Martine Piccart, MD, PhD, Professor of Oncology at the Université Libre de Bruxelles, Belgium, and President of the European Cancer Organisation, said she found it “distressing” to see such large variations in 5-year survival across European countries.

“I would like to stress the fact that these cancer registries are incredibly important, but they are not sufficiently funded in many, many countries. So the data that the scientists there are able to put together are very often not standardized from one cancer registry to another, not detailed enough to allow full understanding of the reasons behind the variations,” said Dr. Piccart, speaking at a press briefing she moderated.

“We need to get the message out about how important it is to support cancer registries. This is the only way we can monitor how well or how poorly we are treating cancer patients,” she added.

A Note of Caution

Formal discussant of this study, Philippe Autier, MD, of the University of Strathclyde Institute of Global Public Health, Lyon, France, had some concerns about the report. “I would like to inject a note of caution. We need to consider the complexity of the concept of survival. Many factors influence incidence and cancer-related mortality. Survival is a conglomerate between mortality and incidence.”

“Overdiagnosis makes a huge difference in incidence of common cancers—mainly breast, prostate, thyroid cancers, and melanoma. These increases are mainly at early stages, many of which would not become clinically apparent during the patient’s lifetime,” Dr. Autier told listeners. “We should bear this in mind when interpreting cancer survival statistics, particularly for these cancers where screening plays a role.”

In hematologic cancers, screening is not associated with overdiagnosis. In colorectal, cervical, and pancreatic cancers, the risk of overdiagnosis is minimal.

Survival is specific to stage at diagnosis. There are changes in stage over time, great variability in staging procedures between and within medical institutions. These factors can affect reporting of survival, Dr. Autier said. ■

Disclosure: Dr. Piccart has a consulting or advisory role with Amgen, Astellas Pharma, AstraZeneca, Bayer, Invivis, Lilly, MSD, Novartis, Pfizer, Roche/Genentech, Sanofi, Symphogen, Synthon, and Verastem; and honoraria from Amgen, Astellas Pharma, AstraZeneca, Bayer, Invivis, Lilly, MSD, Novartis, Pfizer, Roche/Genentech, Sanofi, Symphogen, Synthon, and Verastem. Dr. Autier reported no potential conflicts of interest.