Distribution of endometriosis phenotypes according to patients' age in adult women with surgical evaluation.

Abstract

Study question: What is the distribution of endometriosis phenotypes according to age in adult women undergoing surgery?

Summary answer: The phenotype of endometriosis did not significantly vary after 24 years old.

What is known already: The phenotypic evolution of endometriosis over time remains unclear. While adolescents can exhibit any type of endometriosis lesions, ovarian endometriosis (OMA) and/or deep-infiltrating endometriosis (DIE) tend to increase with age in young adults. In adulthood, understanding the evolution of lesions is crucial for disease management, but the literature on this subject is limited. This study aims to examine the distribution of endometriosis phenotypes in relation to age among adult patients requiring surgical treatment.

Study design, size, duration: This observational cohort study included patients aged between ≥18 and ≤42 years, who underwent surgery for benign gynecological conditions at our institution between January 2004 and December 2022. A standardized questionnaire was completed for each patient during a face-to-face interview conducted by the surgeon in the month preceding surgery. Women with histologically proven endometriosis were included.

Participants/materials, setting, methods: The distribution of endometriosis phenotypes (isolated superficial (SUP) endometriosis, OMA ± SUP, DIE ± SUP/OMA) was compared between young adults (≤24 years) and adults (>24 years) and among adults (25-28 years, 29-33 years, 34-38 years, 39 to ≤42 years) using univariate and multivariate analysis. The distribution of different subtypes of DIE (uterosacral ligament(s), vagina, bladder, intestine, and ureter), OMA size, and intensity of pain symptoms were also examined.

Main results and the role of chance: A total of 1311 adult women with histologically proven endometriosis were included. In women aged 24 years or younger (n = 116), the distribution of endometriosis phenotypes differed significantly from women older than 24 years (n = 1195): The frequency of the DIE ± SUP/OMA phenotype was lower (41.4% versus 56.1%, respectively), while the rate of isolated superficial lesions was higher (from 32.0% versus 25.9%) (P = 0.001). In the group of women aged >24 years, a significantly higher proportion of vaginal DIE lesions (P = 0.012) and a lower proportion of uterosacral ligament DIE lesions (P = 0.004) were found compared to women aged ≤24 years. No significant differences were observed in terms of endometrioma size. Between the ages of 25 and 42 years, there were no significant changes in the distribution of endometriosis phenotypes after univariate and multivariate analysis. The distribution of subtype of DIE lesions did not significantly change with age between 25 and 42 years. Concerning pain symptom scores, there was a significant decrease with age for dysmenorrhea and dyspareunia.

Limitations, reasons for caution: Inclusion of only surgical patients may have introduced a selection bias. Women referred to our center may have suffered from particularly severe clinical forms of endometriosis.

Wider implications of the findings: This study highlights that endometriosis presentation did not change with age in adult women. Further research on endometriosis phenotype evolution is necessary to assist practitioners in clinical decisions and treatment strategies.

Study funding/competing interests: None declared.

Trial registration number: N/A.