## **Core Concept**
The question tests the understanding of cervical cancer staging, which is primarily based on clinical examination and imaging studies. The International Federation of Gynecology and Obstetrics (FIGO) staging system is commonly used for cervical cancer staging. It takes into account the extent of the primary tumor, involvement of lymph nodes, and distant metastasis.

## **Why the Correct Answer is Right**
The patient has invasive cervical carcinoma with tumor involvement of the upper part of the vagina but no parametrial involvement. The presence of grossly enlarged pelvic and para-aortic nodes on CT scan indicates lymph node metastasis. According to the FIGO staging system, tumor extending to the upper two-thirds of the vagina without parametrial invasion is classified as Stage IIA. However, the presence of lymph node metastasis does not change the FIGO stage but is crucial for determining the prognosis and treatment plan.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Stage I is incorrect because it includes tumors confined to the cervix uteri, which is not the case here since the tumor involves the upper part of the vagina.
- **Option B:** Stage IIA is partially correct in describing the vaginal involvement but does not account for the nodal involvement explicitly in its definition; however, nodal status doesn't change FIGO staging.
- **Option C:** Stage III is incorrect because it involves tumor extension to the lower third of the vagina and/or parametrium and/or hydronephrosis or non-functioning kidney, which does not match this patient's description.
- **Option D:** Other staging systems or considerations might be mentioned here but are not relevant to FIGO.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that FIGO staging for cervical cancer is primarily clinical and based on physical examination, imaging (like IVP), and basic investigations; however, the presence of lymph node metastasis significantly affects treatment planning and prognosis.

## **Correct Answer:** .