Most sources say that Estrone (E1) is a high risk for cancer. It is also a hormone in high amount after menopause.
Which point were you saying it was contradicting? That paper is from a company, and probably not on pubmed. While many points in that paper may be correct, it is their choice of wording, calling it a waste product, instead of a metabolite, and it assuming that estriol is not good because it doesn't convert back into estradiol. Estriol is not a waste product, but one if its metabolites is a waste product. Pubmed Reviews have more information from different sources put together by importance, and interpret results.
Which point were you saying it was contradicting? That paper is from a company, and probably not on pubmed. While many points in that paper may be correct, it is their choice of wording, calling it a waste product, instead of a metabolite, and it assuming that estriol is not good because it doesn't convert back into estradiol. Estriol is not a waste product, but one if its metabolites is a waste product. Pubmed Reviews have more information from different sources put together by importance, and interpret results.