The FIGO staging for ovarian cancer is a systematic approach to determining the extent of the disease based on selected clinical criteria. This calculator assists in identifying the appropriate FIGO stage, a critical step in evaluating disease progression and planning treatment strategies.

The process begins with a user selecting the criterion that best describes the condition of the ovarian tumor from a predefined set. These criteria encompass various scenarios, such as whether the tumor is limited to one or both ovaries, the involvement of the tumor surface, presence of malignant cells in ascites or peritoneal washings, surgical spills, capsule ruptures, and the extent of tumor spread or metastasis.

Once a criterion is chosen, the calculator identifies the corresponding FIGO stage. The possible scenarios and their resulting stages include:

- Tumor limited to 1 ovary without further complications is classified as Stage IA.
- Extension to both ovaries under the same conditions marks Stage IB.
- If there is an intraoperative surgical spill, the stage advances to IC1.
- Pre-surgical capsule rupture or surface tumor presence appoints the tumor to Stage IC2.
- Detection of malignant cells in ascites or washings results in Stage IC3.
- Pelvic extension and/or implants in nearby structures like the uterus or fallopian tubes define Stage IIA.
- Tumor's extension to other pelvic intraperitoneal tissues reflects Stage IIB.
- For tumor spread confirmed outside the pelvis with lymph node involvement up to 10 mm, the stage is IIIA1(i).
- If lymph nodes exceed 10 mm, it categorizes as Stage IIIA1(ii).
- Microscopic extrapelvic peritoneal involvement leads to Stage IIIA2.
- Macroscopic peritoneal metastases beyond the pelvic brim that measure up to 2 cm indicate Stage IIIB.
- Sizes over that threshold denote Stage IIIC.
- Distant metastases, excluding peritoneal metastasis, and pleural effusion with positive cytology correspond to Stage IVA.
- If metastases extend to extra-abdominal organs, including inguinal lymph nodes, the tumor is assigned Stage IVB.

This structured method of defining the FIGO stage based on specific criteria provides clinicians with a standardized framework, allowing for effective communication and coordinated treatment planning across medical teams. It ensures that the nuances of tumor spread are adequately captured and appropriately staged according to recognized standards.

The FIGO staging for ovarian cancer is a clinical tool designed for the classification and stratification of ovarian cancer severity. This system is crucial for determining the appropriate treatment strategy and for predicting patient prognosis. 

The primary components of this staging system are based on the extent of the tumor, its spread to other parts of the body, and the presence of malignant cells in the ascites or peritoneal washings. The staging ranges from Stage IA, where the tumor is limited to one ovary without any malignant cells in the ascites or peritoneal washings, to Stage IVB, which indicates distant metastasis excluding peritoneal metastasis and metastases to extra-abdominal organs.

The FIGO staging for ovarian cancer takes into account whether the tumor is limited to one or both ovaries, the presence of surgical spill intraoperatively, capsule rupture before surgery, or tumor on the ovarian surface. It also considers the presence of malignant cells in the ascites or peritoneal washings, pelvic extension and/or implants on the uterus, fallopian tubes, or ovaries, and the spread to other pelvic intraperitoneal tissues. The system also includes stages for cytologically or histologically confirmed spread to the peritoneum outside the pelvis and/or metastasis to the retroperitoneal lymph nodes, as well as microscopic or macroscopic extrapelvic peritoneal involvement.

The FIGO staging for ovarian cancer is a comprehensive system that provides a detailed assessment of the disease's extent, which is essential for guiding treatment decisions and estimating patient prognosis.