Invasive squamous cell carcinoma accounts for 80% of cervical malignancies. Unlike the remainder of the reproductive tract cancers, which are more prevalent in industrialized countries, cervical cancer ranks second in cancer mortality in developing nations. Virtually all cervical cancers are associated with the human papillomavirus (HPV), which is the most common sexually transmitted infection. Squamous cancer of the cervix is unique in that it is a preventable disease when vaccination, proper screening and treatment are available and employed.
Like prostatic cancer in men (Chapter 41), cervical cancer typically arises from a precursor lesion, cervical intraepithelial neoplasia (CIN). CIN is asymptomatic and appears to precede invasive carcinoma of the cervix by 5–15 years. Almost all cervical cancer arises in the transformation zone (squamocolumnar junction) of the cervix. Here, the columnar, glandular epithelium of the endocervix meets the squamous epithelium of the ectocervix. The anatomic location of the squamocolumnar junction changes in response to a variety of factors and is different in young postpubertal girls when compared with postmenopausal women (Fig. 44.1). In older women, the transformation zone may be high in the endocervical canal. This makes the early diagnosis of cervical neoplasia more difficult.
Cervical carcinomas can spread in any one of four ways: (i) directly into the vaginal mucosa; (ii) directly into the myometrium of the lower uterine segment; (iii) into the paracervical lymphatics and from there to the obturator, hypogastric and external iliac lymph nodes; and (iv) directly into adjacent structures such as the bladder anteriorly, the rectum posteriorly, or the parametrial tissues and pelvic sidewalls laterally. Lymphatic invasion can occur even when cervical tumors are still small. Hematogenous spread and distant metastases are usually very late manifestations of the disease.
Surgical treatment is used for early-stage cervical cancers. A combination of radiation and chemotherapy is used for patients with advanced disease and in those who are poor surgical candidates.
Epidemiology of cervical cancer
The association of sexual activity with cervical cancer was first identified over 150 years ago when it was noted that the disease was rare in nuns and frequent in prostitutes. Subsequent epidemiologic data have identified the onset of sexual activity in adolescence and multiple sexual partners as high-risk characteristics for cervical cancer. Its incidence is higher in low-income women but this effect is not independent of early sexual activity and multiple sex partners. Smoking is an independent risk factor for the development of cervical cancer. Characteristics of a “high-risk” male partner include men whose previous partner developed cervical cancer, who themselves develop penile cancer or who have not had a circumcision.
Epidemiologic data suggesting that cervical cancer behaves like a sexually transmitted disease led to identification of HPV as the causative agent. Although it has been identified in over 99% of all cervical cancers, HPV infection of the cervix appears necessary but not sufficient for the development of cervical cancer. This distinction is important as cervical infection with HPV is very common; however, the majority of these infections are transient. Persistent infection with an oncogenic type of HPV confers an increased risk of developing cervical cancer.
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
