**Core Concept**
The prognosis of breast carcinoma is primarily influenced by the presence and extent of lymph node involvement. The axillary lymph nodes are the first site of metastasis for breast cancer cells, and their status is a critical determinant of the disease's stage and overall prognosis.

**Why the Correct Answer is Right**
The involvement of axillary lymph nodes is a key prognostic factor because it indicates the cancer's potential for spread and recurrence. The number of lymph nodes involved and the presence of metastases within these nodes are crucial in determining the cancer's stage and guiding treatment decisions. The American Joint Committee on Cancer (AJCC) staging system takes into account the axillary lymph node status, among other factors, to classify breast cancer into different stages. The presence of lymph node metastases is associated with a poorer prognosis and increased risk of recurrence.

**Why Each Wrong Option is Incorrect**
**Option A:** Oestrogen and progesterone receptor status are important prognostic factors, but they are not as predictive of overall survival as axillary lymph node status. While receptor-positive tumors may respond better to hormone therapy, the presence of lymph node metastases takes precedence in determining the cancer's stage and prognosis.
**Option C:** Clinical assessment is subjective and not a reliable method for determining the prognosis of breast carcinoma. Physical examination may detect palpable lymph nodes, but it cannot accurately assess the extent of lymph node involvement or the presence of microscopic metastases.
**Option D:** CT (Computed Tomography) scans are useful for detecting distant metastases and assessing the extent of local disease, but they are not the primary method for determining the prognosis of breast carcinoma. The presence of lymph node metastases is a more critical prognostic factor than CT findings.

**Clinical Pearl / High-Yield Fact**
The presence of 4 or more positive axillary lymph nodes is associated with a significantly poorer prognosis and is often used as an indicator for more aggressive treatment, such as chemotherapy and radiation therapy.

**✓ Correct Answer: B. Axillary lymph node status**