Progressive disease (PD) is defined as?

• A. Appearance of tumor growth after a period of complete response
• B. At least a 50% reduction in the tumor burden without development of new tumors
• C. Absence of all signs and symptoms of tumor
• D. Greater than 25% increase in tumor burden or appearance of new tumor

Answer: (D)

Progressive disease means the cancer is getting worse on the current treatment. This is shown when the tumor burden increases by a predefined amount or when new tumor lesions appear, signaling that the therapy is no longer controlling the disease. In practice, a greater than a certain threshold of increase in existing tumor measurements (here, more than 25%) or the appearance of new tumors meets the criteria for progression. This distinguishes progression from remission (no signs of disease) or stable disease (no enough change to qualify as either response or progression).