This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
The most important prognostic factor in carcinoma breast is 
Select and explain. 
A. Size of tumour, B. Skin involvement, C. Axillary gland involvement, D. Involvement of muscles
C: Axillary gland involvement
Answer: C: Axillary gland involvement 
Explanation: The Nottingham prognostic index (NPI) is used to determine prognosis following surgery for breast cancer. 
Its value is calculated using three pathological criteria: the size of the lesion; the number of involved lymph nodes; and the grade of a tumour.
Size of the lesion is least important.
The extent of axillary lymph node involvement by breast cancer—is the most established and reliable prognostic factor for subsequent metastatic disease and survival