## Core Concept
The International Federation of Gynecology and Obstetrics (FIGO) staging system is used to classify the extent of spread of ovarian cancer. The staging is based on surgical findings and histopathology. Surgical spill during the operation does not affect the FIGO staging.

## Why the Correct Answer is Right
The FIGO staging for ovarian cancer is as follows: Stage I - tumor limited to ovaries; Stage II - tumor involves one or both ovaries with pelvic extension; Stage III - tumor involves one or both ovaries with histologically confirmed peritoneal implants outside the pelvis and/or regional lymph node metastasis; Stage IV - distant metastasis. A surgical spill during the operation does not change the tumor's original stage because it is not considered as an implantation that alters the prognosis or treatment plan significantly.

## Why Each Wrong Option is Incorrect
* **Option A:** Incorrect because it suggests that a surgical spill would downstage the tumor, which is not the case according to FIGO guidelines.
* **Option B:** Incorrect as it implies an upgrade due to spill, which does not align with FIGO staging principles.
* **Option D:** Incorrect because it suggests the spill directly correlates with a more advanced stage, which is not accurate.

## Clinical Pearl / High-Yield Fact
A critical point to remember is that while surgical spill does not change the FIGO stage, it is generally recommended to avoid spill during surgery to prevent potential dissemination of tumor cells. However, the FIGO staging system focuses on the extent of disease present before and after the surgical intervention, not the technical aspects of the surgery itself.

## Correct Answer Line
**Correct Answer: C.**