEC. Patients received adjuvant radiotherapy in 92.7% before and 42.4% after NGEC implementation (p < 0.001). In the multivariable regression analysis, age, FIGO stage and lymph node dissection were found to be significant prognostic factors, where having a lymph node dissection decreased the risk of recurrence or death with a HR of 0.58 (95%CI:0.33-1.00).

CONCLUSION

In this population-based cohort of preoperative early-stage non-endometrioid EC, a significant improvement in survival was seen after NGEC implementation where lymph node staging for tailoring adjuvant therapy was introduced and less pelvic radiotherapy was given.