#1493 What defines infiltrative invasion as a poor prognostic factor in primary mucinous ovarian cancer? – A multicentre retrospective cohort

Tejumola Olaoye; Ayushi; Marc D. Algera; William Boyle; Richard Edmondson; Satyam Kumar; Alicia Leon Del Castillo; Fabienne C. Lof; Alexandros Laios; Gemma Owens; Saurabh Phadnis; Hooman Soleymani Majd; Anthony Williams; Christianne A.R. Lok; Sudha Sundar

doi:10.1016/j.ijgc.2025.102910

Abstract

Introduction/Background Two invasion subtypes of Mucinous ovarian cancer (MOC) exist: infiltrative (poorer prognosis) and expansile (better prognosis). The histopathological criteria defining infiltrative invasion vary across studies, with the WHO requiring ≥5mm linear extension of an invasive component but alternative definitions have been described particularly when the two invasive components coexist. We investigated if any extent of destructive stromal invasion has prognostic significance.

Methodology International retrospective cohort study from UK and Dutch registries of MOC diagnosed January 2005-December 2023. Cases were reviewed at diagnosis by specialist gynae-pathologists and subsequently re-reviewed by three expert gynae-pathologists. Three groups were compared, expansile, infiltrative or tumours with destructive stromal invasion not meeting the threshold for infiltrative invasion (mixed). Survival was assessed using Cox proportional hazards models and Kaplan-Meier analysis.

Results Of 724 patients, expansile invasion was identified in 439 (61%), infiltrative in 135 (19%), and mixed in 102 (14%) of the patients (Figure 1B). The 5-year overall survival was 90% for expansile, 68% for infiltrative, and 79% for mixed invasion (Figure 1C), Compared to expansile the hazard ratio (HR) for death in infiltrative group was 3.18 (95% CI 2.12 – 4.76); and 2.04 (95% CI 1.24 -3.36) in mixed group. In 627 patients with stage I MOC, expansile invasion had a 5-year survival of 93% compared to 84% for patients with infiltrative invasion and 84% with mixed invasion (Figure 1D). In stage I disease, when compared to expansile, the HR for death was 2.02 (95% CI 1.14-3.58) in infiltrative and 1.99 (95% CI 1.10-3.61) in mixed invasion.

Conclusion In the largest cohort assessing invasion in MOC to date, any destructive stromal invasion, even in stage I disease, is associated with poorer prognosis. Tumours showing any component of destructive stromal invasion should be managed as infiltrative invasion.

Acknowledgement We would like to acknowledge all additional members who participated in the UK data collection as part of the MUCOVA collaboration.

Original language	English
Article number	102910
Pages (from-to)	5-6
Number of pages	2
Journal	International Journal of Gynecological Cancer
Volume	36
Issue number	2, Supplement 1
DOIs	https://doi.org/10.1016/j.ijgc.2025.102910
Publication status	Published - 17 Feb 2026
Event	ESGO's 27th European Gynaecological Oncology Congress: The Wind of Innovation in Women's Cancer - Bella Center Copenhagen, Copenhagen, Denmark Duration: 26 Feb 2026 → 28 Feb 2026 Conference number: 27 https://www.esgo.org/esgo-2026-congress/

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SDG 3 Good Health and Well-being

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Olaoye, T., Ayushi, Algera, M. D., Boyle, W., Edmondson, R., Kumar, S., Del Castillo, A. L., Lof, F. C., Laios, A., Owens, G., Phadnis, S., Majd, H. S., Williams, A., Lok, C. A. R., & Sundar, S. (2026). #1493 What defines infiltrative invasion as a poor prognostic factor in primary mucinous ovarian cancer? – A multicentre retrospective cohort. International Journal of Gynecological Cancer, 36(2, Supplement 1), 5-6. Article 102910. https://doi.org/10.1016/j.ijgc.2025.102910

@article{eff41625b16a40c0b640e02b08cd8753,

title = "\#1493 What defines infiltrative invasion as a poor prognostic factor in primary mucinous ovarian cancer? – A multicentre retrospective cohort",

abstract = "Introduction/Background Two invasion subtypes of Mucinous ovarian cancer (MOC) exist: infiltrative (poorer prognosis) and expansile (better prognosis). The histopathological criteria defining infiltrative invasion vary across studies, with the WHO requiring ≥5mm linear extension of an invasive component but alternative definitions have been described particularly when the two invasive components coexist. We investigated if any extent of destructive stromal invasion has prognostic significance. Methodology International retrospective cohort study from UK and Dutch registries of MOC diagnosed January 2005-December 2023. Cases were reviewed at diagnosis by specialist gynae-pathologists and subsequently re-reviewed by three expert gynae-pathologists. Three groups were compared, expansile, infiltrative or tumours with destructive stromal invasion not meeting the threshold for infiltrative invasion (mixed). Survival was assessed using Cox proportional hazards models and Kaplan-Meier analysis. Results Of 724 patients, expansile invasion was identified in 439 (61\%), infiltrative in 135 (19\%), and mixed in 102 (14\%) of the patients (Figure 1B). The 5-year overall survival was 90\% for expansile, 68\% for infiltrative, and 79\% for mixed invasion (Figure 1C), Compared to expansile the hazard ratio (HR) for death in infiltrative group was 3.18 (95\% CI 2.12 – 4.76); and 2.04 (95\% CI 1.24 -3.36) in mixed group. In 627 patients with stage I MOC, expansile invasion had a 5-year survival of 93\% compared to 84\% for patients with infiltrative invasion and 84\% with mixed invasion (Figure 1D). In stage I disease, when compared to expansile, the HR for death was 2.02 (95\% CI 1.14-3.58) in infiltrative and 1.99 (95\% CI 1.10-3.61) in mixed invasion. Conclusion In the largest cohort assessing invasion in MOC to date, any destructive stromal invasion, even in stage I disease, is associated with poorer prognosis. Tumours showing any component of destructive stromal invasion should be managed as infiltrative invasion. Acknowledgement We would like to acknowledge all additional members who participated in the UK data collection as part of the MUCOVA collaboration.",

author = "Tejumola Olaoye and Ayushi and Algera, \{Marc D.\} and William Boyle and Richard Edmondson and Satyam Kumar and \{Del Castillo\}, \{Alicia Leon\} and Lof, \{Fabienne C.\} and Alexandros Laios and Gemma Owens and Saurabh Phadnis and Majd, \{Hooman Soleymani\} and Anthony Williams and Lok, \{Christianne A.R.\} and Sudha Sundar",

year = "2026",

month = feb,

day = "17",

doi = "10.1016/j.ijgc.2025.102910",

language = "English",

volume = "36",

pages = "5--6",

journal = "International Journal of Gynecological Cancer",

issn = "1525-1438",

publisher = "Lippincott Williams and Wilkins",

number = "2, Supplement 1",

note = "ESGO's 27th European Gynaecological Oncology Congress : The Wind of Innovation in Women's Cancer, ESGO 2026 ; Conference date: 26-02-2026 Through 28-02-2026",

url = "https://www.esgo.org/esgo-2026-congress/",

}

Olaoye, T, Ayushi, Algera, MD, Boyle, W, Edmondson, R, Kumar, S, Del Castillo, AL, Lof, FC, Laios, A, Owens, G, Phadnis, S, Majd, HS, Williams, A, Lok, CAR & Sundar, S 2026, '#1493 What defines infiltrative invasion as a poor prognostic factor in primary mucinous ovarian cancer? – A multicentre retrospective cohort', International Journal of Gynecological Cancer, vol. 36, no. 2, Supplement 1, 102910, pp. 5-6. https://doi.org/10.1016/j.ijgc.2025.102910

#1493 What defines infiltrative invasion as a poor prognostic factor in primary mucinous ovarian cancer? – A multicentre retrospective cohort. / Olaoye, Tejumola; Ayushi; Algera, Marc D. et al.
In: International Journal of Gynecological Cancer, Vol. 36, No. 2, Supplement 1, 102910, 17.02.2026, p. 5-6.

Research output: Contribution to journal › Abstract › peer-review

TY - JOUR

T1 - #1493 What defines infiltrative invasion as a poor prognostic factor in primary mucinous ovarian cancer? – A multicentre retrospective cohort

AU - Olaoye, Tejumola

AU - Ayushi, null

AU - Algera, Marc D.

AU - Boyle, William

AU - Edmondson, Richard

AU - Kumar, Satyam

AU - Del Castillo, Alicia Leon

AU - Lof, Fabienne C.

AU - Laios, Alexandros

AU - Owens, Gemma

AU - Phadnis, Saurabh

AU - Majd, Hooman Soleymani

AU - Williams, Anthony

AU - Lok, Christianne A.R.

AU - Sundar, Sudha

N1 - Conference code: 27

PY - 2026/2/17

Y1 - 2026/2/17

N2 - Introduction/Background Two invasion subtypes of Mucinous ovarian cancer (MOC) exist: infiltrative (poorer prognosis) and expansile (better prognosis). The histopathological criteria defining infiltrative invasion vary across studies, with the WHO requiring ≥5mm linear extension of an invasive component but alternative definitions have been described particularly when the two invasive components coexist. We investigated if any extent of destructive stromal invasion has prognostic significance. Methodology International retrospective cohort study from UK and Dutch registries of MOC diagnosed January 2005-December 2023. Cases were reviewed at diagnosis by specialist gynae-pathologists and subsequently re-reviewed by three expert gynae-pathologists. Three groups were compared, expansile, infiltrative or tumours with destructive stromal invasion not meeting the threshold for infiltrative invasion (mixed). Survival was assessed using Cox proportional hazards models and Kaplan-Meier analysis. Results Of 724 patients, expansile invasion was identified in 439 (61%), infiltrative in 135 (19%), and mixed in 102 (14%) of the patients (Figure 1B). The 5-year overall survival was 90% for expansile, 68% for infiltrative, and 79% for mixed invasion (Figure 1C), Compared to expansile the hazard ratio (HR) for death in infiltrative group was 3.18 (95% CI 2.12 – 4.76); and 2.04 (95% CI 1.24 -3.36) in mixed group. In 627 patients with stage I MOC, expansile invasion had a 5-year survival of 93% compared to 84% for patients with infiltrative invasion and 84% with mixed invasion (Figure 1D). In stage I disease, when compared to expansile, the HR for death was 2.02 (95% CI 1.14-3.58) in infiltrative and 1.99 (95% CI 1.10-3.61) in mixed invasion. Conclusion In the largest cohort assessing invasion in MOC to date, any destructive stromal invasion, even in stage I disease, is associated with poorer prognosis. Tumours showing any component of destructive stromal invasion should be managed as infiltrative invasion. Acknowledgement We would like to acknowledge all additional members who participated in the UK data collection as part of the MUCOVA collaboration.

AB - Introduction/Background Two invasion subtypes of Mucinous ovarian cancer (MOC) exist: infiltrative (poorer prognosis) and expansile (better prognosis). The histopathological criteria defining infiltrative invasion vary across studies, with the WHO requiring ≥5mm linear extension of an invasive component but alternative definitions have been described particularly when the two invasive components coexist. We investigated if any extent of destructive stromal invasion has prognostic significance. Methodology International retrospective cohort study from UK and Dutch registries of MOC diagnosed January 2005-December 2023. Cases were reviewed at diagnosis by specialist gynae-pathologists and subsequently re-reviewed by three expert gynae-pathologists. Three groups were compared, expansile, infiltrative or tumours with destructive stromal invasion not meeting the threshold for infiltrative invasion (mixed). Survival was assessed using Cox proportional hazards models and Kaplan-Meier analysis. Results Of 724 patients, expansile invasion was identified in 439 (61%), infiltrative in 135 (19%), and mixed in 102 (14%) of the patients (Figure 1B). The 5-year overall survival was 90% for expansile, 68% for infiltrative, and 79% for mixed invasion (Figure 1C), Compared to expansile the hazard ratio (HR) for death in infiltrative group was 3.18 (95% CI 2.12 – 4.76); and 2.04 (95% CI 1.24 -3.36) in mixed group. In 627 patients with stage I MOC, expansile invasion had a 5-year survival of 93% compared to 84% for patients with infiltrative invasion and 84% with mixed invasion (Figure 1D). In stage I disease, when compared to expansile, the HR for death was 2.02 (95% CI 1.14-3.58) in infiltrative and 1.99 (95% CI 1.10-3.61) in mixed invasion. Conclusion In the largest cohort assessing invasion in MOC to date, any destructive stromal invasion, even in stage I disease, is associated with poorer prognosis. Tumours showing any component of destructive stromal invasion should be managed as infiltrative invasion. Acknowledgement We would like to acknowledge all additional members who participated in the UK data collection as part of the MUCOVA collaboration.

U2 - 10.1016/j.ijgc.2025.102910

DO - 10.1016/j.ijgc.2025.102910

M3 - Abstract

SN - 1525-1438

VL - 36

SP - 5

EP - 6

JO - International Journal of Gynecological Cancer

JF - International Journal of Gynecological Cancer

IS - 2, Supplement 1

M1 - 102910

T2 - ESGO's 27th European Gynaecological Oncology Congress

Y2 - 26 February 2026 through 28 February 2026

ER -

#1493 What defines infiltrative invasion as a poor prognostic factor in primary mucinous ovarian cancer? – A multicentre retrospective cohort

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