Investigating age and ethnicity as novel high-risk phenotypes in mucinous ovarian cancer: retrospective study in a multi-ethnic population

Abstract

Objectives: Primary mucinous ovarian carcinoma represents 3% of ovarian cancers and is typically diagnosed early, yielding favorable outcomes. This study aims to identify risk factors, focussing on the impact of age and ethnicity on survival from primary mucinous ovarian cancer.

Methods: A retrospective observational study of patients treated at Sandwell and West Birmingham Hospitals NHS Trust and University Hospital Coventry and Warwickshire. Patients included were women aged ≥16 years, with primary mucinous ovarian cancer confirmed by specialist gynecological histopathologist and tumor immunohistochemistry, including cytokeratin-7, cytokeratin-20, and CDX2. Statistical analyses were performed using R integrated development environment, with survival assessed by Cox proportional hazards models and Kaplan-Meier plots.

Results: A total of 163 patients were analyzed; median age at diagnosis was 58 years (range 16-92), 145 (89%) were International Federation of Gynecology and Obstetrics stage I and 43 (26%) patients had infiltrative invasion. Women aged ≤45 years were more likely to have infiltrative invasion (RR=1.38, 95% CI 0.78 to 2.46), with increased risk of death associated with infiltrative invasion (HR=2.29, 95% CI 1.37 to 5.83). Compared with White counterparts, South Asian women were more likely to undergo fertility-sparing surgery (RR=3.52, 95% CI 1.48 to 8.32), and have infiltrative invasion (RR=1.25, 95% CI 0.60 to 2.58). South Asian women undergoing fertility-sparing surgery had worse prognosis than those undergoing traditional staging surgery (HR=2.20, 95% CI 0.39 to 13.14). In FIGO stage I disease, 59% South Asian and 37% White women received adjuvant chemotherapy (p=0.06). South Asian women exhibited a worse overall prognosis than White women (HR=2.07, 95% CI 0.86 to 4.36), particularly pronounced in those aged ≤45 years (HR=8.75, 95% CI 1.22 to 76.38).

Conclusion: This study identified young age as a risk factor for diagnosis of infiltrative invasion. Fertility-sparing surgery in South Asian women is a risk factor for poorer prognosis. South Asian women exhibit poorer overall survival than their White counterparts.

Keywords: Cystadenocarcinoma, Mucinous; Ovarian Cancer; Pathology; Surgery.

Figure 1

Population and patient selection methods. (A) Description of population served by cancer centers involved in this study including population size and ethnic composition. (B) Study inclusion criteria ensuring the selection of eligible participants. *IMD Rank, index of multiple deprivation rank of all 317 local authority councils in England: rank 1=most deprived, rank 317=least deprived. PMOC, primary mucinous ovarian cancer.

Figure 2

Consort diagram illustrating the process of case selection for study inclusion and ethnicity and groupings within age categories. IHC, immunohistochemistry; SWBH, Sandwell and West Birmingham Hospitals; UHCW, University Hospital Coventry and Warwickshire.

Figure 3

Kaplan-Meier survival analysis plots of overall survival in primary mucinous ovarian cancer comparing South Asian and White ethnicity women. (A) Kaplan-Meier plot depicting 5-year overall survival in women diagnosed with primary mucinous ovarian cancer at age ≤45 years stratified by ethnicity; South Asian vs White ethnicity. (B) Kaplan-Meier plot depicting the overall survival in White ethnicity women diagnosed with primary mucinous ovarian cancer stratified by age at diagnosis: ≤45 years vs >45 years. (C) Kaplan-Meier plot depicting overall survival in women diagnosed with primary mucinous ovarian cancer stratified by invasion type: expansile vs infiltrative invasion. (D) Kaplan-Meier plot depicting 5-year overall survival in South Asian women diagnosed with primary mucinous ovarian cancer stratified by surgery type at diagnosis: fertility sparing vs traditional staging surgery (FSS vs TSS).

Figure 4

Risk analysis comparing outcomes based on age and ethnicity. (A) Relative risk (RR) forest plot comparing key prognostic risk factors in primary mucinous ovarian cancer between women aged ≤45 and women >45 years. The forest plot illustrates the relative risk in the two age groups; the risk of death, diagnosis if South Asian, diagnosis with FIGO stage 1C disease, diagnosis with FIGO stage 3/4 disease, infiltrative invasion, and fertility-sparing surgery. Each square represents the point estimate of relative risk with the horizontal line indicating the 95% CI. (B) Relative risk (RR) forest plot comparing key prognostic risk factors in primary mucinous ovarian cancer between South Asian and White ethnicity women. The forest plot illustrates the relative risk in the two ethnic groups; the risk of death, diagnosis at age ≤45 years, diagnosis with FIGO stage 1C disease, diagnosis with FIGO stage 3/4 disease, infiltrative invasion, and fertility-sparing surgery. Each square represents the point estimate of relative risk with the horizontal line indicating the 95% CI. (C) Table describing median survival, univariate and multivariable analyses of hazard ratios (HRs) with 95% confidence intervals in primary mucinous ovarian cancer. Exposures included in multivariable analyses identifiers: age, ethnicity, stage, invasion type, and surgery type. *Age assessed as a continuous variable with hazard reported for each additional year at age of diagnosis beginning at age 16 years. FIGO, International Federation of Gynecology and Obstetrics.