Cervical Cancer
Cervical cancer arises from the cervix, the lower part of the uterus opening into the vagina. It is unusual among cancers in being almost entirely attributable to a single cause—persistent infection with high-risk types of human papillomavirus—and therefore almost entirely preventable. Two interventions have transformed it: screening, which detects precancerous changes years before cancer develops and allows them to be treated, and HPV vaccination, which prevents the infection in the first place. Where both are well established, incidence has fallen dramatically, and the World Health Organization has set out a global strategy to eliminate cervical cancer as a public health problem. Where access is limited, it remains a leading cause of cancer death in women.
What is it?
The cervix is the lower, narrow portion of the uterus, projecting into the top of the vagina, with a small central canal connecting the two. Its outer surface is covered by flat squamous cells like those lining the vagina, while the canal is lined by column-shaped glandular cells. The boundary between these two cell types is called the transformation zone, and it is where almost all cervical cancers arise—because cells actively changing from one type to another are more vulnerable to the genetic disruption that HPV causes.
Human papillomavirus is a very common virus transmitted through skin-to-skin genital contact. Most sexually active people are infected at some point, and in the great majority the immune system clears it within one to two years without any consequence. It is persistent infection—the virus remaining active for years—that causes problems.
There are many HPV types, and they differ considerably. Low-risk types cause genital warts but not cancer. High-risk types, principally types 16 and 18, which together account for roughly 70% of cervical cancers, produce proteins that interfere with the cell’s normal controls on growth and DNA repair. Over years, this leads to progressive abnormality of the cervical cells.
That progression is the reason cervical cancer is preventable in a way few cancers are. Persistent infection leads to precancerous change, known as cervical intraepithelial neoplasia and graded from CIN 1 through CIN 3, or in the newer terminology as low-grade and high-grade squamous intraepithelial lesions. These changes are confined to the surface layer and are not cancer. They typically take a decade or more to progress to invasive disease, and many regress spontaneously—particularly the lower grades and particularly in younger women. This long window, and the accessibility of the cervix to examination and sampling, is exactly what makes screening effective.
Cervical cancer itself has two main types. Squamous cell carcinoma accounts for the majority and arises from the surface cells. Adenocarcinoma arises from the glandular cells within the canal, is less common but has become proportionally more frequent, and is harder to detect on cytology-based screening because it develops higher in the canal—one of the reasons HPV-based screening, which does not depend on sampling abnormal cells directly, represents an improvement. Rarer types include adenosquamous carcinoma, small cell neuroendocrine carcinoma, which behaves aggressively, and clear cell carcinoma.
The risk factors beyond HPV largely reflect either increased likelihood of persistent infection or reduced ability to clear it.
Smoking roughly doubles risk and impairs local immune clearance of the virus.
Immunosuppression is significant. Women with HIV have substantially elevated risk and are advised to screen more frequently, and cervical cancer is an AIDS-defining illness. Transplant recipients and others on long-term immunosuppression carry similar considerations.
Long-term use of combined oral contraception is associated with a modest increase in risk that declines after stopping, and this must be weighed against its substantial protective effect against endometrial and ovarian cancer—on balance, the overall cancer effect of the combined pill is favourable.
Higher numbers of full-term pregnancies, earlier age at first pregnancy, and other sexually transmitted infections are associated. Exposure in utero to diethylstilbestrol, a medication given until the early 1970s, is associated with clear cell adenocarcinoma of the cervix and vagina in daughters.
The most important risk factor in practice, however, is never having been screened or having been screened irregularly. In countries with organised programmes, the majority of cervical cancers occur in women who have not participated, and this is a more powerful predictor than any biological factor.
Symptoms are the weakest part of this cancer’s story, because early disease and precancerous change typically produce none. A woman can have high-grade precancerous changes, or early invasive cancer, and feel entirely well. This is the entire rationale for screening a healthy population.
When symptoms do appear, the most common is abnormal vaginal bleeding—particularly after intercourse, which is a classic presentation, as well as between periods, after menopause, or as heavier or longer periods. Persistent vaginal discharge, sometimes watery, blood-stained, or unpleasant-smelling, is common. Pelvic pain and pain during intercourse occur.
More advanced disease produces persistent pelvic or lower back pain, often extending down the legs; leg swelling from lymphatic or venous obstruction; urinary symptoms including difficulty passing urine or blood in the urine; changes in bowel habit; and general symptoms including weight loss and fatigue. Kidney impairment can result from the ureters becoming obstructed as disease extends sideways in the pelvis.
A point worth stating clearly: symptoms warrant assessment even in a woman who has been screened regularly and had normal results. Screening substantially reduces risk but does not eliminate it, and attributing postcoital bleeding to a recent normal smear is a recognised route to delayed diagnosis.
Screening and diagnosis follow a well-established pathway, though the details vary by country.
Screening has undergone a significant change. Cytology—the smear test, examining cells for abnormality—was the foundation for decades and reduced incidence dramatically. Many countries have now moved to primary HPV testing, which checks for the presence of high-risk virus rather than for abnormal cells. It is more sensitive, detects more of the changes that matter, and because a negative HPV test confers reassurance for a longer period, it allows screening intervals to be extended safely. Self-sampling, where a woman takes her own vaginal sample, has been shown to be accurate and is increasingly offered to improve participation among women who do not attend for conventional screening.
Colposcopy is performed after an abnormal screening result. The cervix is examined under magnification after applying solutions that highlight abnormal areas, and targeted biopsies are taken.
Treatment of precancerous change is usually by loop excision, removing the affected transformation zone with a fine wire loop, or occasionally by ablation. These are outpatient procedures, highly effective, and preserve the uterus and fertility, though excision is associated with a small increase in the risk of preterm birth in later pregnancies—a consideration that influences how aggressively low-grade changes in young women are treated.
Where cancer is diagnosed, staging determines treatment. Examination assesses local extent. MRI of the pelvis is the reference standard for local staging, defining tumour size, depth of invasion, extension into the surrounding parametrial tissue, involvement of the vagina, bladder, or rectum, and enlarged lymph nodes. PET-CT assesses lymph nodes and distant spread and is central to radiotherapy planning. Staging systems now formally incorporate imaging and pathological findings alongside clinical examination, replacing the older purely clinical approach.
Important to Know
The defining feature of cervical cancer is that it is preventable, and the two interventions that prevent it are among the most effective in cancer medicine. Care is coordinated by gynaecological oncology teams, with colposcopy services, radiology, radiation and medical oncology, and specialist nursing.
HPV vaccination prevents the infection that causes nearly all cases. It is most effective when given before exposure to the virus, which is why programmes target children in early adolescence, and it is now offered to boys as well as girls in many countries, both to protect them from HPV-related cancers and to reduce transmission. Real-world data have been striking: in populations with high vaccination coverage, rates of high-grade precancerous change have fallen substantially, and studies have now demonstrated marked reductions in invasive cervical cancer itself among vaccinated cohorts. Vaccination is also offered to some older individuals and to specific higher-risk groups. Importantly, vaccination does not replace screening, since the vaccines do not cover every high-risk type and many women were vaccinated after potential exposure.
Screening detects change years before cancer develops. The most consequential fact about screening is that most cervical cancers occur in women who have not been screened. Barriers are well documented—embarrassment, discomfort, previous negative experiences, cultural factors, practical difficulties attending, and a history of trauma that makes the examination distressing. These are legitimate and addressable. Self-sampling options, longer appointment times, trauma-informed approaches, and the ability to request a female clinician all help, and it is entirely reasonable to ask for adjustments rather than avoid the test.
Treatment of precancerous change prevents cancer and preserves fertility. Loop excision is a brief outpatient procedure with high cure rates. Follow-up afterwards, usually with an HPV test, confirms that treatment has worked, and this follow-up matters because a proportion of women have persistent or recurrent change.
For invasive cancer, treatment depends on stage. Very early disease may be managed with cone excision or simple hysterectomy. Fertility-sparing surgery in the form of trachelectomy, removing the cervix while preserving the uterus, is possible for carefully selected women with small early tumours who wish to have children, with subsequent pregnancies managed as higher risk.
Early-stage disease requiring radical surgery involves removal of the uterus, the surrounding parametrial tissue, and the upper vagina, with lymph node assessment. One point deserves specific mention because it reversed previous practice: a randomised trial found that minimally invasive radical hysterectomy produced worse survival than open surgery for early cervical cancer, and open surgery consequently became the recommended approach in this particular setting. This is unusual—minimally invasive surgery is preferred in most other gynaecological cancers—and it is a reasonable question to raise when discussing surgical options.
Locally advanced disease is treated with chemoradiotherapy rather than surgery, combining external beam radiotherapy, chemotherapy given alongside it to increase its effectiveness, and brachytherapy delivering radiation internally directly to the tumour. Brachytherapy is an essential component, and outcomes are meaningfully worse without it, so access to a centre that provides it matters. Treatment is intensive but is given with curative intent, and many women with locally advanced disease are cured.
Advanced and recurrent disease has changed substantially with the addition of immunotherapy, which has improved survival when combined with chemotherapy and is also used in the recurrent setting, alongside targeted antiangiogenic treatment and newer antibody-drug conjugates.
The consequences of treatment deserve honest attention. Radiotherapy causes vaginal narrowing and dryness, affecting sexual function, and vaginal dilators and topical treatment are a standard part of aftercare rather than an optional extra. Ovarian function is lost with radiotherapy or removal of the ovaries, causing menopause in younger women, and ovarian transposition—surgically moving the ovaries out of the radiation field—can preserve function in selected cases. Bowel and bladder effects, lymphoedema, and fertility loss are all significant, and hormone replacement is usually appropriate for younger women after treatment. These issues are as important to long-term quality of life as cancer control and warrant active management.
Fertility preservation should be discussed before treatment wherever it could be relevant, including egg or embryo freezing and ovarian transposition.
Follow-up involves clinical review with attention to symptoms, particularly bleeding, discharge, and pain, with imaging used according to risk and symptoms rather than routinely in all protocols.
Care is coordinated by gynaecological oncology, and treatment at centres with appropriate expertise—particularly for radical surgery and for brachytherapy—is associated with better outcomes. Examination, imaging, pathology, and clinical findings are interpreted together alongside a woman’s age, fertility wishes, and priorities.
Patient education plays an important role. Understanding that cervical cancer is caused by a common virus rather than anything a woman did wrong, that HPV infection is extremely common and usually harmless, that vaccination and screening prevent the great majority of cases, that precancerous change is not cancer and is treatable, that symptoms warrant assessment even after normal screening, and that the effects of treatment on sexual function and menopause can be actively managed all contribute to appropriate care.
Red flag symptoms include bleeding after intercourse; bleeding between periods or any bleeding after menopause; persistent, watery, blood-stained, or offensive-smelling vaginal discharge; persistent pelvic or lower back pain, particularly radiating into the legs; pain during intercourse; new leg swelling; difficulty or pain passing urine, or blood in the urine; a change in bowel habit or bleeding from the back passage; unexplained weight loss or fatigue; and any of these symptoms regardless of a recent normal screening result. These warrant prompt medical evaluation and examination of the cervix.