Interesting. Though cancers that force you to fast, like stomach or esophageal cancer don't have great 5 year survival rates.
How could we know if this was survivorship bias? What if the folks who can best comply with the calorie restrictions are those who are already in a good state?
When you fold back in those 2/3 of people on that arm, the response rate is the same:
"The overall pCR rate was 11.7% and did not differ between the two groups (10.8% in FMD group versus 12.7% in control group; OR 0.830, 95% CI 0.282–2.442, P = 0.735)."