**Core Concept:** Breast cancer is a malignant tumor that develops from the epithelial cells of the mammary gland. It can be classified into different subtypes based on the presence of specific markers, such as hormone receptors and HER2. Modified radical mastectomy is a surgical procedure that involves removal of the entire breast, axillary lymph nodes, and sometimes the pectoral muscles. Treatment options following modified radical mastectomy depend on the subtype and stage of the cancer.

**Why the Correct Answer is Right:** In this case, a modified radical mastectomy has been performed on a 30-year-old female with unilateral breast cancer and axillary lymph node enlargement. This indicates that the cancer has spread locally and may have involved lymph nodes, necessitating a more extensive surgery. Treatment following modified radical mastectomy depends on the subtype and stage of cancer. The correct answer is "C."

**Why Each Wrong Option is Incorrect:**

A. This option is incorrect because it suggests that further treatment should be decided based on the patient's age. Age alone is not a determining factor for post-operative treatment options in breast cancer patients.

B. This option is incorrect because it advocates for adjuvant therapy based on the patient's age. Age does not dictate the need for adjuvant therapy in breast cancer patients.

D. This option is incorrect because it suggests that further treatment should be decided based on the tumor size. Tumor size is one of several factors considered in determining post-operative treatment options but cannot be the sole basis for further treatment decisions.

**Clinical Pearl:** In determining further treatment options for a patient with breast cancer following modified radical mastectomy, several factors including tumor size, subtype, lymph node involvement, and stage should be considered. Treatment decisions should not be based on age, tumor size, or age alone.

✓ Correct Answer: B. Adriamycin based chemotherapy followed by tamoxifen depending on estrogen/progesterone receptor status