Global surveillance of cancer survival 1995-2009: analysis of individual data for 25,676,887 patients from 279 population-based registries in 67 countries (CONCORD-2)

BACKGROUND

Worldwide data for cancer survival are scarce. We aimed to initiate worldwide surveillance of cancer survival by central analysis of population-based registry data, as a metric of the effectiveness of health systems, and to inform global policy on cancer control.

METHODS

Individual tumour records were submitted by 279 population-based cancer registries in 67 countries for 25·7 million adults (age 15-99 years) and 75,000 children (age 0-14 years) diagnosed with cancer during 1995-2009 and followed up to Dec 31, 2009, or later. We looked at cancers of the stomach, colon, rectum, liver, lung, breast (women), cervix, ovary, and prostate in adults, and adult and childhood leukaemia. Standardised quality control procedures were applied; errors were corrected by the registry concerned. We estimated 5-year net survival, adjusted for background mortality in every country or region by age (single year), sex, and calendar year, and by race or ethnic origin in some countries. Estimates were age-standardised with the International Cancer Survival Standard weights.

FINDINGS

5-year survival from colon, rectal, and breast cancers has increased steadily in most developed countries. For patients diagnosed during 2005-09, survival for colon and rectal cancer reached 60% or more in 22 countries around the world; for breast cancer, 5-year survival rose to 85% or higher in 17 countries worldwide. Liver and lung cancer remain lethal in all nations: for both cancers, 5-year survival is below 20% everywhere in Europe, in the range 15-19% in North America, and as low as 7-9% in Mongolia and Thailand. Striking rises in 5-year survival from prostate cancer have occurred in many countries: survival rose by 10-20% between 1995-99 and 2005-09 in 22 countries in South America, Asia, and Europe, but survival still varies widely around the world, from less than 60% in Bulgaria and Thailand to 95% or more in Brazil, Puerto Rico, and the USA. For cervical cancer, national estimates of 5-year survival range from less than 50% to more than 70%; regional variations are much wider, and improvements between 1995-99 and 2005-09 have generally been slight. For women diagnosed with ovarian cancer in 2005-09, 5-year survival was 40% or higher only in Ecuador, the USA, and 17 countries in Asia and Europe. 5-year survival for stomach cancer in 2005-09 was high (54-58%) in Japan and South Korea, compared with less than 40% in other countries. By contrast, 5-year survival from adult leukaemia in Japan and South Korea (18-23%) is lower than in most other countries. 5-year survival from childhood acute lymphoblastic leukaemia is less than 60% in several countries, but as high as 90% in Canada and four European countries, which suggests major deficiencies in the management of a largely curable disease.

INTERPRETATION

International comparison of survival trends reveals very wide differences that are likely to be attributable to differences in access to early diagnosis and optimum treatment. Continuous worldwide surveillance of cancer survival should become an indispensable source of information for cancer patients and researchers and a stimulus for politicians to improve health policy and health-care systems.

FUNDING

Canadian Partnership Against Cancer (Toronto, Canada), Cancer Focus Northern Ireland (Belfast, UK), Cancer Institute New South Wales (Sydney, Australia), Cancer Research UK (London, UK), Centers for Disease Control and Prevention (Atlanta, GA, USA), Swiss Re (London, UK), Swiss Cancer Research foundation (Bern, Switzerland), Swiss Cancer League (Bern, Switzerland), and University of Kentucky (Lexington, KY, USA).

Radiation dose and subsequent risk for stomach cancer in long-term survivors of cervical cancer

PURPOSE

To assess the dose-response relationship for stomach cancer after radiation therapy for cervical cancer.

METHODS AND MATERIALS

We conducted a nested, matched case-control study of 201 cases and 378 controls among 53,547 5-year survivors of cervical cancer diagnosed from 1943 to 1995, from 5 international, population-based cancer registries. We estimated individual radiation doses to the site of the stomach cancer for all cases and to corresponding sites for the matched controls (overall mean stomach tumor dose, 2.56 Gy, range 0.03-46.1 and after parallel opposed pelvic fields, 1.63 Gy, range 0.12-6.3).

RESULTS

More than 90% of women received radiation therapy, mostly with external beam therapy in combination with brachytherapy. Stomach cancer risk was nonsignificantly increased (odds ratio 1.27-2.28) for women receiving between 0.5 and 4.9 Gy to the stomach cancer site and significantly increased at doses ≥ 5 Gy (odds ratio 4.20, 95% confidence interval 1.41-13.4, Ptrend=.047) compared with nonirradiated women. A highly significant radiation dose-response relationship was evident when analyses were restricted to the 131 cases (251 controls) whose stomach cancer was located in the middle and lower portions of the stomach (Ptrend=.003), whereas there was no indication of increasing risk with increasing dose for 30 cases (57 controls) whose cancer was located in the upper stomach (Ptrend=.23).

CONCLUSIONS

Our findings show for the first time a significant linear dose-response relationship for risk of stomach cancer in long-term survivors of cervical cancer.

Cancer prevalence in United States, Nordic Countries, Italy, Australia, and France: an analysis of geographic variability

BACKGROUND

The objectives of this study were to quantitatively assess the geographic heterogeneity of cancer prevalence in selected Western Countries and to explore the associations between its determinants.

METHODS

For 20 cancer sites, 5-year cancer prevalence, incidence, and survival were observed and age standardised for the mid 2000s in the United States, Nordic European Countries, Italy, Australia, and France.

RESULTS

In Italy, 5-year crude prevalence for all cancers was 1.9% in men and 1.7% in women, while it was ∼1.5% in all other countries and sexes. After adjustment for the different age distribution of the populations, cancer prevalence in the United States was higher (20% in men and 10% in women) than elsewhere. For all cancers combined, the geographic heterogeneities were limited, though relevant for specific cancers (e.g., prostate, showing >30% higher prevalence in the United States, or lung, showing >50% higher prevalence in USA women than in other countries). For all countries, the correlations between differences of prevalence and differences of incidence were >0.9, while prevalence and survival were less consistently correlated.

CONCLUSION

Geographic differences and magnitude of crude cancer prevalence were more strongly associated with incidence rates, influenced by population ageing, than with survival rates. These estimates will be helpful in allocating appropriate resources.

Breast cancer survival in the US and Europe: a CONCORD high-resolution study

Breast cancer survival is reportedly higher in the US than in Europe. The first worldwide study (CONCORD) found wide international differences in age-standardized survival. The aim of this study is to explain these survival differences. Population-based data on stage at diagnosis, diagnostic procedures, treatment and follow-up were collected for about 20,000 women diagnosed with breast cancer aged 15-99 years during 1996-98 in 7 US states and 12 European countries. Age-standardized net survival and the excess hazard of death up to 5 years after diagnosis were estimated by jurisdiction (registry, country, European region), age and stage with flexible parametric models. Breast cancers were generally less advanced in the US than in Europe. Stage also varied less between US states than between European jurisdictions. Early, node-negative tumors were more frequent in the US (39%) than in Europe (32%), while locally advanced tumors were twice as frequent in Europe (8%), and metastatic tumors of similar frequency (5-6%). Net survival in Northern, Western and Southern Europe (81-84%) was similar to that in the US (84%), but lower in Eastern Europe (69%). For the first 3 years after diagnosis the mean excess hazard was higher in Eastern Europe than elsewhere: the difference was most marked for women aged 70-99 years, and mainly confined to women with locally advanced or metastatic tumors. Differences in breast cancer survival between Europe and the US in the late 1990s were mainly explained by lower survival in Eastern Europe, where low healthcare expenditure may have constrained the quality of treatment.

The interface of population-based cancer registries and biobanks in etiological and clinical research--current and future perspectives

BACKGROUND

The availability of quality assured, population-based cancer registries and biobanks with high quality samples makes it possible to conduct research on large samples sets with long follow-up within a reasonable time frame. Defined quality for both cancer registries and biobanks is essential for enabling high quality biobank-based research. Recent networking projects have brought these infrastructures together to promote the combined use of cancer registries and biobanks in cancer research.

MATERIALS AND METHODS

In this report we review the current status and future perspectives of cancer registries and biobanks and how the interface between them should be developed to optimally further cancer research.

RESULTS AND DISCUSSION

Major conclusions for future improvements are that the research exploiting cancer registries and biobanks, and the research that is building and optimising the infrastructure, should evolve together for maximally relevant progress. Population-based and sustainable biobanks that continuously and consecutively store all samples ("Biological registries") under strict quality control are needed. There is also a need for increased education, information and visibility of the interdisciplinary sciences required for optimal exploitation of these resources.

Variation in 'standard care' for breast cancer across Europe: a EUROCARE-3 high resolution study

On a population-based sample of 13,500 European breast cancer patients mostly diagnosed in 1996-1998 and archived by 26 cancer registries, we used logistic regression to estimate odds of conservative surgery plus radiotherapy (BCS+RT) versus other surgery, in T1N0M0 cases by country, adjusted for age and tumour size. We also examined: BCS+RT in relation to total national expenditure on health (TNEH); chemotherapy use in N+ patients; tamoxifen use in oestrogen-positive patients; and whether 10 nodes were examined in lymphadenectomies. Stage, diagnostic examinations and treatments were obtained from clinical records. T1N0M0 cases were 33.0% of the total. 55.0% of T1N0M0 received BCS+RT, range 9.0% (Estonia) to 78.0% (France). Compared to France, odds of BCS+RT were lower in all other countries, even after adjusting for covariates. Women of 70-99 years had 67% lower odds of BCS+RT than women of 15-39 years. BCS+RT was 20% in low TNEH, 58% in medium TNEH, and 64% in high TNEH countries. Chemotherapy was given to 63.0% of N+ and 90.7% of premenopausal N+ (15-49 years), with marked variation by country, mainly in post-menopause (50-99 years). Hormonal therapy was given to 55.5% of oestrogen-positive cases, 44.6% at 15-49 years and 58.8% at 50-99 years; with marked variation across countries especially in premenopause. The variation in breast cancer care across Europe prior to the development of European guidelines was striking; older women received BCS+RT much less than younger women; and adherence to 'standard care' varied even among countries with medium/high TNEH, suggesting sub-optimal resource allocation.

Uveal and Conjunctival Malignant Melanoma in Denmark 1943–97: Observed and Relative Survival of Patients Followed Through 2002

PURPOSE

To evaluate the observed and relative survival of patients diagnosed with a malignant melanoma in the ocular region in Denmark during the period 1943-97.

METHODS

The study included 2,504 patients (1,292 men and 1,212 women) diagnosed with a melanoma in the ocular region, of which 2,434 cases could be topographically subclassified into 2,178 in the choroid/ciliary body, 141 in the iris, and 115 in the conjunctiva. The patients were followed through 2002 and the observed survival proportions and relative survival ratios were estimated.

RESULTS

For the total ocular region and the choroid/ciliary body, the observed survival did not vary statistically significantly with the year of diagnosis. A statistically insignificant higher observed survival for women than men was found for tumors in the ocular region and the subgroups choroid/ciliary body, iris, and conjunctiva. During the 55-year study period, the 5- and 10-year relative survival remained stable for the ocular region for men at 67% and 57% and for women at 71% and 60%, respectively, and stable for the choroid/ciliary body for men at 66% and 55% and for women at 69% and 57%, respectively. The 5- and 10-year relative survival for the iris was for men 90% and 85% and for women 99% and 101%, respectively, and for the conjunctiva for men 83% and 70% and for women 93% and 82%, respectively.

CONCLUSION

The observed and relative survival of patients diagnosed with a melanoma in the ocular region and choroid/ciliary body in Denmark during the period 1943-97 and followed through 2002 has remained stable. The highest observed and relative survival was found for iris melanomas, the lowest for choroid/ciliary body melanomas, and intermediate for conjunctival melanomas.

Second cancers after squamous cell carcinoma and adenocarcinoma of the cervix

PURPOSE

Although cervical squamous cell carcinoma (SCC) and adenocarcinoma (AC) are both caused by human papillomavirus (HPV) infection, they differ in cofactors such as cigarette smoking. We assessed whether these cofactor differences translate into differences in second cancer risk.

PATIENTS AND METHODS

We assessed second cancer risk among 85,109 cervical SCC and 10,280 AC survivors reported to population-based cancer registries in Denmark, Finland, Norway, Sweden, and the United States. Risks compared to the general population were assessed using standardized incidence ratios (SIR).

RESULTS

Overall cancer risk was significantly increased among both cervical SCC survivors (n = 10,559 second cancers; SIR, 1.31; 95% CI, 1.29 to 1.34) and AC survivors (n = 920 second cancers; SIR, 1.29; 95% CI, 1.22 to 1.38). Risks of HPV-related and radiation-related cancers were increased to a similar extent among cervical SCC and AC survivors. Although significantly increased in both groups when compared with the general population, risk of smoking-related cancers was significantly higher among cervical SCC than AC survivors (P = .015; SIR for cervical SCC = 2.07 v AC = 1.78). This difference was limited to lung cancer (SIR for cervical SCC = 2.69 v AC = 2.18; P = .026). The increased lung cancer risk among cervical AC survivors was observed for both lung SCC and lung AC. SIRs for second cancers of the colon, soft tissue, melanoma, and non-Hodgkin's lymphoma were significantly higher among cervical AC than SCC survivors.

CONCLUSION

The second cancer profiles among cervical SCC and AC survivors mirror the similarities and differences in cofactors for these two histologies. Because smoking is not a cofactor for cervical AC, the increased lung cancer risk suggests a role for additional factors.

Social inequality and incidence of and survival from malignant melanoma in a population-based study in Denmark, 1994-2003

The incidence of cutaneous malignant melanoma has increased more than that of any other cancer in most white populations during the past few decades. We investigated the effects of socioeconomic, demographic and health-related indicators on the incidence of and survival from malignant melanoma in 1994-2003 in Denmark using information from nationwide registries. The analyses were based on data on 6914 patients with malignant melanoma in a cohort of 3.22 million persons born between 1925 and 1973 and aged >or=30 years. The age- and period-standardised incidence rate was 25 and 29 per 100,000 person-years for men and women, respectively. We found an increased risk for malignant melanoma in the highest socioeconomic groups. In general, survival after a malignant melanoma was better in high socioeconomic groups and better in women than men. Our results support earlier reports that malignant melanoma is associated with higher socioeconomic position.

Risk of leukemia among survivors of testicular cancer: a population-based study of 42,722 patients

PURPOSE

The aim of this study is to quantify excess absolute risk (EAR) and excess relative risk (ERR) of secondary leukemia among a large population-based group of testicular cancer survivors.

METHODS

We identified 42,722 1-year survivors of testicular cancer within 14 population-based cancer registries in Europe and North America (1943-2002). Poisson regression analysis was used to model EAR (per 100,000 person-years [PY]) and ERR of secondary leukemia. Cumulative risks were calculated using a competing risk model.

RESULTS

Secondary leukemia developed in 89 patients (EAR = 10.8 per 100,000 PY, 95% confidence interval [CI] = 7.6-14.6; ERR = 1.6, 95%CI = 1.0-2.2). Statistically significantly elevated risks were observed for acute myeloid leukemia (AML) (EAR = 7.2, 95%CI = 4.7-10.2) and acute lymphoblastic leukemia (EAR = 1.3, 95%CI = 0.4-2.8). In multivariate analyses, AML risk was higher among patients whose initial management included chemotherapy compared to those receiving radiotherapy alone (p = 0.1). Excess cumulative leukemia risk was approximately 0.23% by 30 years after testicular cancer diagnosis.

CONCLUSIONS

Although ERR of leukemia following testicular cancer is large, EAR and cumulative risk, which are better gauges of the population burden, are small.

Second cancers among 104,760 survivors of cervical cancer: evaluation of long-term risk

BACKGROUND

Given the extended survival of patients diagnosed with cervical cancer, the large number of these women treated with radiotherapy, and the presence in this population of established cancer risk factors such as human papillomavirus (HPV) infection and cigarette smoking, it is important to clarify long-term trends in second cancer risk.

METHODS

Using data from 104,760 one-year survivors of cervical cancer reported to 13 population-based cancer registries in Denmark, Finland, Norway, Sweden, and the United States, we calculated standardized incidence ratios (SIRs) for second cancers overall and cancers at particular sites among women with cervical cancer, including cervical cancer patients who were treated or not treated with radiation, over more than 40 years of follow-up. Cox regression models were used to assess the time-varying association of radiotherapy with risk of second cancers and to assess the interaction of radiation treatment with age at diagnosis. All statistical tests were two-sided.

RESULTS

Among 104,760 one-year survivors of cervical cancer, the risk of all second cancers taken together was increased to a statistically significant extent (n = 12,496; SIR = 1.30; 95% confidence interval [CI] = 1.28 to 1.33). Compared with the general population, in both radiotherapy (N = 52,613) and no-radiotherapy groups (N = 27,382), risks for HPV-related cancers (of the pharynx, genital sites, and rectum/anus) and smoking-related cancers (of the pharynx, trachea/bronchus/lung, pancreas, and urinary bladder) were elevated to a statistically significant extent. Cervical cancer patients treated with radiotherapy, but not those who did not receive radiotherapy, were at increased risk for all second cancers and cancers at heavily irradiated sites (colon, rectum/anus, urinary bladder, ovary, and genital sites) beyond 40 years of follow-up compared with women in the general population. The association of radiotherapy with second cancer risk was modified by age at cervical cancer diagnosis for rectum/anus, genital sites, and urinary bladder, with higher hazard ratios for second cancer at younger ages of cervical cancer. After adjustment for competing mortality, the 40-year cumulative risk of any second cancer was higher among women diagnosed with cervical cancer before age 50 (22.2%; 95% CI = 21.5% to 22.8%) than among women diagnosed after age 50 (16.4%; 95% CI = 16.1% to 16.9%).

CONCLUSION

Cervical cancer patients treated with radiotherapy are at increased risk of second cancers at sites in close proximity to the cervix beyond 40 years of follow-up.

The assessment of postoperative pain by monitoring skin conductance: results of a prospective study

The number of fluctuations of skin conductance per second correlates with postoperative pain. The aim of this prospective study was to test the cut-off value for the number of fluctuations of skin conductance per second obtained from a previous study. Seventy-five patients were asked to quantify their level of pain on a numeric rating scale (0-10) in the recovery room. The number of fluctuations of skin conductance per second was recorded simultaneously. The number of fluctuations of skin conductance per second was different between patients with no (0.07), mild (0.16), moderate (0.28) and severe pain (0.33); p < 0.001. The tested cut-off value for the number of fluctuations of skin conductance per second (0.1) distinguished a numeric rating scale </= 3 from > 3 with 88.5% sensitivity and 67.7% specificity. The number of fluctuations of skin conductance per second may be a useful means of assessing postoperative pain.

Noncancer Causes of Death in Survivors of Testicular Cancer

BACKGROUND

Although modern treatments for testicular cancer are associated with increased survival, the long-term health effects of these treatments are unclear. We conducted a population-based study to quantify the long-term risks of mortality from noncancer causes among men with testicular cancer.

METHODS

We identified 38,907 one-year survivors of testicular cancer within 14 population-based cancer registries in North America and Europe (from 1943 through 2002). We used data from these registries to calculate standardized mortality ratios (SMRs) for noncancer deaths and to evaluate associations between histology, age at testicular cancer diagnosis, calendar year of diagnosis, and initial treatment and the risk of noncancer mortality. All statistical tests were two-sided.

RESULTS

A total of 2942 deaths from all noncancer causes were reported after a median follow-up of 10 years, exceeding the expected number of deaths from all noncancer causes in the general population by 6% (SMR = 1.06, 95% confidence interval [CI] = 1.02 to 1.10); the noncancer standardized mortality ratios did not differ statistically significantly between patients diagnosed before and after 1975, when cisplatin-based chemotherapy came into widespread use. Compared with the general population, testicular cancer survivors had higher mortality from infections (SMR = 1.28, 95% CI = 1.12 to 1.47) and from digestive diseases (SMR = 1.44, 95% CI = 1.26 to 1.64). Mortality from all circulatory diseases was statistically significantly elevated in men diagnosed with testicular cancer before age 35 years (1.23, 95% CI = 1.09 to 1.39) but not in men diagnosed at older ages (SMR = 0.94; 95% CI = 0.89 to 1.00). Men treated with chemotherapy (with or without radiotherapy) in 1975 or later had higher mortality from all noncancer causes (SMR = 1.34, 95% CI = 1.15 to 1.55), all circulatory diseases (SMR = 1.58, 95% CI = 1.25 to 2.01), all infections (SMR = 2.48, 95% CI = 1.70 to 3.50), and all respiratory diseases (SMR = 2.53, 95% CI = 1.26 to 4.53). Testicular cancer patients who were younger than 35 years at diagnosis and were treated with radiotherapy alone in 1975 or later had higher mortality from all circulatory diseases (SMR = 1.70, 95% CI = 1.21 to 2.31) compared with the general population.

CONCLUSION

Men who have survived for at least 1 year after being diagnosed with testicular cancer have a slightly higher risk of dying from noncancer causes, including infections, digestive diseases, and circulatory diseases, than the general population. Men treated with chemotherapy in 1975 or later may be at particularly high risk.

Long-term solid cancer risk among 5-year survivors of Hodgkin's lymphoma

PURPOSE

Hodgkin's lymphoma (HL) survivors are known to be at substantially increased risk of solid cancers (SC). However, no investigation has used multivariate modeling to estimate the relative risk (RR), excess absolute risk (EAR), and cumulative incidence for specific attained ages and ages at HL diagnosis.

PATIENTS AND METHODS

We identified 18,862 5-year HL survivors from 13 population-based cancer registries in North America and Europe. Poisson regression was used to evaluate the effects of age at diagnosis, attained age, latency, sex, treatment, and year of diagnosis on the RR and EAR of SC.

RESULTS

Among 1,490 identified SC, 850 were estimated to be in excess. For most cancer sites, both RR and EAR decreased with age at HL diagnosis and showed strong dependencies on attained age. For a patient diagnosed at age 30 years and survived to > or = 40 years, modeled risks were significantly elevated for cancers of the breast (RR = 6.1), other supradiaphragmatic sites (RR = 6.0), and infradiaphragmatic sites (RR = 3.7); the largest RR (20-fold) was observed for malignant mesothelioma. Thirty-year cumulative risks of SC for men and women diagnosed at 30 years were 18% and 26%, respectively, compared with 7% and 9%, respectively, in the general population. For young HL patients, risks of breast and colorectal cancers were elevated 10 to 25 years before the age when routine screening would be recommended in the general population.

CONCLUSION

Multivariable modeling demonstrates for the first time temporal changes in SC risk not evident in unadjusted analyses, and can facilitate the development of individualized risk assessment and the creation of screening strategies for early detection.

Risk of second non-hematological malignancies among 376,825 breast cancer survivors

Breast cancer survivors are at increased risk of treatment-related second cancers. This study is the first to examine risk 30 or more years after diagnosis and to present absolute risks of second cancer which accounts for competing mortality. We identified 23,158 second non-hematological malignancies excluding breast in a population-based cohort of 376,825 one-year survivors of breast cancer diagnosed from 1943 to 2002 and reported to four Scandinavian cancer registries. We calculated standardized incidence ratios (SIR) and utilized a competing-risk model to calculate absolute risk of developing second cancers. The overall SIR for second cancers was 1.15 (95% confidence interval [CI] = 1.14-1.17). The SIR for potentially radiotherapy-associated cancers 30 or more years after breast cancer diagnosis was 2.19 (95% CI = 1.87-2.55). However, the largest SIRs were observed for women aged <40 years followed for 1-9 years. At 20 years after breast cancer diagnosis, the absolute risk of developing a second cancer ranged from 0.6 to 10.3%, depending on stage and age; the difference in the absolute risk compared to the background population was greatest for women aged <40 years with localized disease, 2.3%. At 30 years post breast cancer diagnosis, this difference reached 3.2%. These risks were small compared to the corresponding risk of dying from breast cancer. Although the absolute risks were small, we found persistent risks of second non-hematological malignancies excluding breast 30 or more years after breast cancer diagnosis, particularly for women diagnosed at young ages with localized disease.

Leukemia following breast cancer: an international population-based study of 376,825 women

PURPOSE

To quantify long-term temporal trends in the excess absolute risk (EAR) of secondary leukemia among breast cancer (BC) survivors, using multivariate analyses to evaluate the effects of subtype, age at BC diagnosis, attained age, and calendar year.

PATIENTS AND METHODS

We identified 376,825 1-year survivors of BC within 4 nationwide, population-based cancer registries in Sweden, Denmark, Finland, and Norway (1943-2001). Estimates of EAR (per 100,000 person-years) were modeled using Poisson regression methods and cumulative risks calculated using a competing risk model.

RESULTS

A total of 687 non-chronic lymphocytic leukemias (EAR = 9.05; 95% confidence interval (CI) = 7.5-10.7) was reported. Significantly elevated risks were observed for the first time for chronic myeloid leukemia (CML) (EAR = 2.06; 95% CI = 1.3-2.9) and acute lymphoblastic leukemia (ALL) (EAR = 0.62; 95% CI = 0.2-1.1), in addition to acute myeloid leukemia (AML) (EAR = 5.00; 95% CI = 3.9-6.2). Excesses of CML, ALL, AML and all leukemias combined persisted over 25 years after BC diagnosis. For all leukemias, EAR decreased with increasing calendar year (P = 0.04) of BC diagnosis. Risk for all leukemia and AML by calendar year of BC diagnosis depended on age at diagnosis. For women diagnosed with BC after 1985, the 10-year cumulative risk of leukemia for those diagnosed before and after age 50 was small, 0.10% and 0.14%, respectively.

CONCLUSIONS

Although secondary leukemia is a rare event, BC survivors experience statistically significant excesses for at least 25 years after diagnosis, including CML and ALL. Decreasing leukemia risks in recent calendar years likely reflect changes in treatment.