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PET/CT in breast and gynaecological cancers
In early breast cancer PET/CT is not needed; it enters when disease is locally advanced (stage III), inflammatory or suspected of recurrence; in locally advanced cervical cancer PET/CT is the preferred staging study for pelvic and para-aortic nodes.
Why it matters in the exam
The exam asks whether PET has a role in a woman with a small breast tumour — the answer: no, in stage I–II without symptoms, because the rate of occult metastases is low and false positives are many. PET is recommended in stage III, in inflammatory cancer, and is considered in aggressive tumours (triple negative, HER2-positive) in young women with extensive local disease. It does not replace sentinel node biopsy for the axilla, because it cannot detect micrometastases. Lobular and low-grade carcinomas take up FDG weakly, and lobular bone metastases may be sclerotic and negative.
In suspected recurrence — back pain, rising markers or an unclear CT finding — PET/CT is more sensitive than CT and bone scintigraphy separately. F-18 fluoroestradiol (FES) PET shows oestrogen receptor expression in all lesions and helps when biopsy is difficult. Genomic tests and receptors (ER, PR, HER2) determine treatment; PET does not replace them.
In cervical cancer PET/CT is recommended from stage IB3 upwards (large or locally advanced tumour) to detect para-aortic nodes and define the radiation field; in very early disease (IA) it is not needed. Causes of false positives in the pelvis: bowel uptake, urine in the ureters, and ovaries or endometrium in women of reproductive age depending on the menstrual phase. Causes of false negatives: small nodes. In ovarian cancer PET is used mainly in suspected recurrence with a rising CA-125, and in endometrial cancer to assess metastases in high-risk disease.
Key points
- Early breast cancer — no routine PET.
- Stage III, inflammatory or recurrence — PET/CT.
- PET does not replace the sentinel node.
- Cervix IB3 and above — PET/CT for nodes.
- Ovaries and endometrium take up physiologically according to the cycle.
Summary table
| Situation | PET/CT | Note |
|---|---|---|
| Breast cancer stage I–II | Not routine | Axilla — sentinel node |
| Breast cancer stage III or inflammatory | Recommended | Replaces CT and bone scintigraphy |
| Breast cancer — suspected recurrence | Sensitive | Lobular may be negative |
| Cervix IB3 and above | Recommended | Para-aortic nodes and radiation field |
| Ovary — rising CA-125 | Consider | Small peritoneal recurrence may be negative |
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Sources
- NCCN Guidelines: Breast Cancer, 2025 — Systemic staging and FDG PET-CT
- NCCN Guidelines: Cervical Cancer, 2025 — Imaging for staging and surveillance
- ESGO/ESTRO/ESP Guidelines for the Management of Patients with Cervical Cancer, 2023 — Pretreatment imaging
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.