Cervical carcinoma

Carcinoma of the cervix is a malignancy arising from the cervix and is considered the third most common gynaecologic malignancy.

Epidemiology

It typically presents in younger women with the average age of onset at around 45 years.

Risk factors

• human papilloma virus - HPV (16(HPV) 16 and 18) infection: for most types except for clear cell carcinoma of the cervix and mesonephric carcinoma of the cervix
• multiple sexual partners
• early age of first sexual intercourse

Clinical presentation

Presenting symptoms include

• vaginal bleeding
• vaginal discharge
• subclinical with an abnormality detected on Pap smear screening

Pathology

Invasive cervical carcinoma is thought to arise from the transformation of cervical intraepithelial neoplasia (CIN).

Histological types

The main histological types are

• squamous cell carcinoma of the cervix: accounts for the vast majority (80-90%) of cases and is associated with exposure to human papilloma virus (HPV).
• adenocarcinoma of the cervix: rarer (5-20%) and can have several sub types which include ^11,20
  • clear cell carcinoma of the cervix
  • endometroid carcinoma of the cervix: ~7% of adenocarcinomas ²¹
  • mucinous carcinoma of the cervix
    • adenoma malignum: ~3% of adenocarcinomas
  • serous carcinoma of the cervix:
  • mesonephric carcinoma of the cervix: ~3% of adenocarcinomas ²³
• small cell carcinoma of the cervix: rare (0.5-6%) ^18,22
• adeno-squamous cell carcinoma of the cervix : rare

For a detailed overview - refer to

• WHO histological classification of tumours of the uterine cervix

Location 

Cervical carcinoma arises from the squamo-columnar junction. This is situated on the ectocervix in younger patients though regresses into the endocervical canal with age. Hence cervical tumours tend to be exophytic in younger patients and endophytic with advancing age.

Radiographic features

General features

In order to be radiographically visible, tumours must be at least stage Ib or above (see staging). MRI is the imaging modality of choice to depict the primary tumour and assess local extent. Distant metastatic disease is best assessed with CT or PET where available.

Although the FIGO staging system is clinically based, the revised 2009 FIGO staging encourages imaging as an adjunct to clinical staging. MRI can stratify patients to the optimum treatment group of primary surgery or combined chemotherapy and radiotherapy. Tumours stage IIa and below are treated with surgery.

Ultrasound

May be seen as a hypoechoic mass involving the cervix. Ultrasound does not play a role in the clinical assessment of suspected cervical carcinoma.

CT

CT in general is not very useful in assessment of the primary tumour but can be useful in assessing advanced disease. It is performed primarily to assess adenopathy but also has roles in defining advanced disease, monitoring distant metastasis, planning the placement of radiation ports, and guiding percutaneous biopsy.

On CT, the primary tumour can be hypo-attenuatinghypoattenuating or iso-attenuatingisoattenuating (~ 50 ~50% ¹⁹) to normal cervical stroma after administration of intravenous contrast material. 

PET - CT-CT

PET-CT in conjunction with pelvic MRI is widely considered to be the optimum imaging strategy to stage cervical carcinoma.  

MRI

A dedicated MRI protocol is often useful for optimal imaging assessment.

The normal low signal cervical stroma provides intrinsic contrast for the high signal cervical tumour.

• T1:  - usually iso intenseisointense compared with pelvic muscles
• T2: -
  • high signal relative to the low signal of the cervical stroma
  • hyper intensity is thought to be present regardless of histological sub type ¹

• T1 C+ (Gd) :-
  • contrast is not routinely used though maybe helpful to demonstrate small tumours considered for trachelectomy
  • on contrast-enhanced T1-weighted images, tumour presents as a high signal relative to the low signal of the cervical stroma ²⁴

MRI reporting guidelines for carcinoma of the cervix

Tumour size

The tumour should be measured in 3three orthogonal planes. Tumours with a maximum diameter greater than 4 cm are usually not amenable to primary radical surgery.

Parametrial invasion

The parametrium is the anatomical space lateral to the cervix. The reported accuracy of  MRI in detecting parametrial invasion varies in the literature from 75 to 96%.

MRI does however have a high negative predictive value in excluding parametrial invasion. If the T2 low signal cervical ring is intact then parametrial invasion is excluded.

Vaginal invasion

Replacement of the usual low signal vaginal wall with high signal tumour.:

• invasion of the upper 2/3 of the vagina =: stage IIa
• invasion of the lower 1/3 of the vagina =: stage IIIa

Pelvic sidewall involvement or hydronephrosis

Extension to the pelvic sidewall and or hydronephrosis (unless due to another cause) is consistent with IIIb disease.

Bladder and rectal invasion

MRI has a high negative predictive value at excluding bladder and rectal involvement.

Bladder involvement can be seen on MRI as thickening of the posterior bladder wall and disruption of the low signal bladder musculature or a mass within the bladder.

Rectal involvement is less common and can be seen as loss of posterior fat planes and direct tumour extension.

Staging

The FIGO staging system is a most commonly adopted. See:see cervical cancer staging 

Treatment and prognosis

 Prognosis is affected by many factors which include

• tumour stage
• volume of the primary mass
• histologic grade

Five-year survival rates vary between 92% for stage I disease and 17% for stage IV disease ¹⁸.

One of the keys roles of the radiologists is to accurately determine staging as this may lead to appropriate management pathway either with surgery or chemo-radiotherapy. At the time of writing stage II is considered as a important separator in deciding whether a case is operable or not.

Differential diagnosis

For a mass involving the cervix consider

• cervical lymphoma
• adenoma malignum - often: often considered a sub type of mucinous carcinoma of the cervix
• cervical leiomyoma
• metastases to the cervix
• invasion of the cervix from
  • primary uterine malignancy
  • vaginal cancer
• cervical ectopic pregnancy - consider: consider with women of childbearing age with a high beta HCG