Ovarian cancer

Risk is increased in nulliparous women and reduced by pregnancy 

Localized ovarian cancer is usually asymptomatic and detected on routine pelvic examination as a palpable non tender adnexal mass.

OVARIAN CANCER

INCIDENCE AND EPIDEMIOLOGY 

Annually in the United States about 25,000 new cases are found and nearly 16,000 women die of ovarian cancer.Incidence begins to rise in the fifth decade ,peaking in the eight decade.Risk is increased in nulliparous women and reduced by pregnancy ( risk decreased about 10% per prgnancy ) and oral contraceptives.About 5% of cases are familial.

GENETICS

Mutations in BRCA-I predispose women to both breast and ovarian cancer.Cytogenetic analysis of epithelial ovarian cancers that are not familial often reveals complex karyotypic abnormalities including structural lesions on chromosomes I and II and loss of heterozygosity for loci on chromosomes 3q ,6q ,11q ,13q and 17q .C-myc ,H-ras ,K-ras and HER2/neu are often mutated or overexpressed.Unlike colon cancer ,a stepwise pathway to ovarian carcinoma is not apparent.

SCREENING

No benefit has been seen from screening women of average risk.Hreditary ovarian cancer accounts for 10% of all cases.Women with BRCA-I or -2 mutations should consider prophylactic bilateral salpingo-oopherectomy by age 40.

CLINICAL PRESENTATION

Most patients present with abdominal pain ,bloating ,urinary symptoms ,and weight gain indicative of disease spread beyond the true pelvis.Localized ovarian cancer is usually asymptomatic and detected on rotine pelvic examination as a palpable non tender adnexal mass.Most ovarian masses detectedincidentally in ovulating women are ovarian cysts that resolve over one to three menstrual cycles.Adnexal masses in postmenopausal women are more often pathlogic and should be surgically removed.Ca-125 serum levels are equal or >35 U/ml in 80-85% of women with ovarian cancer,but other conditions may also cause elevations.

PATHOLOGY

Half of ovarian tumors are benign,one third are malignant and the rest are tumors of low malignant potential.These borderline lesions have cytologic features of malignancy but do not invade.Malignant epothelial tumors may be of five different types : serous ( 50% ) ,mucinous (25% ) ,endometroid (15%) ,clear cell (5% ) ,and Brenner tumors ( 1% ,derived from urothelial or transitional epithelium ).The remining 4% of ovarian tumors are stromal or germ cell tumors,which are managed like testicular cancer in men .

Histologic grade is an important prognostic factor for the epithelial varieties.

STAGING

Extent of disease is ascertained by a surgical procedure that permits visual and manual inspection of all peritoneal surfaces and the diaphragm.Total abdominal hysterectomy ,bilateral salpingo-oopherectomy ,partial omenectomy ,pelvic and paraaortic lymph node sampling ,and peritoneal washings should be performed .

INVESTIGATIONS

Pelvic examination should be complmented by a transvaginal ultrasound and serum CA 125 .Magnetic response imaging is currently the bet imaging technique for the pelvis.

TREATMENT

Surgery  (with total abdominal hysterectomy ,bilateral salpingo-oophorectomy and omentectomy ) has a major role in the treatment of ovarian cancer in all stages .For patients in whom the disease is confined to the ovary , the surgery can be curative in 80-90% if the histology is well to moderately differentiated.For patients with poorly differentiated or more advanced disease ,with spread throughout the peritoneal cavity ,surgery still has a major role in staging the patient and improving survival ,as it has been shown that the response to chemotherapy ,and survival ,is much enhanced if the tumour is able to be surgically debulked to leave only small amounts (>1cm ) of metastatic disease.

The most important drugs used to treat ovarian caner are cisplatin and its analogue carboplatin ,which is associated with fewer side-effects .Response is achieved in approximately two-thirds of patients.Paclitaxel has been shown to improve the survival of many patients when added to a platinum-based treatment such that the median survival following combination treatment of advanced metastatic disease is approximately 3 years .Up to 30% of those with metastatic disease may be alive after 5 years ,although this falls to 5-10% if the cancer is not able to be debulked at operation or has spread out side the peritoneal cavity.