Predicting myometrial invasion using transvaginal ultrasound in reproductive-age patients with stage I endometrioid carcinoma

Despite the widespread use of transvaginal ultrasonography (TVUS) to assess the depth of myometrial invasion, its diagnostic accuracy remains limited – particularly in women with obesity and in the presence of uterine fibroids – underscoring the need for a more accurate prediction model to improve preoperative assessment and to substantiate fertility-sparing treatment in reproductive-age patients with stage I endometrioid carcinoma.

Objective: to improve the diagnostic performance for detecting myometrial invasion in reproductive-age patients with stage I endometrioid carcinoma, enabling consideration of fertility-sparing management.

Materials and methods. Analyzed 171 reproductive-age patients (24–55 years; median 46) with stage I endometrioid carcinoma who underwent evaluation – including transabdominal and transvaginal ultrasound – and surgery (pan-hysterectomy with bilateral salpingo-oophorectomy or extended hysterectomy with pelvic lymphadenectomy) at the N. N. Alexandrov Centre in 2011–2015 and 2023–2025. Operating characteristics of TVUS for detecting myometrial invasion were calculated. A multivariable predictive model was built using logistic regression with myometrial invasion as the outcome. Internal validation was performed by bootstrap resampling. ROC analysis and decision-curve (net benefit) analysis were applied. Two-sided p-values p < 0.05 were considered significant.

Results. In reproductive-age women with stage I EC and tumor grade G1–G2, myometrial invasion was significantly associated with preoperative variables: age, body mass index (BMI), tumor grade, and tumor size. We developed a multivariable model incorporating these variables together with TVUS findings to predict the probability of myometrial invasion. The model achieved an AUC of 0.821 (95 % CI 0.758–0.884; p < 0.001) and outperformed TVUS alone (DeLong p < 0.001); diagnostic sensitivity exceeded that of TVUS by 17.1 percentage points (p = 0.006). Internal validation confirmed model performance. A nomogram was constructed to graphically estimate individual probability of invasion, and decision-curve analysis demonstrated superior net benefit versus TVUS alone across threshold probabilities.

Conclusions: the proposed multivariable model significantly improves the accuracy of detecting myometrial invasion in reproductive-age patients with stage I G1–G2 endometrioid carcinoma and supports more informed selection of fertility-sparing treatment strategies.

1. GLOBOCAN 2022. Global Cancer Observatory. International Agency r Research on Cancer 2022. Cancer Today [Electronic resource]. – Access of mode: https://gco.iarc.fr/today/. – Access of date: 21.10.2024.

2. Cancer in Belarus: Figures and Facts. Analysis of data from the Belarusian Cancer Registry, 2022 / [A. E. Okeanov et al.; edited by S. L. Polyakov]. – Minsk: State Institution “Respublikanskij nauchno-prakticheskij centr onkologii i medicinskoj radiologii im. N. N. Aleksandrova”, 2024. – 280 p.

3. Clinical protocol “Algorithms for the diagnosis and treatment of malignant neoplasms” [Electronic resource]: post. Ministry of Health of the Republic. Belarus, July 6, 2018, № 60 // ETALON. Legislation of the Republic of Belarus / Nat. Center for Legal Information. Republic of Belarus. – Minsk, 2019.

4. ESMO-ESGO-ESTRO Consensus Conference on Endometrial Cancer: diagnosis, treatment and follow-up / N. Colombo [et al.] // Int. J. Gynecol. Cancer. – 2016. – Vol. 26, № 1. – P. 2–30.

5. Conservative treatment of endometrial cancer in women of reproductive age (Review) / Maria Zoi Bourou, Alkis Matsas, Thomas Vrekoussis, Georgios Mastorakos, Georgios Valsamakis, Theodoros Panoskaltsis. – May 25, 2023. – https://www.spandidos-publications.com/10.3892/mco.2023.2651.

6. Effect of bariatric surgery on endometrial cancer regression as part of fertility sparing treatment / Jinlin Lin, Weng Yan Ho, Qi Xuan Lim, Hui Xian Felicia Chin. – 2023 Jul 5. – Access of mode: https://pubmed.ncbi.nlm.nih. gov. – Access of date: 21.05.2025.

7. Endometrial Cancer Management in Young Women / Anna Markowska, Anita Chudecka-Głaz, Kazimierz Pityński, Włodzimierz Baranowski, Janina Markowska, Włodzimierz Sawicki. – 2022. – Apr 11. – Access of mode: https://pubmed.ncbi.nlm.nih.gov.

8. United Nations Population Division. World Population Prospects: 2024 Revision; ( 2 ) Statistical databases and publications from national statistical offices; ( 3 ) Eurostat: Demographic Statistics [Electronic resource]. – Access of mode: https://data.worldbank.org/indicator/SP.DYN. TFRT.IN. – Access of date: 21.05.2025.

9. National Statistical Committee of the Republic of Belarus. Interactive information and analytical system for dissemination of official statistical information [Electronic resource]. – Access of mode: https://dataportal.belstat.gov.by/osids/indicator-info/10101200011. – Access of date: 21.05.2025.

10. Demidov, V. N., Tue, A. I. Ultrasound diagnostics of hyperplastic and tumor processes of the endometrium / V. N. Demidov, A. I. Tue // Clinical guidelines for ultrasound diagnostics. – Vidar, 1997. – Vol. 3. – P. 120–131.

11. Color Doppler mapping in the diagnosis of endometrial cancer / I. N. Kapustina, A. N. Sidorova, A. N. Sarancev // Sonoace international (Russian version). – 2001. – Iss. 9. – P. 34–39.

12. Modern principles of primary and clarifying diagnostics of endometrial cancer / L. A. Ashrafyan [et al.] // Practical oncology. – 2004. – № 5(1). – P. 16–24.

13. Analysis of the results of ultrasound examination in patients with stage I endometrioid carcinoma / E. O. Ovcharova, S. A. Mavrichev, L. V. Mirilenko // Healthcare. – 2024. – № 6 (927). – P. 20–28.

14. Efficiency of transvaginal ultrasound examination in determining the depth of tumor invasion into the myometrium in patients with stage I endometrioid carcinoma / E. O. Ovcharova, S. A. Mavrichev, L. V. Mirilenko, L. V. Buglaeva [et al.] // Oncogynecology. – 2024. – № 4. – P. 25–33.

15. Zhang, Y., Li X., Zhang S. et al. Diagnostic accuracy of transvaginal ultrasound for myometrial invasion in endometrial cancer: A systematic review and meta-analysis // Ultrasound Obstet Gynecol. – 2021. – № 57(3). – Р. 492–499.

16. Epstein, E., Valentin L., Skoog L. et al. Transvaginal ultrasound versus MRI for preoperative assessment of myometrial invasion in endometrial cancer: systematic review and meta-analysis // Gynecol Oncol. – 2018. – Vol. 151(3). – P. 545–553.

17. Efthimiou, O., Seo M., Chalkou K., Debray T., Egger M., Salanti G. Developing clinical prediction models: a step-by-step guide // BMJ. – 2024. – № 3. – Р. e078276. PMID: 39227063.

18. Vickers, A. J., Woo S. Decision curve analysis in the evaluation of radiology research // Eur Radiol. – 2022. – № 32(9). – Р. 5787–5789. Epub 2022 Mar 29. PMID: 35348862.

19. Mijderwijk, H. J., Nieboer D. Is My Clinical Prediction Model Clinically Useful A Primer on Decision Curve Analysis // Acta Neurochir Suppl. – 2022. – Vol. 134. – P. 115–118. PMID: 34862535.

20. Chen, Y., Zhang X., Li J. Development and validation of a clinical prediction model for myometrial invasion in young women with suspected endometrial cancer // J. Clin. Oncol. – 2024. – Vol. 42, № 3. – P. 215–223.

21. Liu, T., Zhao P., Qian W. Clinical-ultrasound combined model for myometrial invasion detection in infertile women with suspected endometrial cancer // Fertil. Steril. – 2024. – Vol. 121, № 3. – P. 456–464.

22. Concin, N. et al. ESMO-ESGO-ESTRO consensus conference on endometrial cancer: diagnosis, treatment and follow-up // Ann Oncol. – 2021. – № 32(4). – P. 450–477.