Which is the lifetime cumulative dose of doxorubicin that should not be exceeded in a patient receiving cyclophosphamide as part of R-CHOP?

• A. 550 mg/m2
• B. 600 mg/m2
• C. 500 mg/m2
• D. 450 mg/m2

Answer: (D)

Doxorubicin has a dose-dependent risk of damaging the heart, so clinicians set a lifetime ceiling to protect cardiac function. The commonly used practical limit is about 450 mg/m2; some guidelines mention up to 550 mg/m2 for select patients, but 450 mg/m2 is the safer, widely cited threshold. In R-CHOP, doxorubicin is given at 50 mg/m2 per cycle for six cycles (total 300 mg/m2), which stays well below the lifetime ceiling. However, if a patient has prior anthracycline exposure or chest radiation, that remaining allowance must be considered to avoid surpassing the limit. Therefore, the lifetime cumulative dose that should not be exceeded is 450 mg/m2.