CANCER OF CORPUS I—VARIOUS STAGES AND TYPES
Cancer of the uterine corpus usually involves malignant change of the
endometrial tissues. These are generally of the adenocarcinoma, adenosquamous,
clear cell, or papillary serous cell types. These cancers are the most frequent
malignancy of the female reproductive tract, representing the eighth leading
site of cancer-related deaths among American women.
Although the possibility of adenocarcinoma must be considered in patients suffering from abnormal bleeding during preclimacteric years, cancer of the uterine body must always be suspected with the appearance of abnormal spotting or staining from the fifth decade on. Any discharge from a normal cervix occurring in the postmenopausal age group should be regarded as highly suspicious of fundal malignancy. The discharge may at times be watery rather than frankly bloody. Pain, except in the presence of pyometrium, is not an early sign. When present, it may signify extension to other organs. Risk factors for the development of endometrial cancer include unopposed (without progestins) estrogen stimulation (such as in polycystic ovary syndrome, obesity, chronic anovulation, and estrogen replacement therapy without concomitant progestin). This may be a factor in up to 90% of cases. Selective estrogen receptor modulators with uterine activity (such as tamoxifen) may also place the patient at increased risk. Oral contraceptives reduce the risk of endometrial cancer.
If exfoliated malignant endometrial cells are found in the vaginal smear,
the diagnosis may be considered definite. (Cervical cytologic tests detect only
about 20% of known endometrial carcinomas.) Transvaginal ultrasonography or
sonohysterography may be useful (though some have raised concerns about the
possibility of extrauterine spread induced by tubal spill of fluid during
sonohysterography). The final diagnosis, however, depends inevitably upon tissue
sampling and histologic evaluation. Endometrial biopsy is approximately 90%
accurate.
In 1988, a surgical staging classification was introduced that relies on
an operative evaluation with particular emphasis on myometrial invasion in
stage I. In stage IA the tumor is limited to the endometrium; IB invasion is to
less than half of the myometrium; IC invasion is to more than half of the
myometrium. In stage IIA there is endocervical glandular involvement only; in
IIB there is cervical stromal invasion. In stage IIIA the tumor invades the
serosa and/or adnexae and/ or there is positive peritoneal cytology; in stage
IIIB there are vaginal metastases; in stage IIIC metastases to pelvic and/or
paraaortic lymph nodes have occurred. Stage IVA includes tumor invasion of the
bladder and/ or bowel mucosa, while stage IVB consists of those with distant
metastases, including intraabdominal and/or inguinal lymph nodes. Most cases
are diagnosed in stage I because of the prompt evaluation of postmenopausal
bleeding, improving the overall prognosis which is strongly dependent on the
stage of the disease: stage I disease has an approximate 90% 5-year survival,
whereas stage IV disease has a survival of less than 10%. The histologic type
is also related to prognosis, with the best prognosis associated with typical adenocarcinomas as well as better differentiated tumors with or without
squamous elements and secretory carcinomas. Approximately 80% of all
endometrial carcinomas fall into the favorable category. Poor prognostic
histologic types are papillary serous carcinomas, clear-cell carcinomas, and
poorly differentiated carcinomas with or without squamous elements.
Tumor grade and stage both affect the risk of lymph node spread in endometrial cancer. There are differences in the proportion of positive nodes between stages IB and IA cases as well as tumor grade. The frequency of nodal involvement becomes much greater with higher grade tumors and with greater depth of myometrial invasion: the risk of lymph node involvement appears to be negligible for endometrial carcinoma involving only the endometrium and for lower grade tumors with a depth of invasion involving only the inner one-third of the myometrium.
