Lymph node metastases as only qualifier for stage IV serous ovarian cancer confers longer survival than other sites of distant disease - a Swedish Gynecologic Cancer Group (SweGCG) study

Background: The International Federation of Gynecology and Obstetrics (FIGO) ovarian cancer staging system includes no sub-stage for lymph nodes (LN) as only distant disease manifestation. We explore the prognostic implication of LN as only stage IV classifier in serous ovarian cancer.Method: This is a nation-wide, population-based study on 551 women with serous stage IV cancers diagnosed between 2009-2014. We compare overall survival (OS) in women with LN as only distant metastatic site to those with pleural metastases only and to patients with other/multiple stage IV manifestations. Cox regression models were used for uni- and multivariable estimations.Results: Of 551stage IV cases, distant metastatic site was registered in 433. Median OS for women with LN (n=51) was 41.4 months, compared to 25.2 and 26.8 months for patients with pleural (n=195) or other/multiple (n=187) distant metastases (p=.0007). The corresponding five-year survival rates were 32, 11 and 22%, respectively. Multivariable analyzes confirmed shorter survival for women with pleural (HR 2.99, p=.001) or other/multiple distant sites (HR 2.67, p=.007), as compared to LN cases. LN only patients lived 9.1 months longer after primary than after interval surgery, but this difference was not significant (p=.245).Conclusion: Women with stage IV serous ovarian cancer having lymph nodes as only distant metastatic site live longer than other stage IV patients.