Which of the following is NOT a characteristic of tumors that are 'in situ'?

• A. They have spread to surrounding tissues
• B. They are contained
• C. They may develop into invasive cancer
• D. They require monitoring

Answer: (A)

The concept of tumors that are 'in situ' refers to a stage of cancer where the tumor has not invaded surrounding tissues. This means that 'in situ' tumors are localized, remaining confined to the site of origin without spreading.

Since 'in situ' tumors are characterized by their containment, the option indicating that they have spread to surrounding tissues is incorrect, as it contradicts the very definition of 'in situ.' The other characteristics are indeed true: 'in situ' tumors can progress into invasive cancer if not monitored or treated, and they warrant careful observation because of this potential. Hence, the assertion that they have spread to surrounding tissues accurately identifies what is NOT a characteristic of tumors that are 'in situ.'