Cervical cancer — staging

ESGO/ESTRO/ESP cervical cancer imaging guidance (2023)

The decision imaging supports is surgery versus chemoradiotherapy, and it turns on parametrial invasion — an interruption of the low-signal cervical stromal ring. That ring is only visible on thin, small-field-of-view T2 acquired in planes referenced to the cervical canal, not to the patient.

Histologically confirmed cervical carcinoma requiring assessment of tumour size, parametrial and vaginal extension, nodal disease and hydronephrosis before treatment.

Referenced decision support — confirm against your local protocol.

Decision support, not a directive. Protocols and timings shown are typical published ones — your local protocol takes precedence, and the vetting radiologist decides.

The request in front of you

Everything is optional. Leave a field alone and the answer assumes nothing — the verdict updates as you go.

Study requested

What the referrer actually asked for. It is evidence of intent, not a constraint on the right answer.

Contrast as written

What the request form says, not what it should say.

Age

Pick a band, or type an exact age if it matters.

years

Pregnancy status

Renal risk factors

The question a vetter can actually answer from the request. An explicit “none known” is a real answer, and it removes checks rather than deferring them.

Previous contrast reaction

The pathway — tap anything already done

Marking a study complete moves the answer on. A patient arrives partway through a pathway far more often than at the start of one.

Accept as requested

MRI Pelvis — cervical cancer staging

MRI Pelvis (Gynaecological)

What we'd amend, and why

Parametrial invasion is defined by loss of the low-signal fibrous stromal ring that surrounds the cervical canal, and that ring is a millimetre-scale structure. Resolving it needs a small field of view, thin slices, and oblique planes referenced to the canal itself — oblique-axial perpendicular to it for parametrial assessment and oblique-coronal parallel to it for the fornices and vagina. Planes referenced to the patient rather than the canal are the standard cause of parametrial overcall, and an overcall moves a woman from surgery to chemoradiotherapy. A separate large field-of-view acquisition handles nodes and the upper abdomen.

Nothing needs resolving before this goes ahead. Routine checks below are owned downstream.

How was this decided?

pathwaystandard — Adults — local and nodal staging
rulerule-mr-device-screening — MR safety screening for implants and foreign bodies; checked by Radiographer at the scanner
rulerule-contrast-reaction-premed — Prior contrast reaction and elective premedication; checked by Nurse before the scan
rulerule-gadolinium-renal — Kidney function and gadolinium-based contrast; checked by Radiographer at the scanner
rulerule-pregnancy-gadolinium — Gadolinium in known or possible pregnancy; checked by Radiographer at the scanner
rulerule-iv-access — Intravenous access adequate for the planned injection; checked by Radiographer at the scanner

Decision support only. Local protocol takes precedence.

Handled at the scanner(2)nothing for you to do

Settled and owned downstream. Each returns to a radiologist only on the stated trigger.

MR safety screening for implants and foreign bodies
Complete the MR safety questionnaire, verify implant labelling and its stated conditions of use against this scanner and this protocol, and ensure no ferromagnetic object enters Zone IV.
Radiographer at the scannerBefore the scan
Flags back if: An implant or retained foreign body that is MR Unsafe, unlabelled, or cannot be identified; or an MR Conditional device whose stated conditions this scanner or the requested protocol cannot satisfy; or a credible unexcluded intraocular metallic foreign body history.
Intravenous access adequate for the planned injection
Site and test a cannula that supports the protocol flow rate, preferring an antecubital or large forearm vein, and observe the injection for extravasation. A 20-gauge or larger cannula is preferred for flow rates of 3 mL/s or more.
Radiographer at the scannerAt the scanner
Flags back if: No cannula can be sited that supports the protocol flow rate — for example only a 22-gauge hand or foot cannula for a CT angiogram needing 4–5 mL/s; or the only available access is a central line or port that is not labelled power-injectable; or an extravasation occurs.

Pathways

Big forks are separate pathways; the first whose conditions match is the one used.

Adults — local and nodal staging

Matches your inputsDefault

Role	Study & protocol	Why this answers the question
First line	MRI Pelvis (Gynaecological) MRI Pelvis — cervical cancer staging usually appropriate	Parametrial invasion is defined by loss of the low-signal fibrous stromal ring that surrounds the cervical canal, and that ring is a millimetre-scale structure. Resolving it needs a small field of view, thin slices, and oblique planes referenced to the canal itself — oblique-axial perpendicular to it for parametrial assessment and oblique-coronal parallel to it for the fornices and vagina. Planes referenced to the patient rather than the canal are the standard cause of parametrial overcall, and an overcall moves a woman from surgery to chemoradiotherapy. A separate large field-of-view acquisition handles nodes and the upper abdomen.
Second line	FDG PET-CT FDG PET-CT — skull base to mid-thigh	The nodal and distant staging tool in locally advanced disease. Para-aortic nodal involvement extends the radiotherapy field, and detecting it before planning rather than after is the whole reason the study is done up front.
Second line	CT Abdomen and Pelvis CT Abdomen and Pelvis — Portal Venous Phase	Where PET-CT is unavailable, contrast-enhanced CT provides nodal and visceral staging and identifies hydronephrosis, though it cannot assess parametrial invasion and should never be substituted for the pelvic MRI.

Pitfalls

Imaging in straight anatomical planes rather than planes referenced to the cervical canal, which is the classic cause of parametrial overcall.
A field of view too large to resolve the low-signal stromal ring, so its integrity cannot be judged at all.
Superior coverage stopping at the pelvic brim, missing para-aortic nodes and hydronephrosis.
Scanning shortly after cone biopsy, when oedema is indistinguishable from residual disease.
Substituting CT for MRI in local staging. It cannot see the structure the decision depends on.

Priors — what to pull first

Record the date of any cone biopsy or large loop excision. Post-procedural oedema mimics residual tumour and imaging too soon after it overstages.
For response assessment after chemoradiotherapy, the pre-treatment study planned in the same oblique geometry is the only useful comparator.

What makes a good request

Current European guidance places MRI as the standard for local staging and pelvic nodal assessment, with PET-CT adding para-aortic nodal and distant assessment in locally advanced disease.
Coverage must extend superiorly to the renal hila. Hydronephrosis alters stage in its own right, and the para-aortic nodal station changes the radiotherapy field.
For fertility-sparing trachelectomy the decisive measurement is the distance from the upper tumour margin to the internal os, and it requires a sagittal acquisition planned along the canal.
Contrast is not universally required — high-resolution T2 with diffusion answers most local staging questions — and is added mainly for suspected bladder or rectal invasion, fistula, small-volume disease and post-treatment assessment. Practice differs on whether it is routine.

How these studies are acquired

Contrast, phases and timing for every study on the pathways above.

MRI Pelvis — cervical cancer staging FDG PET-CT — skull base to mid-thigh CT Abdomen and Pelvis — Portal Venous Phase

Confirm locally

MRI Pelvis — cervical cancer staging: timings are typical — confirm against local protocol.
Timings, contrast volumes and rates above are typical published values. Your department's protocol, scanner and patient population decide the actual numbers.
Safety thresholds and premedication policy follow local policy where it differs from the cited guidance.

References

Implemented from the cited published sources. Educational and workflow support only; confirm against current guidelines and local policy before clinical use.