A Story That Happens More Often Than You Think
"Doctor, I really don't understand. I get a TCT test every year during my physical exam, and the reports always say 'no intraepithelial lesion or malignancy.' But last week I was diagnosed with cervical adenocarcinoma. How is this possible?"
In my clinic, Ms. Wang (pseudonym) held a stack of "all normal" TCT reports, her voice trembling.
TCT (Liquid-Based Thin-Layer Cytology) is one of the most commonly used cervical cancer screening methods, designed to detect abnormal cervical cells early. During the test, a doctor uses a small brush to collect exfoliated cells from the cervical surface. If cell morphology appears normal, the report reads "no intraepithelial lesion or malignancy" — what we commonly call a "normal TCT."
Ms. Wang's experience is a tragedy no gynecologist wants to see, and it exposes a blind spot that many people — even some non-specialist doctors — don't know about:
A normal TCT does NOT mean your cervix is absolutely safe.
Why Can You Still Get Cervical Cancer with Normal TCT Results?
This comes down to HPV virus types and where they attack.
TCT produces "false negatives" (disease present but undetected) largely because not all HPV-infected areas are within reach of the TCT brush.
Ms. Wang's pathology report showed infection with HPV type 45.
Type 45 is a particularly special HPV strain. A 2024 Lancet analysis of over 110,000 cervical cancer cases globally found HPV 45 accounts for only 4.8% — far less than types 16 and 18, which can make people lower their guard.
However, when we divide cervical cancer into its two major categories — Squamous Cell Carcinoma (SCC) and Adenocarcinoma (ADC) — the viral distribution tells a different story:
| Cancer Type | HPV 16 | HPV 18 | HPV 45 | Combined 18+45 |
|---|---|---|---|---|
| Squamous Cell Carcinoma | Dominant | Lower | Low | — |
| Adenocarcinoma | ~50% | 31.6% | 11.6% | 43% of cases |
HPV types 45 and 18 preferentially attack glandular epithelial cells deep within the cervical canal. Because the lesions are located deep, the standard TCT brush has difficulty reaching these abnormal cells, creating false-negative results.
The Hidden Risk: Non-HPV-Related Cervical Cancer
Beyond missed diagnoses due to deep lesion location, the medical community has recently confirmed a paradigm-shifting phenomenon: not all cervical cancers are caused by HPV.
According to the Chinese Expert Consensus on Pathological Diagnosis of Non-HPV-Related Cervical Cancer (2026 Edition), approximately 5%–12% of cervical squamous cell carcinomas and 15%–38% of cervical adenocarcinomas are "non-HPV-related cervical cancers."
These patients may test HPV-negative year after year, yet tumors can still grow silently.
Characteristics of Non-HPV Cervical Cancer (e.g., Gastric-Type Adenocarcinoma)
| Feature | Description |
|---|---|
| Extremely hidden | Often grows deep in the cervical canal; TCT brush can't reach it; cells closely resemble normal cells |
| Masters of disguise | Early-stage cervix may only appear "enlarged" with no obvious mass; the only symptom may be watery vaginal discharge |
| Highly aggressive | Often diagnosed at advanced stages; prone to distant metastasis (ovaries, lungs); less sensitive to chemo/radiation |
Important: Even if you've never been infected with HPV, even if both HPV and TCT tests are negative every year — if you experience abnormal vaginal discharge, watery secretions, or irregular bleeding after menopause, you must seek medical attention immediately.
How to Optimize Your Screening Strategy
Recommended Screening Schedule
We recommend beginning screening at age 25–30 and continuing until age 65. Those with high-risk factors should start earlier.
| Age Group | Recommended Approach | Frequency |
|---|---|---|
| 25–29 | HPV test alone OR HPV + TCT co-testing | Every 3 years (HPV alone) or every 3 years (co-testing) |
| 30–65 | HPV + TCT co-testing (preferred) | Every 3–5 years |
| 65+ | May stop if adequate prior screening was negative | Discuss with doctor |
What to Do Based on HPV Results
HPV types 16 or 18 detected: These carry the highest cancer risk. Even with normal TCT, colposcopy is recommended immediately. Early detection prevents disease progression.
HPV type 45 detected: Closely linked to adenocarcinoma and often hidden. Even with normal TCT, discuss further evaluation with your doctor.
Other high-risk types (31, 33, 52, 58, etc.): If TCT is normal, this is usually a transient infection. Allow 1–2 years for your immune system to clear the virus. Recheck HPV + TCT in 12 months.
Note: HPV-positive results don't warrant panic. Most HPV infections are transient and cleared by the immune system. Currently, no oral or topical medication has proven effective at eradicating HPV.
I've Been Vaccinated — Do I Still Need Screening?
This is one of the most common questions. HPV vaccines do prevent most cervical cancers, especially the 9-valent vaccine covering seven high-risk types:
| Coverage | Protection Rate |
|---|---|
| Global average | ~90% of invasive cervical cancers |
| China (higher prevalence of types 52, 58) | ~95.4% |
However, 5%–10% of cervical cancers are caused by high-risk HPV types not covered by any vaccine (types 35, 39, 51, 56, 59, 68, etc.).
Additionally, if you were already infected with a particular HPV type before vaccination, the vaccine cannot clear that existing infection.
Clinical consensus: Vaccination is "primary prevention." Regular screening is "secondary prevention." Both are essential and complementary — neither alone is sufficient.
Lifestyle Measures to Reduce Your Risk
Beyond HPV vaccination and regular HPV + TCT co-testing:
Safe Sexual Practices
Consistent condom use significantly reduces HPV transmission between partners (female HPV infection rates reduced by ~70%, male penile HPV infection rates by ~50%). Avoiding early sexual debut and limiting number of partners also reduces high-risk HPV exposure.
Quit Smoking
Smoking is a recognized independent risk factor for cervical cancer. Tobacco chemicals weaken local cervical immunity, prolong HPV infection duration, and accelerate cellular DNA damage — promoting progression from infection to precancer to cancer.
Maintain a Healthy Lifestyle
HPV clearance primarily depends on your immune system. Regular sleep schedules, moderate exercise, and a balanced diet rich in antioxidants (fresh fruits and vegetables) help maintain strong immunity and improve your body's ability to clear HPV naturally.
Key Takeaways
| Topic | Key Point |
|---|---|
| TCT limitations | Normal TCT ≠ cancer-free; deep lesions and adenocarcinomas can be missed |
| HPV 45 & 18 | Attack deep glandular cells; standard brush can't reach them |
| Non-HPV cancers | 5–38% of cervical cancers are HPV-independent |
| Optimal screening | HPV + TCT co-testing every 3–5 years from age 25–30 |
| Vaccination + screening | Both essential; vaccine alone doesn't eliminate need for screening |
| Warning signs | Watery discharge, irregular bleeding → seek immediate evaluation |
FAQ
Q: If my TCT is normal every year, am I safe from cervical cancer? A: Not necessarily. TCT has blind spots — it may miss adenocarcinomas deep in the cervical canal and non-HPV-related cancers. Combining HPV testing with TCT significantly reduces false-negative risk.
Q: Which HPV types are most dangerous? A: HPV 16 is the most carcinogenic overall. For adenocarcinoma specifically, HPV 18 and 45 are particularly dangerous because they attack deep glandular cells that standard screening may miss.
Q: Can cervical cancer develop without any HPV infection? A: Yes. Approximately 5–12% of squamous cell carcinomas and 15–38% of adenocarcinomas are non-HPV-related. These are often more aggressive and harder to detect early.
Q: How often should I get screened if I've been vaccinated? A: Follow the same screening schedule as unvaccinated women. The vaccine doesn't cover all cancer-causing HPV types, and it cannot clear pre-existing infections. Screening remains essential.
References
- Wei F, Georges D, Man I, et al. Causal attribution of human papillomavirus genotypes to invasive cervical cancer worldwide: a systematic analysis of the global literature. The Lancet. 2024;404(10451):435-444.
- Bosch FX, de Sanjose S. HPV types 16, 18, 45 and 31: the most important human papillomavirus types in the aetiology of cervical cancer. International Journal of Infectious Diseases. 2008;12:e3-e4.
- Chinese Anti-Cancer Association Cervical Cancer Committee. Chinese Expert Consensus on Pathological Diagnosis of Non-HPV-Related Cervical Cancer (2026 Edition). Chinese Journal of Practical Gynecology and Obstetrics. 2026;42(2):171-181.
- Pirog EC, Lloveras B, Molijn A, et al. HPV prevalence and genotypes in different histological subtypes of cervical adenocarcinoma, a worldwide analysis of 760 cases. Modern Pathology. 2014;27(12):1559-1567.
- Schiffman M, Mirabello L, Egemen D, et al. The combined finding of HPV 16, 18, or 45 and cytologic Atypical Glandular Cells indicates a greatly elevated risk of in situ and invasive cervical adenocarcinoma. Gynecologic Oncology. 2023;174:253-261.
