Index: comment pages

• PVC linked to cancer?
• Chlorine in tap water and miscarriages
• Toxic secrets: the Houston chronicles 
• Dioxins, chickens and eggs in Belgium
• Greenpeace uses PVC!
• Dioxins in fodder (2004)
• Dioxins in fodder (2006)

FAIRY-TALE

According to recent (Swedish) research, phthalates are also under suspect as a possible cause of testicular cancer.

Greenpeace Netherlands called on the Dutch environment minister Margaretha de Boer to end the production and use of PVC, and to respond to the Swedish study in a parliamentary debate on PVC

FACTS AND FIGURES

The Swedish cancer study

Parts of this page

The Örebro study
Review by toxicologists

Conclusion

PVC and testicular cancer

Besides the possible introduction of just chance by such a low number of "PVC-exposed"-cases against "PVC-exposed"-non-cases, one of the "PVC-exposed"-cases worked only three days in a PVC-factory...

The researchers conclusion was:

"In conclusion, in our case-control study of testicular cancer, a somewhat surprisingly high risk was observed for PVC plastics. The shortcomings of retrospective assesment of exposure by a self-administered questionnaire are obvious, and spurious association between PVC exposure and seminima cannot be ruled out. Therefore, our results must be regarded as hypothesis generating and they warrant further studies."

The researchers thaught that phthalates, used as plasticiser in PVC, might be the cause, because some of these have (very weak) oestrogenic effects in some in-vitro tests. But no phthalates have shown oestrogenic effects in living animals (see our Chlorine and hormonal changes pages), even if administered continuously over two generations [25] [26]. And as far as we know, no testicular cancer was seen in animals, even when doses equivalent to 500 g/day (!) for an adult were given...

Letters of Greenpeace and other environmental groups have triggered questions of several MP's during the discussion on the use of PVC in The Netherlands.
The reaction of the Dutch environment minister Margaretha de Boer to these questions was quite clear:
The recent Swedish study on testicular cancer is only the generation of a new hypothesis and needs further investigation. This study will not influence the policy of the government now.

Review of the study by toxicologists

1. The questionnaire was a self-administered questionnaire but the questions are not presented and the context in which it was distributed is not described, neither the validation process. Increased odd ratios are presented for a so-called PVC exposure but no element are given about other possible increased odd-ratios among the other possibly subjective responses to the questionnaire. While the numbers cannot be disputed as such, they need to be put in much more accurate perspective with any other possible correlation with the other responses and possible bias. This was not done since "results of other occupations and exposures will be published elsewhere". Indeed, PVC exposure is a rather ill-defined and subjective criteria when it has to be causatively correlated with a very specific outcome such as a testicular cancer.
2. In the introduction of the paper it is stated that the frequency of testicular cancer is more frequently increasing in young men. By contrast, the age of men in the study when their testicular is diagnosed is comprised between 36 and 62 years old and with a so-called latency period of 22 years! It is easy to observe among the cases presented that there is indeed a clear trend to develop a testicular cancer at a younger age but which is related NEITHER to the intensity of the so-called "PVC exposure", neither correlated to any alleged (unfounded terminology and mis-leading) "latency period". On the contrary, with the major improvement of working conditions in the industry in general, and in the PVC industry in particular, the level of exposure to "PVC" has continuously decreased over the last 25 years. Also, there is a strange skewed distribution in the form of testicular cancer in the so-called PVC exposure group described in the article. Actually the only non-seminoma in the table is presented at the age of 36 after less than 3 days of working in a PVC factory 10 years earlier.


Furthermore the IARC report on "Mortality and cancer incidence results of the European multi-centric cohort study of workers" in a study population of 12706 employees (222.746 persons years at risk) found only 3 cases of death related to testicular cancer. In the group of 2643 workers, from 4 plants in Norway and Sweden (3 VCM/PVC production plants and one processing plant) only one case was observed while 2.21 cases were expected.
 

The "PVC" cancer cases
year of birth	age at diagnosis	period between first "PVC exposure" and diagnosis	cumulated exposure
1930	62	35	6
1931	58	22	4
1939	50	12	12
1945	46	26	8
1947	44	22	5
1953	26	11	0, 0 1 (= 3 days !)
1956	36	15	2

3. Although the paper is said hypothetical, none of the hypothesis proposed holds on a elementary analysis:
• hypothetical link with chlorine with no argument : chlorine is not a carcinogen, can we suspect an emotional link ?
• hypothetical link with phthalates and a supposed estrogeno-mimetic effect: the basis is a publication (Jobling, Sumpter et al., 1995) which is now outdated by more recent work, including data from the same laboratory of Sumpter, demonstrating the lack of estrogenic potential of DEHP and its metabolites but also of other major phthalates used in PVC, this both in vitro and in vivo;
• hypothetical link with carcinogenicity of DEHP and cancer: DEHP is not considered as a carcinogen for humans on basis of metabolism studies in primates; furthermore, DEHP tumorigenicity of rodents is specifically associated to peroxisome proliferation in the liver, DEHP was never suspected to induce cancer of the testicles;
• hypothetical link with stillbirths : the relation with testicular cancer is simplistic and not scientifically founded and, again, purely "emotional"; furthermore the hypothesis of 1987 relating stillbirths and PVC was never confirmed by any further correlative data.

CONCLUSION

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Created: 15 February, 1998.
Last update: 6 February, 2006.

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