## **Core Concept**
The question pertains to the staging of endometrial cancer, which is primarily based on the International Federation of Gynecology and Obstetrics (FIGO) staging system. This system considers factors such as tumor size, depth of myometrial invasion, and extrauterine spread for staging.

## **Why the Correct Answer is Right**
The correct answer, **FIGO Stage IA**, is appropriate for a tumor that involves the uterine cavity more than 10 cms in length but has only early myometrial involvement. According to the FIGO staging system:
- Stage I implies the cancer is confined to the uterus.
- Stage IA is specified for tumors with no or less than half myometrial invasion.

## **Why Each Wrong Option is Incorrect**
- **Option A (FIGO Stage IC):** This stage involves more than half myometrial invasion, which does not match the description of "early myometrial involvement."
- **Option B (FIGO Stage II):** This stage involves the uterus and cervix, which is not indicated in the question stem.
- **Option D (FIGO Stage III):** This stage involves the uterus and extrauterine structures (like pelvic lymph nodes, para-aortic lymph nodes, or vagina), which is beyond the scenario described.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that the FIGO staging for endometrial cancer is primarily surgical, relying on findings from hysterectomy and lymph node dissection. Accurate preoperative evaluation, including imaging studies like MRI, helps in planning surgical approach.

## **Correct Answer:** . **FIGO Stage IA**