CANCER OF CERVIX III—EXTENSION AND METASTASES
Carcinoma of the cervix is initially a locally infiltrating cancer that spreads from the cervix to the vagina and paracervical and parametrial areas following a well-defined pattern of extension: Spread of the disease occurs primarily either through local lymphatic channels or by direct invasion of adjacent organs.
First involved are the lymphatics in the broad ligaments followed by
nodes deep in the pelvis. Rarely the inguinal nodes are involved; however, if
the lower one-third of the vagina is involved, then the median inguinal nodes
should be considered a primary node. From the original site, the malignancy may
invade and spread directly through the whole thickness of the cervix, the upper
vagina, the posterior wall of the bladder, or the anterior wall of the rectum.
Death results more frequently from the uremic complications of extensive
disease resulting in ureteral obstruction, either locally or in the
node-bearing areas described above, than from late metastases to the liver,
lungs and bones.
Cervical cancer is characterized in two ways: histologically, according
to the degree of differentiation from Grade I to Grade IV denoting increasingly
more malignant and more rapidly growing cell types and, clinically, according
to stages that indicate the demonstrable preoperative extension of the growth.
From the prognostic point of view, the histologic grading bears little
statistical relationship to 5-year survival rates after adequate therapy.
Prompt institution of treatment early in the disease is the key to a good
prognosis, and for this reason the clinical staging at time of first examination
has a direct bearing on chances of survival. The staging of cervical cancer is
as follows: stage I is tumor confined to the cervix; stage IA is microinvasion
(pre-clinical), and stage IB is all other cases confined to the cervix; in stage
IIA the tumor spreads to the upper two-thirds of the vagina, and stage IIB is
where the tumor spreads to paracervical tissue but not to the pelvic walls;
stage IIIA denotes tumor spread to the lower third of the vagina, and in stage
IIIB the tumor has spread to the pelvic wall or obstruction of either ureter by
tumor; in stage IV, tumor spread is to the mucosa of the bladder or rectum or
outside the pelvis.
Evaluation of these patients should include a chest radiograph,
intravenous pyelogram, and computed tomographic or magnetic resonance imaging
(MRI) scans to assess extent of disease and to assist in staging. (As
experience grows, MRI is displacing other imaging modalities because of its
ability to assess lymph nodes [72% to 93% accuracy] and possible tumor spread.)
Colposcopy and cervical biopsy (conization preferred) and biopsy of vaginal or
paracervical tissues may be required to
assess extent of disease. Staging is currently clinical and relies primarily on
clinical examination and the status of the ureters. For two major reasons, however,
the most accurate preoperative clinical staging can never give more than an
approximate prognosis in any individual case. First, it is clearly impossible
to gauge accurately from the physical examination and other tests whether or
not an apparently early, locally demarcated growth may not already have spread
to lymphatic channels and nodes. Second, these neoplasms show a marked individual variability in their response to radiation.
Therapy is based on stage of disease. Radical surgery is usually used for selected patients with stages I and II disease. Radiation therapy (brachytherapy, teletherapy) is used for stages IB and IIA disease or greater. Postoperative radiation therapy reduces the risk of recurrence by almost 50%. In situ carcinoma may be eradicated satisfactorily by surgery if an adequate margin of healthy tissue is excised.
