Vaginal swab test for endometrial cancer enters 3,000-woman US study

A swab test developed by the California-based company PinkDx is being evaluated as a first-line check for endometrial cancer in women with symptoms such as bleeding after menopause. If it performs as intended, many women could avoid an endometrial biopsy. The evidence so far is limited to a very small early study, and the larger trial has not yet reported.

The problem with current work-up

Endometrial cancer begins in the lining of the uterus. Women with abnormal bleeding are usually assessed with transvaginal ultrasound, which measures the thickness of the lining, and often with an endometrial biopsy, in which a thin tube is passed into the uterus to collect a tissue sample. Both procedures can be painful.

Biopsies also fail technically with some regularity. According to figures cited in The Washington Post, about 30% of biopsies in postmenopausal women do not yield enough tissue, because the lining is very thin or the cervical opening is too narrow for the instrument. The need for better options is sharpened by trends in the disease: case numbers are climbing, and death rates are rising too, partly because aggressive subtypes are becoming more common.

How the swab works

The approach relies on the fact that cancer cells in the uterus die and release fragments of genetic material that carry features specific to the tumour. Some of these fragments travel down into the vagina, where a clinician can collect them with a swab and send them for laboratory analysis. In an initial test of 27 women who were undergoing hysterectomy, the company reported that the tumour signal could be detected even in swabs taken from the vaginal opening, the least invasive sampling site.

The ongoing study and its targets

The current study is running at 16 sites in the United States and plans to enrol about 3,000 women with symptoms. Dr June Hou, a gynaecologic oncologist at Columbia University Irving Medical Center, is leading the study at her institution. The trial is expected to finish this year, and company officials have said early results are on track.

The performance goals are specific:

• The swab should detect at least 90% of cancers.
• It should correctly exclude cancer in at least half of women who do not have it, which keeps false alarms in check.

Dr Nicolas Wentzensen, deputy director of the Clinical Genetics Branch at the US National Cancer Institute, noted that if these thresholds are met, the swab could serve as a triage step that removes the need for biopsy in roughly half of women assessed.

Caveats and timeline

Wentzensen also cautioned that the 27-woman study was very small and that its findings must be confirmed in a larger, independent group. Neither the early nor the ongoing results have been described as peer reviewed in the available reports, so the accuracy figures remain targets rather than demonstrated performance.

The swab is not intended to replace follow-up entirely. Women with a positive result would probably still need a biopsy to confirm the diagnosis, while those with a negative result should still see a doctor to investigate other causes of their symptoms.

On regulation, PinkDx plans to run the test only in its own laboratory, which means it would not require approval from the US Food and Drug Administration. The company expects to complete certification with the Centers for Medicare & Medicaid Services by early 2027, which would allow the test to reach patients by mid-2027. Researchers will be watching for published data that show how sensitivity and specificity hold up across ages, tumour subtypes and clinical settings, and whether a negative swab is reliable enough to guide decisions in practice.

Source: New swab test could spare some women a painful biopsy for endometrial cancer (Medical Xpress, 31 October 2026).

Image: AI-generated illustration.