Epithelial Ovarian Cancer Is Not One Disease
Histological Subtypes Are Different Diseases
Dec 5, 2008
Epithelial ovarian carcinoma is the most common malignant ovarian tumor, representing 80% of all ovarian malignancies. It is the second most common gynecological cancer and accounts for nearly half of the deaths associated with gynecological pelvic malignancies. Epithelial ovarian cancer is thought to originate from the normal ovarian surface epithelium itself, and this is why it carries this name.
Epithelial Ovarian Cancer is a Complex Disease
Ovarian cancer is often asymptomatic where over 70% of patients with this cancer are diagnosed at an advanced stage of the disease. While up to 80% of the patients will initially respond to treatment, recurrence is generally observed within variable time intervals. Although 10-15% of the patients achieve and maintain a complete response to therapy, the remaining patients show persistent disease or eventually relapse thus requiring additional treatment. The 5-year survival rate of ovarian cancer patients is extremely low, less than 70% (for other details see also this article).
Epithelial ovarian cancer can be subdivided into different categories called histopathological subtypes. Those subtypes are heterogeneous and are designated according to their histological shapes: serous, endometrioid, mucinous, clear cell, Brenner, undifferentiated or mixed (association of two or more sub-types). The most common subtype is the serous subtype that accounts for 60% of all epithelial ovarian cancer. Oncologists have noted that different subtypes respond differently to treatment, either chemotherapy and/or surgery.
Molecular Biomarkers Help Predict Survival Time of Cancer Patients
To assess the prognosis of the disease oncologists used clinical parameters, such as stage of the disease or the amount of residual tumor after surgery, and molecular biomarkers to estimate the treatment efficacy and choose the best treatment available accordingly. Molecular biomarkers are usually proteins or genes present at a certain level in tumor specimen.
A Recent Study Shows That Each Subtype of Ovarian C`ancer Requires a Specific Biomarker
A team of Canadian researchers lead by Dr. David Huntsman from BC Cancer Agency in Vancouver has show in their recent study entitled ″Ovarian carcinoma subtypes are different diseases: implications for biomarker studies″ (PLOS Medicine, vol5, e232) that depending of the histological subtype the same biomarker has different prognostic value.
In their recent study, the researchers analyzed 21 biomarkers and their association with survival rate of 500 ovarian cancer patients representing the four main histological subtypes. Most of the biomarkers were present at different levels in the different subtypes. Nine of the 21 biomarkers were prognostic indicators when the 500 patients were considered as a group. However, when biomarkers were analyzed separately in each individual subtype, only three remained as valuable prognostic indicators for the serous subtype only.
This study highlights that ovarian cancer subtypes have distinct profiles and should be clinically considered as different diseases, and not one disease as it is currently done, with specific treatments and management.
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