Do Radiotherapy Planning Factors Influence Para-Aortic Recurrence in IIIC1 Cervical Cancer Patients?

Abstract

Patients with locally advanced cervical cancer are at higher risk of para-aortic lymph node recurrence, however, the addition of prophylactic para-aortic irradiation is still controversial. The aim of this study was to evaluate prognostic factors related to para-aortic recurrence in patients with cervical cancer and pelvic lymph node metastasis (2018 FIGO Stage IIIC1).A retrospective cohort analysis was conducted with patients with cervical cancer and pelvic lymph node metastasis (2018 FIGO Stage IIIC1), that were treated with primary or adjuvant chemoradiotherapy from 2007 to 2018 at a single tertiary cancer center. Clinical and pathological variables were evaluated, as well as radiological and radiotherapy planning factors. Kaplan-Meier method was used to calculate survival and survival comparison between groups with log-rank method. Statistically significant was defined as P ≤ 0.05.Seventy-two patients were included: 56 (77.8%) had primary chemoradiotherapy and 16 (22.2%) adjuvant chemoradiotherapy after radical hysterectomy and lymph node staging. 58 (80.5%) underwent 3D-conformal, 14 (19.5%) intensity-modulated radiotherapy, and 67 (93%) also had high dose rate vaginal brachytherapy. Only 1 patient did not receive concomitant chemotherapy. Staging PET-CT was available in 23 (31.9%) cases and the remaining ones were staged with MRI or CT scans, Surgical para-aortic staging was not performed. The median follow-up was 42 months (range, 5 to 144 months). Overall, 27 (37.5 %) patients recurred during follow-up, and 7 (26 %) had isolated para-aortic lymph-node recurrence. Distant metastasis and pelvic recurrence were found in 12 (45 %) and 8 (29 %) cases, respectively. Median overall survival, disease free survival, distant metastasis free survival, loco-regional free survival and para-aortic free survival were 56, 52, 52, 51 and 42 months, respectively. In univariate analysis, PET SUV in pelvic lymph nodes higher than 10.2 (P = 0.02) and positive lymph nodes in the left common iliac station (P = 0.05) were identified as predictive factors for isolated para-aortic recurrence. We also identified positive lymph node in the common iliac station as a predictor for distant recurrence (P = 0.002). Tumor size larger than 66 mm (P = 0.046) and positive lymph node in the left common iliac lymph node station (P = 0.02) as predictors for pelvic recurrence. Lymph node > 24 mm was the only prognostic factor associated with overall survival (P = 0.012).In this retrospective cohort, radiological and radiotherapy planning factors as high lymph node's PET SUV and proximal location of positive pelvic lymph nodes were prognostic for para-aortic recurrence in IIIC1 cervical cancer patients. Further prospective and randomized studies are required to validate those risk factors as well as to determine if prophylactic para-aortic irradiation would improve outcomes in these patients.P.J. Pinto: None. S.L. Favareto: None. C.F. Souza: None. G. Baiocchi: None. A.A. da Costa: None. A.C. Pellizon: None. C. Abrahao: None. D.G. Castro: None. G.R. Gondim: None. H. Ramos: None. E. Santos Neto: None. R.C. Fogaroli: None. M.G. Silva: None. M.J. Chen: None.