On 2014 Dec 30, Kausik Datta commented:

To add to Hilda Bastian's informative comment, the press release mentions the misleading statement not only in the title, but also in the first paragraph - stating definitively: "The study, published Nov. 17 by Proceedings of the National Academy of Sciences, shows that triclosan causes liver fibrosis and cancer in laboratory mice through molecular mechanisms that are also relevant in humans." (Emphasis mine.)

This is, at best, irresponsible journalism (and at worst, a terrible disservice to people living with cancer). What seems particularly galling is the fact that this sacrifice of scientific accuracy at the altar of needless sensationalism in the press release was perpetrated by none other than the University (UCSD) at which the work was done. This brings to mind once again the age-old tussle in science communication, between science and journalism.

At the same time, the authors cannot deflect the blame completely, especially since the lead author, quoted in the Press Release, didn't seem to emphasize at all the dosage effect of Triclosan administration and exposure route - which is rather odd, given that the Triclosan was either fed to the mice or injected directly into their peritoneal cavity at a high enough amount, none of which would apply to humans.

I hope the authors pay heed to the most germane points raised by Hilda about the further inclusion of the data; I'd be most interested in the actual experimental outcomes.

On 2014 Nov 21, Hilda Bastian commented:

The title and abstract of this article focuses on the positive finding in tumor promotion, without emphasizing that the findings were negative on causation, in a way that is clearly accessible for non-specialist readers. This is of particular importance, as a university press release issued for this study was headed with this misleading statement: "The dirty side of soap: Triclosan, a common antimicrobial in personal hygiene products, causes liver fibrosis and cancer in mice." This encouraged unwarranted alarm in the community (which I discuss further in this blog post).

A 2010 inventory of animal and clinical studies of triclosan safety (Rodricks JV, 2010) found that oncogenicity studies to that point had not found cancer-related increases in any species, except for liver cancer in mice. Without pre-registration of studies on this question, we are unaware of what the outcomes have been for all oncogenicity studies on this substance, and thus whether there is publication bias.

Further areas of uncertainty relate to the experiments here. The article does not report sufficient data and methodological information to enable adequate assessment of the level of uncertainty associated with the experiments (see the NIH's Proposed Principles and Guidelines for Reporting Preclinical Research). It would be helpful if the authors took the opportunity to include key data here, specifically:

• how the sample size was determined;
• the inclusion/exclusion criteria;
• exact data on the experiments' results (including confidence intervals);
• whether or not allocation of mice to the groups was random, and if so, details of the method of randomization (including whether or not there was blinding);
• whether there was blinding in outcome assessment.

On 2014 Nov 21, Hilda Bastian commented:

The title and abstract of this article focuses on the positive finding in tumor promotion, without emphasizing that the findings were negative on causation, in a way that is clearly accessible for non-specialist readers. This is of particular importance, as a university press release issued for this study was headed with this misleading statement: "The dirty side of soap: Triclosan, a common antimicrobial in personal hygiene products, causes liver fibrosis and cancer in mice." This encouraged unwarranted alarm in the community (which I discuss further in this blog post).

A 2010 inventory of animal and clinical studies of triclosan safety (Rodricks JV, 2010) found that oncogenicity studies to that point had not found cancer-related increases in any species, except for liver cancer in mice. Without pre-registration of studies on this question, we are unaware of what the outcomes have been for all oncogenicity studies on this substance, and thus whether there is publication bias.

Further areas of uncertainty relate to the experiments here. The article does not report sufficient data and methodological information to enable adequate assessment of the level of uncertainty associated with the experiments (see the NIH's Proposed Principles and Guidelines for Reporting Preclinical Research). It would be helpful if the authors took the opportunity to include key data here, specifically:

• how the sample size was determined;
• the inclusion/exclusion criteria;
• exact data on the experiments' results (including confidence intervals);
• whether or not allocation of mice to the groups was random, and if so, details of the method of randomization (including whether or not there was blinding);
• whether there was blinding in outcome assessment.