OBJECTIVE: To estimate the number of deaths among cancer patients diagnosed in Great Britain that would be avoidable within 5 years of diagnosis if the mean (or highest) survival in Europe for patients diagnosed during 1985-1989, 1990-1994 and 1995-1999 were achieved. DESIGN: Five-year relative survival for cancers in Great Britain compared with that from other countries in the EUROCARE-2, -3 and -4 studies. Calculation of excess deaths (those more than expected from mortality in the general population) that would be avoidable among cancer patients in Britain if relative survival were the same as in Europe. SETTING: Great Britain (England, Wales, Scotland) and 13 other European countries. SUBJECTS: 2.8 million adults diagnosed in Britain with 1 of 39 cancers during 1985-1989 (followed up to 1994), 1990-1994 (followed up to 1999) and 1995-1999 (followed up to 2003). MAIN OUTCOME MEASURE: Annual number of avoidable deaths within 5 years of diagnosis. Percentage of the excess (cancer-related) deaths among cancer patients that would be avoidable. RESULTS: Compared with the mean European 5-year relative survival, the largest numbers of avoidable deaths for patients diagnosed during 1985-1989 were for cancers of the breast (about 18% of the excess mortality from this cancer, 7541 deaths), prostate (14%, 4285), colon (9%, 4090), stomach (8%, 3483) and lung (2%, 3548). For 1990-1994, the largest numbers of avoidable deaths were for cancers of the prostate (20%, 7335), breast (15%, 6165), colon (9%, 4376), stomach (9%, 3672), lung (2%, 3735) and kidney (22%, 2644). For 1995-1999, most of the avoidable deaths were for cancers of the prostate (17%, 5758), breast (15%, 5475), lung (3%, 4923), colon (10%, 4295), stomach (9%, 3137) and kidney (21%, 2686).Overall, some 6600-7500 premature deaths would have been avoided each year among cancer patients diagnosed in Britain during 1985-1999 if the mean survival in Europe had been achieved. This represents 6-7% of cancer-related mortality. Compared with the highest European survival, avoidable premature mortality among cancer patients fell from about 12 800 deaths a year (12.2% of cancer-related mortality) to about 11 400 deaths a year (10.6%) over the same period.A large component of the avoidable mortality is due to prostate cancer: excluding this cancer from comparison with the European mean survival reduces the annual number of avoidable deaths by 1000-1500, and the percentage of excess mortality by up to 1%. Compared with the highest survival, the annual number of avoidable deaths would be 1500-2000 fewer, and 1-2% lower as a percentage of excess mortality, but the overall trend in avoidable premature mortality among cancer patients would be similar, falling from 11.4% (1985-1989) to 10.3% (1990-1994) and 9.7% for those diagnosed during 1995-1999.For several cancers, survival in Britain was slightly higher than the mean survival in Europe; this represented some 110-180 premature deaths avoided each year during the period 1985-2003. CONCLUSIONS: Avoidable premature mortality among cancer patients diagnosed in Britain during 1985-1999 has represented 6-7% of cancer-related mortality compared with the mean survival in Europe. Compared with the highest levels of survival in Europe, the reduction from 12.2% to 10.6% of cancer-related mortality reflects small but steady progress over the period 1985-2003.