Frøydis Langmark

Data quality at the Cancer Registry of Norway: An overview of comparability, completeness, validity and timeliness

AIM To provide a comprehensive evaluation of the quality of the data collected on both solid and non-solid tumours at the Cancer Registry of Norway (CRN). METHODS Established quantitative and semi-quantitative methods were used to assess comparability, completeness, accuracy and timeliness of data for the period 1953-2005, with special attention to the registration period 2001-2005. RESULTS The CRN coding and classification system by and large follows international standards, with some further subdivisions of morphology groupings performed in-house. The overall completeness was estimated at 98.8% for the registration period 2001-2005. There remains a variable degree of under-reporting particularly for haematological malignancies (C90-95) and tumours of the central nervous system (C70-72). For the same period, 93.8% of the cases were morphologically verified (site-specific range: 60.0-99.8%). The under-reporting in 2005 due to timely publication is estimated at 2.2% overall, based on the number of cases received at the registry during the following year. CONCLUSION This review suggests the routines in place at the CRN yields comparable data that can be considered reasonably accurate, close-to-complete and timely, thereby justifying our policy of the reporting of annual incidence one year after the year of diagnosis.

Leukemia Following Hodgkin's Disease

To investigate the effect of different treatments for Hodgkins disease on the risk of leukemia, we used an international collaborative group of cancer registries and hospitals to perform a case-control study of 163 cases of leukemia following treatment for Hodgkins disease. For each case patient with leukemia, three matched controls were chosen who had been treated for Hodgkins disease but in whom leukemia did not develop. The use of chemotherapy alone to treat Hodgkins disease was associated with a relative risk of leukemia of 9.0 (95 percent confidence interval, 4.1 to 20) as compared with the use of radiotherapy alone. Patients treated with both had a relative risk of 7.7 (95 percent confidence interval, 3.9 to 15). After treatment with more than six cycles of combinations including procarbazine and mechlorethamine, the risk of leukemia was 14-fold higher than after radiotherapy alone. The use of radiotherapy in combination with chemotherapy did not increase the risk of leukemia above that produced by the use of chemotherapy alone, but there was a dose-related increase in the risk of leukemia in patients who received radiotherapy alone. The peak in the risk of leukemia came about five years after chemotherapy began, and a large excess persisted for at least eight years after it ended. After adjusting for drug regimen, we found that patients who had undergone splenectomy had at least double the risk of leukemia of patients who had not, and an advanced stage of Hodgkins disease carried a somewhat higher risk of leukemia than Stage I disease. We conclude that chemotherapy for Hodgkins disease greatly increases the risk of leukemia and that this increased risk appears to be dose-related and unaffected by concomitant radiotherapy. In addition, the risk is greater for patients with more advanced stages of Hodgkins disease and for those who undergo splenectomy.

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

PURPOSE Hodgkins 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 subsequent malignant neoplasms among 1,641 Hodgkin's disease patients diagnosed in childhood and adolescence: a population-based cohort study in the five Nordic countries. Association of the Nordic Cancer Registries and the Nordic Society of Pediatric Hematology and Oncology.

PURPOSE To assess the risk of subsequent malignant neoplasms among Hodgkins disease patients diagnosed before 20 years of age in the five Nordic countries (Denmark, Finland, Iceland, Norway, and Sweden). PATIENTS AND METHODS There were 1,641 Hodgkins disease patients identified through the national cancer registries since the 1940s or 1950s. The patients were monitored for 17,000 person-years until the end of 1991. Expected figures were derived from the age-specific incidence rates in each country and standardized incidence ratios (SIR) were calculated. RESULTS A total of 62 subsequent neoplasms were diagnosed (SIR, 7.7; 95% confidence interval [CI], 5.9 to 9.9). The overall cumulative risk of subsequent neoplasms was 1.9% at the 10-year follow-up point, 6.9% at 20 years, and 18% at 30 years. There were 26 subsequent neoplasms among males (SIR, 6.5; 95% CI, 4.3 to 9.6) and 36 among females (SIR, 8.9; 95% CI, 6.2 to 12), of which 16 were breast cancers (SIR, 17; 95% CI, 9.9 to 28). High risks were seen for thyroid cancer (SIR, 33; 95% CI, 15 to 62), for secondary leukemia (SIR, 17; 95% CI, 6.9 to 35), and for non-Hodgkins lymphoma (SIR, 15; 95% CI, 4.9 to 35). The relative risk increased from 3.3 (95% CI, 1.2 to 7.1) for Hodgkins disease patients diagnosed in the 1940s and 1950s to 15 (95% CI, 7.4 to 27) in the 1980s. The highest risk of secondary leukemia (SIR, 68; 95% CI, 18 to 174) was seen among those diagnosed with Hodgkins disease in the 1980s. CONCLUSION Patients who survive Hodgkins disease at a young age are at very high relative risk of subsequent malignant neoplasms throughout their lives. In particular, the high relative risk of breast cancer following Hodgkins disease in the teenage years calls for enhanced activity for early diagnosis.

SECOND MALIGNANT NEOPLASMS AFTER CANCER IN CHILDHOOD AND ADOLESCENCE: A POPULATION-BASED CASE-CONTROL STUDY IN THE 5 NORDIC COUNTRIES

Our purpose was to assess the risk of developing a second malignant neoplasm (SMN) after cancer in childhood and adolescence associated with different treatment modalities. Our investigation was performed as a nested case‐control study within a Nordic cohort of 25,120 patients younger than 20 years old at first malignant neoplasm (FMN) diagnosed in 1960 through 1987. SMNs were diagnosed in 1960 through 1991. For each case of SMN, 3 controls were sampled, matched by sex, age, calendar year of diagnosis and length of follow‐up. For the final analysis, there were 234 cases and 678 controls. Relative risks (RRs) of various exposures were estimated by means of conditional logistic regression, with non‐exposed as the reference. The RR of developing SMN in the radiated volume was 4.3 (95% confidence interval 3.0–6.2). The risk was highest in children diagnosed before the age of 5 years; it increased with the dose of radiation and with increasing follow‐up time after FMN. Chemotherapy alone was not associated with an increased RR, but it significantly potentiated the effect of radiotherapy. RRs were unchanged between the periods 1960–1973 and 1974–1987, and since the use of chemotherapy increased in the latter period, the number of SMNs may increase. Hereditary factors were important for the occurrence of SMN independently of therapy. We conclude that radiation was the most important treatment‐related risk factor for the development of SMN. Chemotherapy appeared to play only an accessory role during the study period, potentiating the carcinogenic effect of radiotherapy. Int. J. Cancer 88:672–678, 2000.

Risk of cancer among offspring of childhood-cancer survivors

BACKGROUND Increasing numbers of children with cancer survive and reach reproductive age. However, the risk of cancer (other than retinoblastoma) in the offspring of survivors of childhood and adolescent cancer is uncertain. METHODS Using data from national cancer and birth registries, we assessed the risk of cancer among 5847 offspring of 14,652 survivors of cancer in childhood or adolescence diagnosed since the 1940s and 1950s in Denmark, Finland, Iceland, Norway, and Sweden. The offspring were followed up for a diagnosis of cancer for 86,780 person-years, and standardized incidence ratios were calculated. RESULTS Among the 5847 offspring, 44 malignant neoplasms were diagnosed (standardized incidence ratio, 2.6; 95 percent confidence interval, 1.9 to 3.5). There were 17 retinoblastomas, yielding a standardized incidence ratio of 37. There were 27 neoplasms other than retinoblastoma (standardized incidence ratio, 1.6; 95 percent confidence interval, 1.1 to 2.4). The second most common primary site of cancer among the offspring was the brain and nervous system, in which eight tumors were observed (standardized incidence ratio, 2.0; 95 percent confidence interval, 0.9 to 3.9.) There were between zero and four apparently sporadic cases of cancer in other primary sites among the offspring. Excluding 4 likely cases of hereditary cancer and 2 subsequent cancers among the offspring with hereditary retinoblastoma, there were 22 sporadic cancers, for a standardized incidence ratio of 1.3 (95 percent confidence interval, 0.8 to 2.0). CONCLUSIONS There is no evidence of a significantly increased risk of nonhereditary cancer among the offspring of survivors of cancer in childhood.

Lifelong Cancer Incidence in 47 697 Patients Treated for Childhood Cancer in the Nordic Countries

BACKGROUND The pattern of cancer in long-term survivors from childhood cancer has not been investigated comprehensively. METHODS We obtained a cohort of 47,697 children and adolescents aged 0-19 years with cancer as defined by the country-wide cancer registries of Denmark, Finland, Iceland, Norway, and Sweden during 1943-2005. Cohort members were followed through age 79 years for subsequent primary cancers notified to the registries, and the age-specific risk pattern of the survivors was compared with that of the national populations using country and sex standardized incidence ratios (SIRs). We used a multiplicative Poisson regression model to estimate relative risk of cancer for attained age, with adjustment for calendar period and age at diagnosis of primary cancer. We also calculated excess absolute risk (EAR) attributable to status as childhood cancer survivor and determined the cumulative incidence of second primary cancer as a function of attained age for three subcohorts defined by period of treatment for childhood cancer. RESULTS A total of 1180 asynchronous second primary cancers were observed in 1088 persons, yielding an overall SIR of 3.3 (95% confidence interval = 3.1 to 3.5). The relative risk was statistically significantly increased in all age groups, even for cohort members approaching 70 years of age. The EAR for second primary cancer among survivors increased gradually from one additional case per 1000 person-years of observation in early life to six additional cases per 1000 person-years in the age group 60-69 years. For children treated in the prechemotherapy era (1943-1959), the cumulative risk for a second primary cancer reached 18%, 34%, and 48% at ages 60, 70, and 80 years, respectively. The age-specific incidence rates were highest for cohort members treated in the era of intensive, multiple-agent chemotherapy (1975-2005). CONCLUSION Survivors of childhood cancer have a persistent excess risk for a second primary cancer throughout their lives, accompanied by continuous changes in the risk of cancers at specific sites.

Neoplasms of the central nervous system in Norway

A population‐based study of 8480 patients ‐ 4508 (53%) males and 3972 females ‐ with primary intracranial neoplasms reported to the Norwegian Cancer Registry during the period 1955‐84, is presented. 81% of the cases were histologically verified. The peak age‐specific incidence rate in the total series occurred in the age‐group 55–64 years. Gliomas constituted the largest histological group with an age‐adjusted incidence rate of 5.0 cases per 100,000 population per year for males and 3.5 for females. Case ascertainment of primary intracranial neoplasms is reduced above the age of 60 in Norway, mostly due to a low autopsy rate. The major impact of the introduction of computer tomography (CT) in the case ascertainment of intracranial neoplasms has been a raised incidence, in patients over the age of 60, of neoplasms which are not histologically verified.

Cancer in siblings of children with cancer in the Nordic countries: a population-based cohort study

BACKGROUND In some rare inherited disorders such as Li-Fraumeni syndrome, relatives of children with cancer are at increased risk of cancer. We aimed to assess relations between childhood cancer and sibling risk, and evaluate the influence of recessive conditions in cancer causation. METHODS We did a population-based cohort study in the Nordic countries of 42277 siblings of 25605 children with cancer. Children with cancer were identified from records in the five Nordic cancer registries, and their siblings from nationwide population registries. Cancers in siblings were documented through record linkage with cancer registries and compared with national incidence rates. We also assessed cancer incidence in parents to identify familial cancer syndromes. FINDINGS 284.2 cancers were expected in siblings, whereas 353 were diagnosed (standardised incidence ratio 1.24 95% CI 1.12-1.38). Risk ratios for siblings were highest in the first decade of life (2.59, 1.89-3.46). We excluded 56 families with genetic syndromes linked to cancer, which reduced this ratio from 1.7 to 1.0 (0.7-1.3) for siblings younger than 20 years, and from 1.3 to 1.0 (0.8-1.3) for those aged 20-29 years. We found no new patterns of familial cancer that indicated inherited susceptibility, or evidence that recessive conditions might contribute to cancers not explained by syndromes. 40% of cancers in siblings that occurred before age 20 years could be attributed to known genetic factors, whereas 60% remained unexplained. INTERPRETATION Apart from rare cancer syndromes, paediatric cancer is not an indicator of increased cancer risk in siblings.

Stomach Cancer Risk After Treatment for Hodgkin Lymphoma

PURPOSE Treatment-related stomach cancer is an important cause of morbidity and mortality among the growing number of Hodgkin lymphoma (HL) survivors, but risks associated with specific HL treatments are unclear. PATIENTS AND METHODS We conducted an international case-control study of stomach cancer nested in a cohort of 19,882 HL survivors diagnosed from 1953 to 2003, including 89 cases and 190 matched controls. For each patient, we quantified cumulative doses of specific alkylating agents (AAs) and reconstructed radiation dose to the stomach tumor location. RESULTS Stomach cancer risk increased with increasing radiation dose to the stomach (Ptrend < .001) and with increasing number of AA-containing chemotherapy cycles (Ptrend = .02). Patients who received both radiation to the stomach ≥ 25 Gy and high-dose procarbazine (≥ 5,600 mg/m(2)) had strikingly elevated stomach cancer risk (25 cases, two controls; odds ratio [OR], 77.5; 95% CI, 14.7 to 1452) compared with those who received radiation < 25 Gy and procarbazine < 5,600 mg/m(2) (Pinteraction < .001). Risk was also elevated (OR, 2.8; 95% CI, 1.3 to 6.4) among patients who received radiation to the stomach ≥ 25 Gy but procarbazine < 5,600 mg/m(2); however, no procarbazine-related risk was evident with radiation < 25 Gy. Treatment with dacarbazine also increased stomach cancer risk (12 cases, nine controls; OR, 8.8; 95% CI, 2.1 to 46.6), after adjustment for radiation and procarbazine doses. CONCLUSION Patients with HL who received subdiaphragmatic radiotherapy had dose-dependent increased risk of stomach cancer, with marked risks for patients who also received chemotherapy containing high-dose procarbazine. For current patients, risks and benefits of exposure to both procarbazine and subdiaphragmatic radiotherapy should be weighed carefully. For patients treated previously, GI symptoms should be evaluated promptly.