Generational risks for cancers not related to tobacco, screening, or treatment in the United States

Environmental and Economic Strategies for Primary Prevention of Cancer in Early Life

This article summarizes the evidence for environmental toxic exposures contributing to cancers in early life, focusing on the most common cancer sites in this age group. It provides examples of widespread avoidable exposures to human carcinogens through air, water, and food and then describes recent examples of successful initiatives to reduce exposure to chemicals linked to these cancer sites, through government policy, industry initiatives, and consumer activism. State government initiatives to reduce toxic chemical exposures have made important gains; the Toxics Use Reduction Act of Massachusetts is now 25 years old and has been a major success story. There are a growing number of corporate initiatives to eliminate toxics, especially carcinogens, from the products they manufacture and sell. Another important opportunity for cancer prevention is provided by online databases that list chemicals, their toxicity, and lower-toxicity alternatives; these can be used by businesses, health care institutions, consumers, and workers to reduce exposures to chemicals of concern. The article concludes by inviting pediatricians and public health professionals to include elimination of carcinogen exposures in their work to promote primary prevention of cancer in early life.

Geographic trends of tobacco-related cancers in Cyprus

BACKGROUND

Causal relationships have been previously established between smoking and various cancers. In Cyprus, 39 % of men and 14 % of women reported daily smoking in 2008. The objective of this study was to compare the incidence of tobacco-related cancers to all other cancers by district and rural-urban classification to understand the impact of tobacco in Cyprus.

METHODS

Data on lung, urinary bladder, oral, pharyngeal, head/neck, and laryngeal cancers were obtained from the Cyprus Cancer Registry (1998-2008). There were 3,635 patients with tobacco-related cancers and 18,780 with non-tobacco cancers. Univariate analysis comparing tobacco-related cancers and all other cancers were conducted with regards to age at diagnosis, age groups, sex, smoking status, disease stage, and rural/urban status, with a p-value of 0.05 considered significant. Smoking prevalence, lung cancer, and bladder cancer rates of Cyprus were also compared to a number of other European countries.

RESULTS

Patients with tobacco-related cancers were older than those with non-tobacco cancers (mean age 67.2 ± 12.4 vs. 62.4 ± 17.1, p < 0.0001). Among those with tobacco-related cancers, 80.1 % were male compared to 45.4 % males with other cancer types. The proportion of ever smokers was higher among males compared to females in urban and rural districts. Sub-districts 41 (Age Adjusted Rate (AAR) 41.9, 95 % CI: 35.7-48.1), 60 (AAR 40.3, 95 % CI: 35.2-45.3), and 50 (AAR 36.3, 95 % CI: 33.8-38.7) had the highest rates of tobacco-related cancers. The overall tobacco-related cancer rate was the highest among males in urban districts (AAR 60.8, 95 % CI: 58.2-63.5). Among tobacco-related cancers, lung cancer had the highest overall AAR (17.9 per 100,000) while head and neck cancer had the lowest overall AAR (5.3 per 100,000). Additionally, even though Cypriot males aged 65-69 years old exhibited higher smoking prevalence than other European countries, the overall lung and bladder cancer rates were lower in Cyprus.

CONCLUSION

Despite the high proportion of smokers in Cyprus, cancer rates are low compared to other countries. Future in-depth measurements of relevant risk factors and smoking exposure can help understand this phenomenon and provide insights for cancer prevention.

An integrated inspection of the somatic mutations in a lung squamous cell carcinoma using next-generation sequencing

Squamous cell carcinoma (SCC) of the lung kills over 350,000 people annually worldwide, and is the main lung cancer histotype with no targeted treatments. High-coverage whole-genome sequencing of the other main subtypes, small-cell and adenocarcinoma, gave insights into carcinogenic mechanisms and disease etiology. The genomic complexity within the lung SCC subtype, as revealed by The Cancer Genome Atlas, means this subtype is likely to benefit from a more integrated approach in which the transcriptional consequences of somatic mutations are simultaneously inspected. Here we present such an approach: the integrated analysis of deep sequencing data from both the whole genome and whole transcriptome (coding and non-coding) of LUDLU-1, a SCC lung cell line. Our results show that LUDLU-1 lacks the mutational signature that has been previously associated with tobacco exposure in other lung cancer subtypes, and suggests that DNA-repair efficiency is adversely affected; LUDLU-1 contains somatic mutations in TP53 and BRCA2, allelic imbalance in the expression of two cancer-associated BRCA1 germline polymorphisms and reduced transcription of a potentially endogenous PARP2 inhibitor. Functional assays were performed and compared with a control lung cancer cell line. LUDLU-1 did not exhibit radiosensitisation or an increase in sensitivity to PARP inhibitors. However, LUDLU-1 did exhibit small but significant differences with respect to cisplatin sensitivity. Our research shows how integrated analyses of high-throughput data can generate hypotheses to be tested in the lab.

Lung cancer in never smokers--a review

An estimated 10-25% of lung cancers worldwide occur in never smokers, i.e. individuals having smoked less than 100 cigarettes in their lifetime. Lung cancer in never smokers (LCINS) is more frequent in women, although large geographic variations are found. Histologically, adenocarcinomas predominate. The mere existence of LCINS suggests that risk factors other than smoking must be present. Exposure to environmental tobacco smoke (particularly in women) and exposure to workplace carcinogens (particularly in men) are the two most important alternative risk factors. However, a history of either is absent in more than a third of LCINS. The large proportion of women in LCINS suggest a hormonal element that may interact with other identified factors such as hereditary risks, a history of respiratory infections or disease, exposure to air pollution, cooking and heating fumes, or exposure to ionising radiation. The study of genomic polymorphisms finds constitutive DNA variations across subjects according to their smoking status, particularly in genes coding for enzymes that participate in the metabolism of certain carcinogens, in those coding for DNA repair enzymes, or in genes associated with tobacco addiction, or inflammatory processes. The type of molecular mutation in p53 or KRAS varies with smoking status. EGFR mutations are more frequent in never smokers, as are EML4-ALK fusions. The mutually exclusive nature of certain mutations is a strong argument in favour of separate genetic paths to cancer for ever smokers and never smokers. In the present paper we review current clinical and molecular aspects of LCINS.

Clinical Dosimetric Study of Three Radiotherapy Techniques for Postoperative Breast Cancer: Helical Tomotherapy, IMRT, and 3D-CRT

This paper is to investigate the dosimetric characteristics of Helical Tomotherapy (HT), step-and-shoot intensity-modulated radiation therapy (SaS-IMRT) and three-dimensional conformal radiation therapy (3D-CRT) for the postoperative breast cancer as well as their dosimetric comparison of the normal tissues. CT images of 10 postoperative patients with early stage breast cancer were transferred into HT, SaS-IMRT and 3D-CRT planning systems respectively after the target region and normal tissues were outlined by the same physician to assure the contour consistency. Each prescribed dose for three different modalities of plans was given to a total of 50 Gy in 25 fractions. Doses and irradiated volumes in heart, lungs, as well as conformity index (CI) and homogeneity index (HI) were evaluated for detailed comparison. All three plans showed appropriate coverage for the prescribed target dose in the dosimetric comparison. The CI in HT and SaS-IMRT as well as 3D-CRT was 0.68 ± 0.12, 0.58 ± 0.08 and 0.40 ± 0.08, respectively. The HI were 1.10 ± 0.03, 1.14 ± 0.02 and 1.17 ± 0.04, which appeared intergroup significant differences (p < 0.05). V5, V10, as well as V20 of the heart were smallest in 3D-CRT than HT and SaS-IMRT. V5 of the ipsilateral lung was the smallest in 3D-CRT than HT and SaS-IMRT (p < 0.05); However, V20 and V30 were smaller in HT and SaS-IMRT than 3D-CRT (p < 0.05). V5 of the contralateral lung was the smallest in 3D-CRT than other groups, with V10~V30 were basically similar in numeric values with not obvious discrepancy. Comparing with SaS-IMRT and 3D-CRT, HT technique in treating breast cancer had the best conformity and homogeneity index as well as steepest dose gradient due to its highly modulated beamlets with rotational technique. The heart volume irradiated was the smallest in conventional 3D-CRT, with SaS-IMRT was the largest among the three techniques, as expected. The volume of the contralateral lung irradiated was the smallest in 3D-CRT than other groups. V5 of the ipsilateral lung was the smallest in 3D-CRT than other two groups. V10~V30 in HT and SaS-IMRT were similar and better than 3D-CRT dosimetrically. We conclude that HT technique had advantages over SaS-IMRT and 3D-CRT based on the dosimetric comparison in this study, especially in the high dose region of ipsilateral lung, target homogeneity and dose uniformity.