Bone cancer statistics

Abstract

Objective To estimate how many deaths from cancer have been avoided in England and Wales because of recent improvements in survival.

Design Analysis of national statistics.

Setting England and Wales.

Subjects 1.5 million adults with diagnosis of one of 47 different cancers during 1981-5 or 1986-90.

Main outcome measures Reduction in number of cancer deaths within five years of diagnosis among patients with cancer diagnosed during 1986-90 compared with patients with cancer diagnosed during 1981-5.

Results 17 041 deaths were avoided within five years of diagnosis among patients with cancer diagnosed during 1986-90. This represents 3.3% of the cancer deaths that would have been expected if survival had been the same as for patients with cancer diagnosed during 1981-5. Two thirds of the avoided deaths arose from improvements in survival for just five cancers: female breast cancer (4822), cancers of the colon (2560), rectum (1090), and bladder (1157), and melanoma of the skin (1098). The largest proportionate reductions in excess deaths were for melanoma of the skin (23%) and cancers of the testis (17%) and bone (17%). About 12 000 (70%) of the avoided deaths arose among adults aged under 75 at death. Improvements in survival from cancers of lung, prostate, stomach, ovary, and brain were small: they accounted for 33% of all cancers but only 11% of avoided deaths.

Conclusions Small gains in survival from common cancers save more lives than larger gains for uncommon cancers. If recent rates of improvement in cancer survival continue, about 24 000 deaths within five years of diagnosis would be avoided in patents aged under 75 by the year 2010, representing about a quarter of the government's overall target of 100 000 fewer cancer deaths.

Introduction

In July 1999 the government set a target to reduce mortality from cancer in people aged under 75 in England by at least 20% by the year 2010, estimating that up to 100 000 deaths would be avoided over the next decade.[1] About half of all cancers in England arise in people under 75: in 1997, the baseline year for the target, the death rate for people under 75 was 150 per 100 000, and there were 68 400 deaths.[2] The technical supplement to the strategy suggests that improvements in cancer survival as a result of screening and better treatment would be expected to deliver about 40% of the total reduction in cancer deaths (Gina Radford, Public Health Development Unit, NHS Executive, personal communication). Cancer survival improved fairly steadily between 1971 and 1995,[3] and these survival trends can be used to estimate the potential contribution to the government's target of further gains in survival.

Subjects and methods

Trends in cancer survival up to 1995 have recently been reported for 2.9 million adults in England and Wales who had cancer diagnosed between 1971 and 1990.[3] Patients were categorised by type of cancer, sex, age at diagnosis (15-39, 40-49, 50-59, 60-69, 70-79, and 80-99 years), and deprivation category of their census enumeration district of residence at diagnosis (quintiles of the Carstairs score[4] for Great Britain around the 1981 and 1991 censuses). Relative survival up to five years after diagnosis was estimated for patients categorised by time of diagnosis (1971-5, 1976-80, 1981-5, and 1986-90) by means of a STATA algorithm based on methodology developed by Esteve et al[5] and reported for each type of cancer, sex, age at diagnosis, and deprivation category.

We carried out further analyses of these results to estimate how many cancer deaths were avoided within five years of diagnosis among patients with cancer diagnosed during 1986-90 as a result of their survival rates being higher than those of patients who had cancer diagnosed during 1981-5. We calculated avoided deaths as the difference between the observed and expected excess cancer mortality. We estimated the observed excess mortality for each type of cancer, age, and sex as the complement of the five year relative survival for patients diagnosed during 1986-90 multiplied by the total number of patients and summed over all groups. We estimated the expected excess mortality in similar fashion using the survival rates for patients diagnosed during 1981-5 (for further details, see extended description of methods on the BMJ's website).

Results

Of the 782 602 adults with one of 47 types of cancer diagnosed during 1986-90 in England and Wales, 541 976 died within five years of diagnosis. This represents 497 915 more deaths than would have been expected in the general population. An additional 17 041 cancer deaths would have been expected among these patients if there had been no improvement in cancer survival over the previous five years (see table). These deaths avoided within five years of diagnosis represent 3.3% of the overall excess mortality.

Deaths from selected cancers within five years of diagnosis among adults in England and Wales with cancer diagnosed during 1986-90, and deaths avoided due to improved survival compared with patients with cancer diagnosed in 1981-5

The largest number of avoided deaths arose for breast cancer in women (4822), representing an 11% reduction in the excess mortality that would have occurred within five years of diagnosis if survival had not improved. More than 1000 deaths were also avoided from cancers of the colon (2560, 6% of excess deaths), bladder (1157, 6%) and rectum (1090, 4%) and from melanoma of the skin (1098, 23%) (fig 1). Comparatively few deaths were avoided by improvements in survival from cancers of the lung (326 deaths, 0.2%), stomach (627, 1.6%), or prostate (294, 1%), for which survival had hardly improved since the previous five year period.

[Figure 1 ILLUSTRATION OMITTED]

The largest proportional reductions in excess deaths were for melanoma of the skin (23%) and cancers of the testis (17%) and bone (17%). For another five cancers (Hodgkin's disease and malignancies of the breast, thyroid, eye, and penis), better survival also led to a 10-12% reduction in excess deaths. For each of these cancers, five year survival for patients diagnosed during 1986-90 rose by a similar amount (3-4%) and to a figure in the range 66-72%. This led to over 4800 avoided deaths from breast cancer, but only 415 avoided deaths from the other four cancers combined, because they are much less common (table). The proportion of avoided deaths depends both on the initial survival rate and on the extent to which it improved with time. The actual number of avoided deaths also depends on the frequency of the cancer.

The pattern of avoided deaths by age at diagnosis varied widely for cancers of the breast, colon, and lung and melanoma (fig 2) (details for other cancers appear in an extra table on the BMJ's website). Three quarters (76%) of the 4822 deaths avoided among women with breast cancer arose among those aged 50-69 at diagnosis, for whom excess mortality within five years of diagnosis fell by 18-19%, proportionately about twice as much as for either younger or older patients. The increase in survival from colon cancer was similar in all age groups over 40, but more deaths were avoided in older patients, in whom the disease is much more common. For all cancers combined, about 12 000 of the 17 000 deaths avoided arose among adults aged under 75 at diagnosis (the age range targeted by government).

[Figure 2 ILLUSTRATION OMITTED]

For the less common cancers, there were too few deaths in many subgroups to obtain stable estimates of avoided deaths by sex, age, and deprivation category. For the most common cancers, adjustment for trends in age-specific survival rates within each deprivation category reduced the estimated total of avoided deaths by about 10% (data not shown).

Discussion

Cancer patients have higher mortality than the general population, but they do not all die from cancer. Improvements in cancer survival save lives, in the sense that more cancer patients will turn out to have a normal life expectancy after treatment. Improvements in survival can therefore be measured by the extent to which this excess mortality--the number of deaths among cancer patients in excess of normal mortality --falls with time.