Gynecolegy And Health Essay, Research Paper
gynecolegy and health Of all gynecologic malignancies, ovarian cancer continues to have the highest mortality and is the most difficult to diagnose. In the United States female population, ovarian cancer ranks fifth in absolute mortality among cancer related deaths (13,000/yr). In most reported cases, ovarian cancer, when first diagnosed is in stages III or IV in about 60 to 70% of patients which further complicates treatment of the disease (Barber, 3). Early detection in ovarian cancer is hampered by the lack of appropriate tumor markers and clinically, most patients fail to develop significant symptoms until they reach advanced stage disease. The characteristics of ovarian cancer have been studied in primary tumors and in established ovarian tumor cell lines which provide a reproducible source of tumor material. Among the major clinical problems of ovarian cancer, malignant progression, rapid emergence of drug resistance, and associated cross-resistance remain unresolved. Ovarian cancer has a high frequency of metastasis yet generally remains localized within the peritoneal cavity. Tumor development has been associated with aberrant, dysfunctional expression and/or mutation of various genes. This can include oncogene overexpression, amplification ormutation, aberrant tumor suppressor expression or mutation. Also, subversion of host antitumor immune responses may play a role in the pathogenesis of cancer (Sharp, 77). Ovarian clear cell adenocarcinoma was first described by Peham in 1899 as “hypernephroma of the ovary” because of its resemblance to renal cell carcinoma. By 1939, Schiller noted a histologic similarity to mesonephric tubules andclassified these tumors as “mesonephromas.” In 1944, Saphir and Lackner described two cases of “hypernephroid carcinoma of the ovary” and proposed “clear cell” adenocarcinoma as an alternative term. Clear cell tumors of the ovary are nowgenerally considered to be of mullerian and in the genital tract of mullerian origin. A number of examples of clear cell adenocarcinoma have been reported to arise from the epithelium of an endometriotic cyst (Yoonessi, 289). Occasionally, a renal cell carcinoma metastasizes to the ovary and may be confused with a primary clear cell adenocarcinoma. Ovarian clear cell adenocarcinoma (OCCA) has been recognized as a distinct istologic entity in the World Health Organization (WHO) classification of ovariantumors since 1973 and is the most lethal ovarian neoplasm with an overall five year survival of only 34% (Kennedy, 342). Clear cell adenocarcinoma, like most ovarian cancers, originates from the ovarian epithelium which is a single layer of cells found on the surface of the ovary. Patients with ovarian clear cell adenocarcinoma are typically above the age of 30 with a median of 54 which is similar to that of ovarian epithelialcancer in general. OCCA represents approximately 6% of ovarian cancers and bilateral ovarian involvement occurs in less that 50% of patients even in advanced cases. The association of OCCA and endometriosis is well documented (De La Cuesta,243). This was confirmed by Kennedy et al who encountered histologic or intraoperativeevidence of endometriosis in 45% of their study patients. Transformationfrom endometriosis to clear cell adenocarcinoma has been previously demonstrated insporadic cases but was not observed by Kennedy et al. Hypercalcemia occurs in asignificant percentage of patients with OCCA. Patients with advanced disease are moretypically affected than patients with nonmetastatic disease. Patients with OCCA are alsomore likely to have Stage I disease than are patients with ovarian epithelial cancer ingeneral (Kennedy, 348). Histologic grade has been useful as an initial prognostic determinant in some studiesof epithelial cancers of the ovary. The grading of ovarian clear cell adenocarcinoma hasbeen problematic and is complicated by the multiplicity of histologic patterns found inthe same tumor. Similar problems have been found in attempted grading of clear celladenocarcinoma of the endometrium (Disaia, 176). Despite these problems, tumorgrading has been attempted but has failed to demonstrate prognostic significance.However, collected data suggest that low mitotic activity and a predominance of clearcells may be favorable histologic features (Piver, 136). Risk factors for OCCA and ovarian cancer in general are much less clear than forother genital tumors with general agreement on two risk factors: nulliparity and familyhistory. There is a higher frequency of carcinoma in unmarried women and in marriedwomen with low parity. Gonadal dysgenesis in children is associated with a higher riskof developing ovarian cancer while oral contraceptives are associated with a decreasedrisk. Genetic and candidate host genes may be altered in susceptible families. Amongthose currently under investigation is BRCA1 which has been associated with anincreased susceptibility to breast cancer. Approximately 30% of ovarian adenocarcinomasexpress high levels of HER-2/neu oncogene which correlates with a poor prognosis(Altcheck, 375-376). Mutations in host tumor suppresser gene p53 are found in 50% ofovarian carcinomas. There also appears to be a racial predilection, as the vast majorityof cases are seen in Caucasians (Yoonessi, 295). Considerable variation exists in the gross appearance of ovarian clear celladenocarcinomas and they are generally indistinguishable from other epithelial ovariancarcinomas. They could be cystic, solid, soft, or rubbery, and may also containhemorrhagic and mucinous areas (O’Donnell, 250). Microscopically, clear cellcarcinomas are characterized by the presence of variable proportions of clear and hobnailcells. The former contain abundant clear cytoplasm with often centrally located nuclei,while the latter show clear or pink cytoplasm and bizarre basal nuclei with atypicalcytoplasmic intraluminal projections. The cellular arrangement may be tubulo acinar,papillary, or solid, with the great majority displaying a mixture of these patterns. Thehobnail and clear cells predominate with tubular and solid forms, respectively (Barber,214). Clear cell adenocarcinoma tissue fixed with alcohol shows a high cytoplasmicglycogen content which can be shown by means of special staining techniques.Abundant extracellular and rare intracellular neutral mucin mixed with sulfate andcarboxyl group is usually present. The clear cells are recognized histochemically andultrastructurally (short and blunt microvilli, intercellular tight junctions and desmosomes,free ribosomes, and lamellar endoplasmic reticulum). The ultrastructure of hobnail andclear cells resemble those of the similar cells seen in clear cell carcinomas of theremainder of the female genital tract (O’Brien, 254). A variation in patterns of histologyis seen among these tumors and frequently within the same one. Whether both tubular components with hobnail cells and the solid part with clear cellsare required to establish a diagnosis or the presence of just one of the patterns issufficient has not been clearly established. Fortunately, most tumors exhibit a mixture ofthese components. Benign and borderline counterparts of clear cell ovarianadenocarcinomas are theoretical possibilities. Yoonessi et al reported that nodalmetastases could be found even when the disease appears to be grossly limited to thepelvis (Yoonessi, 296). Examination of retroperitoneal nodes is essential to allow formore factual staging and carefully planned adjuvant therapy. Surgery remains the backbone of treatment and generally consists of removal of theuterus, tubes and ovaries, possible partial omentectomy, and nodal biopsies. Theeffectiveness and value of adjuvant radiotherapy and chemotherapy has not been clearlydemonstrated. Therefore, in patients with unilateral encapsulated lesions andhistologically proven uninvolvement of the contralateral ovary, omentum, and biopsiednodes, a case can be made for (a)no adjuvant therapy after complete surgical removaland (b) removal of only the diseased ovary in an occasional patient who may be youngand desirous of preserving her reproductive capacity (Altchek, 97). In the more adv-anced stages, removal of the uterus, ovaries, omentum, and as much tumor as possiblefollowed by pelvic radiotherapy (if residual disease is limited to the pelvis) orchemotherapy must be considered. The chemotherapeutic regimens generally involveadriamycin, alkylating agents, and cisPlatinum containing combinations (Barber, 442). OCCA is of epithelial origin and often contains mixtures of other epithelial tumorssuch as serous, mucinous, and endometrioid. Clear cell adenocarcinoma is characterizedby large epithelial cells with abundant cytoplasm. Because these tumors sometimesoccur in association with endometriosis or endometrioid carcinoma of the ovary andresemble clear cell carcinoma of the endometrium, they are now thought to be ofmullerian duct origin and variants of endometrioid adenocarcinoma. Clear cell tumors ofthe ovary can be predominantly solid or cystic. In the solid neoplasm, the clear cells arearranged in sheets or tubules. In the cystic form, the neoplastic cells line the spaces.Five-year survival is approximately 50% when these tumors are confined to the ovaries,but these tumors tend to be aggressive and spread beyond the ovary which tends to make5-year survival highly unlikely (Altchek, 416). Some debate continues as to whether clear cell or mesonephroid carcinoma is aseparate clinicopathological entity with its own distinctive biologic behavior and naturalhistory or a histologic variant of endometrioid carcinoma. In an effort to characterizeclear cell adenocarcinoma, Jenison et al compared these tumors to the most common ofthe epithelial malignancies, the serous adenocarcinoma (SA). Histologically determinedendometriosis was strikingly more common among patients with OCCA than with SA.Other observations by Jenison et al suggest that the biologic behavior of clear celladenocarcinoma differs from that of SA. They found Stage I tumors in 50% of theobserved patient population as well as a lower incidence of bilaterality in OCCA(Jenison, 67-69). Additionally, it appears that OCCA is characteristically larger thanSA, possibly explaining the greater frequency of symptoms and signs at presentation. Risk Factors There is controversy regarding talc use causing ovarian cancer. Until recently, mosttalc powders were contaminated with asbestos. Conceptually, talcum powder on theperineum could reach the ovaries by absorption through the cervix or vagina. Sincetalcum powders are no longer contaminated with asbestos, the risk is probably no longerimportant (Barber, 200). The high fat content of whole milk, butter, and meat productshas been implicated with an increased risk for ovarian cancer in general. The Centers for Disease Control compared 546 women with ovarian cancer to 4,228controls and reported that for women 20 to 54 years of age, the use of oralcontraceptives reduced the risk of ovarian cancer by 40% and the risk of ovarian cancerdecreased as the duration of oral contraceptive use increased. Even the use of oralcontraceptives for three months decreased the risk. The protective effect of oralcontraceptives is to reduce the relative risk to 0.6 or to decrease the incidence of diseaseby 40%. There is a decreased risk as high as 40% for women who have had four ormore children as compared to nulliparous women. There is an increase in the incidenceof ovarian cancer among nulliparous women and a decrease with increasing parity. The”incessant ovulation theory” proposes that continuous ovulation causes repeated traumato the ovary leading to the development of ovarian cancer. Incidentally, having two ormore abortions compared to never having had an abortion decreases one’s risk ofdeveloping ovarian cancer by 30% (Coppleson, 25-28). Etiology It is commonly accepted that cancer results from a series of genetic alterations thatdisrupt normal cellular growth and differentiation. It has been proposed that geneticchanges causing cancer occur in two categories of normal cellular genes, proto-oncogenes and tumor suppressor genes. Genetic changes in proto-oncogenes facilitatethe transformation of a normal cell to a malignant cell by production of an altered oroverexpressed gene product. Such genetic changes include mutation, translocation, oramplification of proto-oncogenes Tumor suppressor genes are proposed to preventcancer. Inactivation or loss of these genes contributes to development of cancer by thelack of a functional gene product. This may require mutations in both alleles of a tumorsuppressor gene. These genes function as regulatory inhibitors of cell proliferation, suchas a DNA transcription factor, or a cell adhesion molecule. Loss of these functionscould result in abnormal cell division or gene expression, or increased ability of cells intissues to detach. Cancer such as OCCA most likely results from the dynamic interactionof several genetically altered proto-oncogenes and tumor suppressor genes (Piver, 64-67). Until recently, there was little evidence that the origin of ovarian was genetic. Before1970, familial ovarian cancer had been reported in only five families. A familial cancerregistry was established at Roswell Park Cancer Institute in 1981 to document thenumber of cases occurring in the United States and to study the mode of inheritance. Ifa genetic autosomal dominant transmission of the disease can be established, counselingfor prophylactic oophorectomy at an appropriate age may lead to a decrease in the deathrate from ovarian cancer in such families. The registry at Roswell Park reported 201 cases of ovarian cancer in 94 families in1984. From 1981 through 1991, 820 families and 2946 cases had been observed.Familial ovarian cancer is not a rare occurrence and may account for 2 to 5% of all casesof ovarian cancer. Three conditions that are associated with familial ovarian cancer are(1) site specific, the most common form, which is restricted to ovarian cancer, and (2)breast/ovarian cancer with clustering of ovarian and breast cases in extended pedigrees
(Altchek, 229-230). One characteristic of inherited ovarian cancer is that it occurs at asigni