Cervical cancer is a malignancy that begins in the cervix — the lower part of the uterus that connects to the vagina. Nearly all cervical cancers are caused by persistent infection with high-risk strains of human papillomavirus (HPV). Widespread screening with Pap tests and HPV vaccination have dramatically reduced cervical cancer incidence and mortality in developed countries, making it one of the most preventable of all cancers.
Cervical cancer is the third most common gynecologic malignancy in the United States, behind endometrial cancer and ovarian cancer. Its staging and surgical planning rely heavily on MRI — particularly for the critical determination of parametrial involvement, which is the single most important factor separating surgical candidates from those who require primary chemoradiation. Conditions that produce abnormal vaginal bleeding or pelvic pain — including uterine fibroids and adenomyosis — can overlap clinically with early cervical cancer, reinforcing the importance of regular Pap and HPV screening to detect malignancy before symptoms develop.
Causes
Human papillomavirus (HPV) infection.
Persistent infection with high-risk strains of HPV is responsible for approximately 99% of all cervical cancers — the most direct causal link between a virus and a human cancer identified in medicine. HPV types 16 and 18 together account for approximately 70% of cervical cancers; type 16 is the dominant cause of squamous cell carcinoma, while type 18 is more strongly associated with adenocarcinoma. Most HPV infections are transient and cleared by the immune system within 1–2 years without causing disease. Persistent infection — particularly in women who are immunosuppressed — allows the virus to integrate into the host genome and disrupt the p53 and Rb tumor suppressor pathways, leading to uncontrolled cervical epithelial proliferation, progression through increasingly severe grades of cervical intraepithelial neoplasia (CIN 1 ? CIN 2 ? CIN 3), and ultimately invasion through the basement membrane into invasive carcinoma. This progression typically takes 10–15 years, creating a long window for screening-based detection and precancerous treatment.
Other risk factors.
Cigarette smoking approximately doubles the risk of squamous cell cervical cancer — tobacco carcinogens are concentrated in cervical mucus and directly damage DNA. Immunosuppression from HIV infection, organ transplantation, or immunosuppressive medications significantly elevates risk and accelerates the HPV ? cancer progression timeline. Long-term oral contraceptive use (over 5 years) modestly increases risk, likely by promoting HPV persistence. Multiple sexual partners and first sexual activity at a young age increase cumulative HPV exposure. A family history of cervical cancer reflects shared HPV exposure patterns and possibly genetic susceptibility to persistent infection. Lack of regular Pap and HPV screening is the single greatest risk factor for developing invasive disease — most cervical cancers occur in women who are unscreened or underscreened, making access to gynecologic care a critical public health determinant.
Symptoms
Early cervical cancer is typically asymptomatic — the cancer is growing within the cervical stroma before it reaches the mucosal surface or invades adjacent structures — which is precisely why routine screening with Pap and HPV co-testing is essential and life-saving. When symptoms do occur, the most important is abnormal vaginal bleeding: intermenstrual bleeding, postcoital bleeding (bleeding after intercourse, which reflects friable tumor surface), or postmenopausal bleeding. Unusual or malodorous vaginal discharge reflects tumor necrosis and ulceration. Pelvic pain and pain with intercourse develop as the tumor enlarges or invades the parametria. Advanced disease causes leg edema (lymphatic or venous obstruction), hydronephrosis with flank pain (ureteral obstruction at the pelvic sidewall — a Stage III finding), and back pain or sciatica from sacral nerve involvement.
Diagnosis
Cervical cancer screening uses the Pap test (cytologic evaluation of exfoliated cervical cells) and HPV co-testing. Abnormal screening results prompt colposcopy — direct magnified examination of the cervix with acetic acid application to highlight abnormal acetowhite lesions — and directed biopsy of suspicious areas. The definitive diagnosis is histologic, established by biopsy. LEEP (loop electrosurgical excision procedure) or cold knife cone biopsy may be performed both diagnostically and therapeutically for high-grade precancerous lesions.
An MRI of the pelvis is the primary staging imaging study once invasive cancer is confirmed. MRI provides critical information that clinical examination alone cannot reliably determine: tumor size (the 4 cm threshold separates Stage IB1/IB2 from IB3), depth of invasion into the cervical stroma, extension into the upper vagina or uterine body, and — most critically — parametrial invasion (disruption of the low-signal fibrous ring surrounding the cervix on T2-weighted MRI), which defines Stage IIB and precludes surgical resection with clear margins. DWI (diffusion-weighted imaging) improves detection of nodal metastases and primary tumor delineation. MRI is also used to plan and monitor brachytherapy boost delivery. CT of the chest, abdomen, and pelvis is added to assess for nodal and distant metastatic disease. PET-CT is increasingly used for lymph node staging in locally advanced disease.
Classification (FIGO staging)
Cervical cancer is staged clinically and radiographically using the FIGO system. MRI provides the preoperative staging information that drives the surgery vs. chemoradiation treatment decision.
- Stage I: Cancer confined to the cervix. Stage IA tumors are microscopic; Stage IB tumors are clinically visible. IB1 (<2 cm), IB2 (2–4 cm), and IB3 (>4 cm) have different surgical and radiation implications.
- Stage II: Cancer beyond the cervix but not reaching the pelvic wall or lower vagina. IIA involves the upper vagina without parametrial invasion; IIB involves the parametria — the critical MRI finding that changes treatment from surgery to chemoradiation.
- Stage III: Cancer reaching the pelvic sidewall, lower third of the vagina (IIIA), or causing ureteral obstruction and hydronephrosis (IIIC). IIIC includes lymph node involvement — pelvic (IIIC1) or para-aortic (IIIC2).
- Stage IV: Cancer involving the bladder or rectal mucosa (IVA) or distant metastatic spread including peritoneum or supraclavicular nodes (IVB). Systemic treatment is the primary modality.
Histologically, approximately 70% of cervical cancers are squamous cell carcinomas arising from the transformation zone; adenocarcinomas account for most of the remainder and are increasing in relative frequency as squamous cancers are prevented by screening.
Treatments
Treatment is stage-dependent and critically determined by the MRI finding of parametrial involvement — the watershed between surgical and radiation-based primary treatment.
Early-stage disease (Stage IA–IB2, no parametrial invasion): Surgical resection is the preferred treatment for medically fit patients. Microinvasive tumors (Stage IA1 without lymphovascular invasion) can be treated with cone biopsy alone, preserving the uterus. For Stage IB1–IB2, radical hysterectomy with bilateral pelvic lymph node dissection (Wertheim hysterectomy) is the standard — the parametria, upper vagina, and uterosacral ligaments are removed en bloc with the uterus. Minimally invasive approaches have largely been supplanted by open surgery following data showing inferior oncologic outcomes with laparoscopic radical hysterectomy for cervical cancer. For women wishing to preserve fertility with tumors under 2 cm, radical trachelectomy (removing the cervix and parametria while preserving the uterine body) with cerclage placement is a validated fertility-sparing option at specialized centers.
Locally advanced disease (Stage IB3–IVA).
Concurrent platinum-based chemotherapy (cisplatin) and external beam radiation therapy followed by intracavitary brachytherapy boost to the cervix is the standard of care for locally advanced cervical cancer. MRI-guided adaptive brachytherapy — in which the brachytherapy applicator position and dose distribution are optimized based on serial MRI scans — has significantly improved local tumor control while reducing radiation dose to the bladder and rectum. Recent data support adding bevacizumab (anti-VEGF) to concurrent chemoradiation in selected patients with locally advanced disease.
Advanced or recurrent disease.
Carboplatin/paclitaxel with bevacizumab is the standard first-line chemotherapy regimen for metastatic or recurrent cervical cancer. Pembrolizumab (anti-PD-1) is now incorporated into first-line treatment for PD-L1 positive tumors, reflecting the responsiveness of HPV-related cancers to immune checkpoint blockade. Pelvic exenteration — an extensive surgical procedure removing the uterus, vagina, bladder, and/or rectum — is considered for centrally recurrent disease after prior radiation in highly selected patients.
Prevention.
Cervical cancer is one of the most preventable cancers. HPV vaccination with the 9-valent vaccine (Gardasil 9), ideally before first sexual activity in both girls and boys aged 9–12, prevents infection with the seven highest-risk HPV types and is projected to eliminate the majority of cervical cancers in vaccinated cohorts. Regular cervical cancer screening — Pap test alone every 3 years, or Pap plus HPV co-test every 5 years — remains essential for unvaccinated women and for vaccinated women until long-term data confirm durability of protection. Smoking cessation and prompt colposcopic evaluation and treatment of high-grade precancerous lesions (CIN 2/3) complete the prevention strategy.
Get an MRI to Confirm Your Diagnosis
Before surgical planning or starting treatment, a clear MRI diagnosis ensures the right path forward. First Look MRI offers self-pay Pelvis MRI scans — no doctor's order or insurance required — at our locations in Georgia, Texas, and Colorado.