Ovarian cancer is a malignant tumor originating from ovarian cells. This is actually primary ovarian cancer. Secondary ovarian cancer also affects the ovary/ovaries but it actually stems from other organs and reaches the affected ovary after blood dissemination of cancer cells (metastases).
How is Ovarian Cancer Staged?
Ovarian cancer is staged according to certain facts regarding the tumor as it is the cases with cancer of any other organ in our body. Initially, when the tumor is diagnosed there is no obvious widespread of the disease. However we cannot say for sure whether the cancer has spread and have given microscopic metastases especially if it has affected lymph and blood vessels. The goal of the surgery for ovarian cancer is to remove the tumor entirely and this way provide with tissue samples which will show the very histological type of the tumor and whether there is infiltration of lymph or blood vessels. What is more, surgery may also include removal of the regional lymph nodes and their pathohistological examination. Pathohistological examination is of vital importance for staging of any type of cancer, including ovarian cancer.
First of all, cancer of this type undergoes staging according to the AJCC/TNM System. T refers to Tumor and its extent, N refers to regional lymph Node involvement while M stands for distant Metastases.
There are several T categories with additional subcategories. Tx refers to no visible tumor because there is lack of complete information. T1 means that cancer stays localized only to one or both ovaries, while the surrounding tissues are practically intact. T2 classification includes the cancer in the ovary/ovaries and the presence of the tumor in pelvic tissues (e.g. the uterus and fallopian tubes). Cancer cells are also identified in fluid obtained after draining the pelvic cavity. T3 refers to cancer that apart from the ovary/ovaries has also spread beyond the pelvis, affecting the abdominal lining.
N categories are Nx, N0 and N1. Nx category says that description of node involvement cannot be confirmed because of lack of information. In category N0 there is no lymph node involvement while N1 refers to the presence of cancer cells in regional lymph nodes.
Finally, there are two M categories in TNM classification, M0 where there is no distant spread of cancer cells and M1 in which the tumor has spread to distant organs, some of which may be the liver, lungs etc.
When it comes to grades of ovarian tumor, this classification is specific because it shows how well developed the cancer is, which many times may influence disease progression and outcome. For instance low-grade tumors are known to give metastases in early stages of the disease while high-grade tumors are well developed rarely disseminating in initial stages of the disease.
Ovarian cancers are classified into three grades (G1, G2, G3). G1 refers to well differentiated cancer, when the cancer cells resemble normal ovarian tissue. G2 is not as well differentiated meaning that the cells are not that similar to cells normally found in the ovaries and there is G3, when cancer cells are completely atypical, which makes the tumor poorly differentiated.
Staging Categories for Ovarian Cancer
After TNM classification is achieved and the tumor's grade determined, doctors can finally stage the disease. As far as ovarian cancer is concerned, there are IV stages. These are further divided into sub-stages.
In stage I the cancer is only within ovaries and has not spread outside these organs affecting other tissues or organs in the pelvis. The examination of the washings from the abdomen or pelvis may confirm the presence of cancer cell, which basically occurs in case the tumor has been in the form of cyst that has ruptured.
Stage II is characterized by infiltration of one or both ovaries and other organs in the pelvis, most commonly the uterus and fallopian tubes although the bladder, sigmoid colon and rectum may be affected as well. There are no cancer cells in regional lymph nodes or spread of the tumor to distant organs.
In stage III ovarian cancer acts like in stage II but there is additionally spread to lymph nodes or cancer cells are found beyond the pelvis. Both of the mentioned may occur at the same time.
And finally, there is stage IV, the stage connected with progression of the disease and spread of cancer cells throughout the body. The cancer cells reach and infiltrate the liver, lungs and various other organs in the body.
Why is Staging Important?
Staging is very important for each and every type of cancer. First of all, it allows doctors to determine to what extent the tumor has grown and whether the disease is localized or disseminated.
Furthermore, staging determines the type of treatment the person will undergo. For instance, initial stages are most frequently treated surgically, while advanced stages may only be treated with chemotherapy, radiation therapy or perhaps both.
All in all, staging allows doctors to estimate the outcome of the disease i.e. whether there is hope that the patient will be cured or he/she should accept the inevitable battle with uncertain outcome.