Yukiko Taga

Possible overestimation of treatment effects of pelvic and para-aortic lymphadenectomy for early-stage ovarian clear cell carcinoma: a retrospective propensity-score weighted multi-center cohort study

The treatment effects of lymphadenectomy in early-stage ovarian clear cell carcinoma (OCCC) reported in previous studies may have been overestimated owing to confounding factors. This study aimed to investigate the treatment effect of pelvic and para-aortic lymphadenectomy (PeNPAN) in early-stage OCCC, with careful adjustment for potential confounders. This retrospective multi-center cohort study involved women with preoperatively suspected stage I OCCC. We included patients who underwent surgery for OCCC between 2005 and 2019 at 11 affiliated institutions. The exposure (PeNPAN) group comprised patients who underwent PeNPAN. The primary outcome was disease-free survival (DFS). Additionally, hazard ratios (HRs) of lymphadenectomy for DFS were estimated using unadjusted and propensity score-weighted Cox regression models and biased models applied in previous studies. To identify strong confounders, we further examined factors associated with recurrence that differed between the groups. We analyzed 304 women who underwent surgery for preoperatively suspected stage I OCCC. The unadjusted HR for DFS was 0.63 (95% confidence interval [CI]=0.36-1.09; p=0.10), and the propensity-score adjusted HR was 0.82 (95% CI=0.42-1.58; p=0.55). The biased model showed a statistically significant HR of 0.59 (95% CI=0.36-1.00; p=0.048). Adhesions in the Douglas' pouch and cardiovascular disease were associated with recurrence and were more prevalent in the control group, suggesting potential confounders. After adjusting for potential confounders, the observed treatment effects of lymphadenectomy in the biased models were no longer statistically significant. Future investigations should carefully account for possible confounders, including intraoperative adhesions and comorbidities.

Comparison of postoperative adjuvant platinum-based chemotherapy and no further therapy after radical surgery in intermediate-risk early-stage cervical cancer

To identify a relatively high-risk population in postoperative intermediate-risk cervical cancer and evaluate the effect of platinum-based adjuvant chemotherapy (CT). We retrospectively reviewed the medical records of patients with stage IA2-IIA cervical cancer who had been treated with radical hysterectomy and pelvic lymphadenectomy and classified as the intermediate-risk group for recurrence by postoperative pathological examination from January 2007 to December 2018 at 3 medical centers in Japan. First, patients with intermediate-risk were stratified by histological type and the number of intermediate-risk factors (IRF; large tumor diameter, lymph vascular space invasion, and deep cervical stromal invasion) and then divided into 2 groups: high and low-risk population (estimated 5-year recurrence-free survival [RFS] rate with no further therapy [NFT] <90% and ≥90%, respectively). Second, the efficacy of CT for the high-risk population was evaluated by comparing RFS and overall survival (OS) between the patients receiving CT and those with NFT. In total, 133 patients were included in the analysis. Among patients with squamous cell carcinoma (SCC) with all IRF or those with non-SCC with 2 to 3 IRF, the 5-year estimated RFS was <90% when treated with NFT. In this population, adjuvant CT was significantly superior to NFT regarding RFS (log-rank, p=0.014), although there was no statistical difference in OS. Patients with SCC with all 3 IRFs and those with non-SCC with 2 to 3 IRFs were at high risk for recurrence. Adjuvant CT is a valid treatment option for these populations.