Relative risk of second malignant neoplasms highest among young adult cancer patients - a population-based registry study in Finland.

BACKGROUND AND PURPOSE: The objective of this study was to explore the incidence of second malignant neoplasms (SMNs) among adult cancer patients in Finland diagnosed with their first primary cancer (FPC) in 1992-2021. MATERIAL AND METHODS: The study used data from the population-based Finnish Cancer Registry (FCR). Risk estimates were calculated using the standardised incidence ratio (SIR), the ratio of observed second cancers compared to the expected numbers assuming the same cancer incidence as the corresponding sex-age-calendar year -split of the general population. RESULTS: A total of 573,379 FPCs were diagnosed during 1992-2021. During the follow-up, 60,464 SMNs were diagnosed. Male cancer patients had neither a decreased nor an increased risk (SIR 1.00 [95% CI, 0.99-1.01]) and female patients had an 8% increased risk (SIR 1.08 [95% CI, 1.06-1.09]) of developing any SMN compared to a FPC in the general population. The highest SIR of any SMN was observed in patients aged 20-39 -years at FPC diagnosis, and the SIR decreased by increasing age at diagnosis. Patients with lymphoid and haematopoietic tissue neoplasms, cancers of the mouth and pharynx, endocrine glands, respiratory and intrathoracic organs, skin, and urinary organs had the highest SIRs, while patients with cancers of the male genital organs and the female breast had the lowest SIRs. INTERPRETATION: Elevated SIRs were observed in cancer patients diagnosed at an early age and for FPCs known to be in large part attributable to lifestyle factors, which highlights the importance of monitoring and encouraging lifestyle changes.

Familial aggregation of early-onset cancers in early-onset breast cancer families.

The risk of early-onset (EO) breast cancer is known to be increased in relatives of EO breast cancer patients, but less is known about the familial risk of other EO cancers. We assessed familial risks of EO cancers (aged ≤40 years) other than breast cancer in 54 753 relatives of 5562 women with EO breast cancer (probands) by using a population-based cohort from Finland. Standardized incidence ratios (SIRs) and 95% confidence intervals (CI) were estimated by using gender-, age- and period-specific cancer incidences of the general population as reference. The risk of any cancer excluding breast cancer in first-degree relatives was comparable to population cancer risk (SIR 0.99, 95% CI: 0.84-1.16). Siblings' children of women with EO breast cancer were at an elevated risk of EO testicular and ovarian cancer (SIR = 1.74, 95% CI: 1.07-2.69 and 2.69, 95% CI: 1.08-5.53, respectively). The risk of EO pancreatic cancer was elevated in siblings of the probands (7.61, 95% CI: 1.57-22.23) and an increased risk of any other cancer than breast cancer was observed in children of the probands (1.27, 95% CI: 1.03-1.55). In conclusion, relatives of women with EO breast cancer are at higher familial risk of certain discordant EO cancers, with the risk extending beyond first-degree relatives.

Familial aggregation of early-onset cancers.

This registry-linkage study evaluates familial aggregation of cancer among relatives of a population-based series of early-onset (≤40 years) cancer patients in Finland. A cohort of 376,762 relatives of early-onset cancer patients diagnosed between 1970 and 2012 in 40,538 families was identified. Familial aggregation of early-onset breast, colorectal, brain and other central nervous system (CNS) cancer and melanoma was explored by standardized incidence ratios (SIR), stratified by relatedness. Gender-, age- and period-specific population cancer incidences were used as reference. Cumulative risks for siblings and offspring of the proband up to age ≤40 years were also estimated. Almost all early-onset cancers were sporadic (98% or more). Among first-degree relatives, SIR was largest in colorectal cancer (14, 95% confidence interval 9.72-18), and lowest in melanoma (1.93, 1.05-3.23). Highest relative-specific SIRs were observed for siblings in families, where also parent had concordant cancer, 90 (43-165) for colorectal cancer and 29 (11-64) for CNS cancer. In spouses, all SIRs were at population level. Cumulative risk of colorectal cancer by age 41 was 0.98% in siblings and 0.10% in population, while in breast cancer the corresponding risks were 2.05% and 0.56%. In conclusion, early-onset cancers are mainly sporadic. Findings support high familial aggregation in early-onset colorectal and CNS cancers. Familial aggregation in multiplex families with CNS cancers was mainly attributed to neurofibromatosis and in colorectal cancer to FAP- and HNPCC-syndromes. The pattern of familial aggregation of early-onset breast cancer could be seen to support very early exposure to environmental factors and/or rare genetic factors.

Does farm environment protect against type 1 diabetes mellitus?

AIMS/HYPOTHESIS: Hygiene hypothesis has been shown valid in respect of allergies and asthma but has not been, however, sufficiently studied in relation to type 1 diabetes mellitus. This study investigates the effect of childhood farm environment on the prevalence of type 1 diabetes mellitus in Finnish children and young adults. METHODS: Data come from a questionnaire study carried out in 2007 (N = 5805). Prevalence of type 1 diabetes mellitus was analysed according to the type of the rural exposure below the age of 18 years. Associations were estimated and tested using Bayesian methods. RESULTS: Consistent suggestive evidence of the inverse association of childhood's farm environment with the occurrence of type 1 diabetes mellitus was shown, even though conclusive results were not reached. CONCLUSION/INTERPRETATION: Exposure to a broad variety of non-pathogenic environmental microorganisms during childhood might have a protective effect on type 1 diabetes mellitus. Results clearly suggest that further research is well grounded with larger samples.