On examination of a 55-year-old woman with a 4 cm right breast lump, the mass appears fixed to the underlying pectoralis major when she tenses the muscle by pressing her hands on her hips, but slides freely over the ribs and intercostal spaces. According to the AJCC TNM classification, this physical finding:
- A Classifies the tumour as T4a
- B Classifies the tumour as T4b
- C Does not alter the T category based on size alone ✓
- D Makes the tumour inoperable by definition
Correct answer: C. Does not alter the T category based on size alone
Explanation
Only direct invasion of the chest wall proper, meaning ribs, intercostal muscles or serratus anterior, qualifies as T4a. Adherence or fixation to the pectoralis major muscle alone does not constitute chest wall invasion and does not upstage the tumour. Skin changes such as oedema or ulceration define T4b, and T4 tumours are locally advanced but not automatically inoperable.
Reference: AJCC Cancer Staging Manual, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.