Scientific Studies Don't Always Tell the Whole Story

Every day (or so it seems), there is a report about a new scientific finding about what causes or cures cancer (or other illness). It's all too easy to get your hopes up, so it's important to understand how to evaluate studies.

According to the American Institute of Cancer Research (AICR), scientific studies provide clues to deciphering the mysteries of cancer. But for us consumers, reading about these medical findings can be a mystery.

Sussing Out the Science

There are many types of studies and each has strengths and weaknesses.

Studies conducted in a lab, rather than with people, are very preliminary; don't expect them to translate into clinical practice in the near future. Observational and epidemiological (research on disease features in a population) studies can be useful as a starting point, but drawing firm conclusions from such studies is premature. While it's not perfect, the randomized (in which study participants are selected at random), controlled (subjects include both people who are receiving treatment and a control group, who are not), double blind (neither the participants nor the investigators know which subjects are receiving treatment) trial is considered the scientific gold standard.

The experts at, which reviews media coverage of healthcare stories, offer tips for consumers trying to evaluate health-related stories:

  • Be skeptical of results that are based on a single study.
  • If a new drug may, could, or should be approved by the FDA, don't put too much stock in the prediction. The medication may never be approved or available.
  • Observational studies cannot provide evidence of cause and effect, only evidence of some relationship between exposure to something (e.g. a drug) and outcome. A stronger study design should explore the association in more depth. Until then, any link between cause and effect in observational studies is purely speculative.
  • Consumers should be cautious if they see these words in a health story: cure, miracle, breakthrough, promising, dramatic, hope, or victim.

One area of cancer research the media frequently covers is the association between food and cancer risks or benefits. Several researchers evaluated 35 years of studies involving a random collection of foods that claimed risks or benefits. Their conclusion: "There is strong evidence, and pretty strong expectations, that some nutrients in some foods would be related to cancer risk—either protective or increased risk—but it's very hard to believe that almost anything would be associated with cancer."

Gary Schwitzer of says in order to become well-informed consumers, "we must be willing to accept the limitations of science and be open to shared decision making that recognizes that there are tradeoffs in any decision made in this uncertain and unpredictable place we call reality."

What you can do: By keeping up with research on your type of cancer, you will become an informed—but skeptical—patient and healthcare consumer. Talk to your physician about study results that might affect you.

Liesa Harte, MD, reviewed this article.




Pittman, Genevra. "Treat Nutrition and Cancer Research Cautiously: Study." Reuter's Health. Web. 5 December 2012.

American Institute for Cancer Research. "The Expert Report." Web. Published March 10, 2014.

American Institute for Cancer Research. "Studying Cancer: Learn How Scientists Research Diet and Cancer." Web. Published June 28, 2011. "Tips for Understanding Studies." Web. Page accessed September 2, 2014. 

Bottles, Kent, MD. "The Difficult Science Behind Becoming a Savvy Healthcare Consumer, Part I." Blog. Web. 24 December 2010.