The role of vaginal cytology in diagnosing isolated recurrence in the vaginal wall in patients with endometrial cancer with no history of radiation therapy- a retrospective multicenter observational study

Vaginal cytology is considered inappropriate for the surveillance of endometrial cancer following initial treatment. However, only a few studies have performed detailed comparisons between cytology and pelvic examinations (including bimanual and visual examinations), which are considered to be of equivalent importance. Here, we aimed to examine the clinical characteristics of cases with isolated vaginal recurrence and the effectiveness of cytology in diagnosing recurrence. We collected clinical data from institutions affiliated with the Tohoku Gynocological Cancer Unit (TGCU) on patients with endometrial cancer who had not received postoperative radiation therapy, and who experienced recurrence limited to the vaginal wall. We analyzed the diagnostic methods that led to the diagnosis of vaginal wall recurrence (vaginal cytology or other methods), its correlation with the results of pelvic examination, and its impact on prognosis following recurrence treatment. A total of 46 patients who underwent initial surgery were identified, none of whom received radiotherapy as adjuvant therapy. The median time from initial surgery to recurrence was 18 months (range: 4–120 months), with a significantly shorter time to recurrence in cases with primary tumors with an aggressive histological type (endometrioid carcinoma G3, serous carcinoma, carcinosarcoma, etc.) ( n = 23) than those with a non-aggressive histological type (endometrioid carcinoma G1 and G2) ( n = 23). Cytology results were the basis for the diagnosis of vaginal wall recurrence in 17/46 (37%) cases, including 3/17 (17.6%) symptomatic cases, and 14/29 (48.3%) asymptomatic cases ( p < 0.05). The overall survival (OS) rate (5-year survival rate, median) was 66.8% (median: Not Reached (N.R.)), and cytology as the trigger for diagnosis was not associated with prognosis. Our results suggest that cytology can serve as a trigger for diagnosing recurrent endometrial cancer confined to the vaginal wall in patients with no history of radiation therapy, particularly in cases where recurrence cannot be detected by pelvic examination.