Prognostic implication of retrocrural lymph node involvement revealed by ¹⁸F-FDG PET/CT in patients with uterine cervical cancer

Objectives: Lymph node involvement in cervical cancer is an indication of poor prognosis and the risk tends to increase according to the level of lymph node involvement. However, the specific prognostic significance of retrocrural lymph node involvement has not been well characterized because of its small size and deep location. The aim of this study was to assess its prognostic value. Patients and methods: A total of 217 patients with newly diagnosed International Federation of Gynecology and Obstetrics (FIGO) stage IA2-IVA cervical cancer were retrospectively enrolled. All the patients had undergone pretreatment ¹⁸F-fluorodeoxy-D-glucose (¹⁸F-FDG) PET/CT. Of these patients 145 were treated with concurrent chemoradiotherapy, and in this group we assessed the relationship of retrocrural lymph node involvement with the risk of disease progression. Results: Retrocrural lymph node involvement was seen in 7.4% of patients (16/217). All of them had para-aortic lymph node involvement and 56% of the 16 patients (9/16) had concomitant supraclavicular lymph node involvement. In the patients treated with concurrent chemoradiotherapy it was found that the higher the level of ¹⁸F-FDG-positive lymph nodes detected in them, the worse the progression-free survival experienced by them (none vs. pelvic, pelvic vs. para-aortic, para-aortic vs. retrocrural; P<0.05); however, there was no difference in progression outcome between retrocrural and supraclavicular areas (P=NS). On multivariate Cox proportional hazard analysis, the highest level of ¹⁸F-FDG PET/CT-positive lymph nodes in the para-aortic [hazard ratio (HR) 6.05, 95% confidence interval (CI) 2.18-16.81], retrocrural (HR 17.05, 95% CI 5.34-54.44), and supraclavicular areas (HR 19.56, 95% CI 7.15-53.54) was a significant prognostic factor. Conclusion: The highest level of lymph node involvement in para-aortic, retrocrural, supraclavicular areas was a significant prognostic factor for progression in uterine cervical cancer patients who were treated with concurrent chemoradiotherapy. Retrocrural lymph node involvement shows a similar outcome with supraclavicular involvement, but leads to a worse outcome in terms of progression compared with para-aortic lymph node involvement.