Pentachlorophenol is a human carcinogen, Group 1

In October 2016 18 scientists met at IARC for evaluation of pentachlorophenol (PCP) as a human carcinogen. The panel classified PCP as ‘carcinogenic to humans’ Group 1. PCP is a persistent organic pollutant under the Stockholm Convention. Chlorophenols, mostly PCP, have been used as wood preservatives. The use was banned in Sweden in 1978 with few exceptions. Wood impregnated with PCP may still entail a health hazard. In case-control studies we associated use of chlorophenols, as well as phenoxy herbicides, with increased risk for soft-tissue sarcoma (1979) and malignant lymphoma, both Hodgkin’s disease and non-Hodgkin lymphoma (1981). These results were the first studies in the world showing a carcinogenic potential of these agents, and further discussed in an article published in 1982.

Our results associated exposure to chlorophenols and the weed-killers phenoxy herbicides, with contaminating TCDD, with increased risk for soft-tissue sarcoma and malignant lymphoma. The results were soon questioned by industry and its allied experts including scientists with their own hidden agenda, even with funds from the Swedish Cancer Society aimed at preventing cancer, see

http://www.tandfonline.com/doi/full/10.1080/02841860701753697

and

https://www.ncbi.nlm.nih.gov/pubmed/17086516

The lesson is that it took 37 years from the first publication showing PCP as a human carcinogen to establish causation, years that were lost for cancer prevention.

New study confirms increased risk for glioma associated with use of mobile phones and cordless phones

We published recently a pooled analysis of our case-control studies on glioma and use of mobile phones and cordless phones. The study has been published in Pathophysiology after pre-review and can be accessed via Internet. The results confirm a statistically significant increased risk for glioma and the risk increases with time from first use of the wireless phone and number of hours for use over the years. The risk is highest on the same side of the brain as the phone has been used, especially in the area with the highest exposure to microwaves, the temporal lobe, which would be expected.

These studies strengthen the 2011 classification by IARC at WHO that the microwave exposure is a ‘Possible human carcinogen’, Group 2B. In fact using the Hill viewpoints on association and causation it should be classified as Group 1, the agent causes human cancer. We have explored that fact in more detail in a previous article. The present results confirm that classification.

Our results have gained interest in many countries after a press release by Reuters and have also been discussed in the Finnish Medical newspaper. However, these worrying results for human health have not been discussed at all in Sweden, so the layman is uniformed about how important it is to avoid such exposure.

Decreased survival in patients with glioblastoma multiforme associated with use of mobile and cordless phones

In a new study a decreased survival was found in glioblastoma patients with long-term use of mobile and cordless phones. The study is free to download here.

According to the study use of wireless phones in the >20 years latency group (time since first use) yielded an increased hazard ratio (HR) = 1.7, 95% confidence interval (CI) = 1.2–2.3 for glioma, a decreased survival. For astrocytoma grade IV (glioblastoma multiforme; n = 926) mobile phone use yielded HR = 2.0, 95% CI = 1.4–2.9 and cordless phone use HR = 3.4, 95% CI = 1.04–11 in the same latency category. Due to the relationship with survival the classification of IARC (possibly carcinogenic to humans, Group 2B) is strengthened and RF-EMF should be regarded as human carcinogen requiring urgent revision of current exposure guidelines. The findings are discussed in detail in the article.

Using the Hill viewpoints from 1965 for evaluating strengths of evidence of the risk for brain tumors associated with use of mobile and cordless phones

Recently we published an article on use of mobile and cordless phones and the risk of brain tumors. It has been published in Reviews on Environmental Health (DOI 10.1515/reveh-2013-0006).

A summary (abstract) is given in the following.

 

Background: Wireless phones, i.e., mobile phones and

cordless phones, emit radiofrequency electromagnetic

fields (RF-EMF) when used. An increased risk of brain

tumors is a major concern. The International Agency for

Research on Cancer (IARC) at the World Health Organization

(WHO) evaluated the carcinogenic effect to humans

from RF-EMF in May 2011. It was concluded that RF-EMF

is a group 2B, i.e., a “possible”, human carcinogen. Bradford

Hill gave a presidential address at the British Royal

Society of Medicine in 1965 on the association or causation

that provides a helpful framework for evaluation of

the brain tumor risk from RF-EMF.

Methods: All nine issues on causation according to Hill

were evaluated. Regarding wireless phones, only studies

with long-term use were included. In addition, laboratory

studies and data on the incidence of brain tumors were

considered.

Results: The criteria on strength, consistency, specificity,

temporality, and biologic gradient for evidence of

increased risk for glioma and acoustic neuroma were

fulfilled. Additional evidence came from plausibility and

analogy based on laboratory studies. Regarding coherence,

several studies show increasing incidence of brain

tumors, especially in the most exposed area. Support for

the experiment came from antioxidants that can alleviate

the generation of reactive oxygen species involved in

biologic effects, although a direct mechanism for brain

tumor carcinogenesis has not been shown. In addition,

the finding of no increased risk for brain tumors in subjects

using the mobile phone only in a car with an external

antenna is supportive evidence. Hill did not consider all

the needed nine viewpoints to be essential requirements.

Conclusion: Based on the Hill criteria, glioma and acoustic

neuroma should be considered to be caused by RF-EMF

emissions from wireless phones and regarded as carcinogenic

to humans, classifying it as group 1 according to the

IARC classification. Current guidelines for exposure need

to be urgently revised.

Use of wireless phones and the risk of meningioma

No consistent association between use of mobile phones and cordless phones and risk meningioma has been shown in previous studies by our research group in Sweden and the Interphone study at IARC (WHO).

We have now performed a new case-control study including patients with meningioma diagnosed between 2007-2009. Again this study did not show a consistent increased risk of meningioma for use of mobile and cordless phones. The latency time (time from first use of the phone until tumour diagnosis) was in this new study longer than previously, at most > 25 years.

Thus, in the same studies different risks have been found for different tumour types; increased risk for malignant brain tumours (mostly glioma) and acoustic neuroma but not for meningioma. These results clearly indicate that the results cannot be explained by systematic bias in the studies. The conclusion is that wireless phones cause malignant brain tumours and acoustic neuroma.

Increased risk for acoustic neuroma in a new Swedish study

A new Swedish published in International Journal of Oncology shows an increased risk for acoustic neuroma associated with use of wireless phones; both mobile phones and cordless desktop phones (DECT). The article is freely available on the Internet.

During two study periods, 1997-2003 and 2007-2009, cases with acoustic neuroma were interviewed regarding their total use of mobile phones and DECT. Also other agents were assessed. As reference entity population based controls were used. The questionnaire was answered by 316 cases (patients) and 3,530 controls.

The risk for acoustic neuroma increased with cumulative use in hours of wireless phones and latency (time from first use until diagnosis). This is illustrated in the figures below. Tumour volume increased with cumulative use and latency adding further relevance to the findings. These results confirm an increased risk for acoustic neuroma among users of both mobile phones and cordless phones.

Figure1_acoustic

 

Figure2_acoustic

New study confirms an increased risk for malignant brain tumours associated with use of wireless phones

Recently we published our new case-control study on use of mobile phones and cordless phones and the risk of malignant brain tumours, mostly glioma. The cases were diagnosed during 2007-2009 and population based persons were used as the reference entity. Exposures on a variety of agents were assessed by mailed questionnaires supplemented by telephone interviews. This was done without knowing if it was a case or a control that was interviewed.

For persons with more than 25 years latency period (time since first use until tumour diagnosis) a 3-fold increased risk was found. The risk increased further for tumours located in the most exposed area of the brain, the temporal lobe, to a 5-fold increased risk.

There was also a statistically significant trend for increasing risk with total number of hours for use. Further details can be found in the published study.