Cancer Research and Statistics

How Statistics Make Things Look Good

Source: Trastuzumab: hopes and realities.
Lancet Oncology 3:137-144. 2002. Brian Leyland-Jones.

Trastuzumab (Herceptin) is reported to be effective and well tolerated for breast cancer. The treatment costs US$40,000.

• The research result showed that with Herceptin survival was increased by25%

Let us look at the figures critically. The median survival duration was 25 months for patients assigned chemotherapy + trastuzumab compared with 20 months for those allocated chemotherapy alone.

The increase in survival was only 5 months. It sounds better if we say 25% rather than 5 months.

• The research result showed that with Herceptin survival was increased by 45%
  

Median survival with trastuzumab + chemotherapy = 29 months

Median survival with chemotherapy only = 20 months.

Increase of survival time = 9 months. This is translated as increased survival by 45%.

• The research result showed that with Herceptin survival was increased by40%
  

Median survival with trastuzumab + paclitaxel = 25 months

Median survival with paclitaxel alone = 18 months

Increase of survival time = 7 months. This is translated as increased survival by 40%.