During the 1970s, which type of therapy was found to improve response rates and survival without significantly increasing toxicity?

• A. Radiation
• B. Bone marrow transplant
• C. Biologic response modifiers
• D. Combination chemotherapy

Answer: (D)

Combining several chemotherapy drugs with different mechanisms is the approach that boosted overall cancer control in the 1970s. Using multiple agents allows a broader attack on cancer cells, hitting them at different points in their growth and survival processes. Trials from that era showed higher response rates and longer survival with these regimens than with single-agent therapy, and the toxicity could be kept acceptable because the drugs’ side effects don’t completely overlap and are carefully scheduled and dosed. This strategy also helps curb resistance by presenting cancer cells with multiple insults they must adapt to, and it addresses micrometastatic disease throughout the body, something local therapies can’t do.

Other options don’t fit as well. Radiation is a local treatment and doesn’t routinely improve systemic survival. Bone marrow transplant carries substantial risk and, at the time, did not consistently translate into better survival across many cancers. Biologic response modifiers emerged later and often added toxicity without the same clear survival gains in that era.