Day 017 - 25 Jul 94 - Page 20

     
     1        between obesity and the incidence of breast cancer?
              A.  Well, this has been suggested, but to some extent it
     2        is secondary evidence in the sense that we know that women
              who are obese who have breast cancer do have a poorer
     3        outlook; they are much more likely to develop recurrence
              and have a poorer survival if they are obese.  The theory
     4        behind this is that we know in adipose tissue oestrogen
              like compounds may be produced.  Breast cancer is a
     5        hormonally influenced cancer.  This is why the common time
              when it most frequently develops is around about the time
     6        of the menopause, when there is this change in the
              hormonal environment, you might say, of the body.
     7
              So, in obese people one is again theorising that perhaps,
     8        because of the production of oestrogens in fatty tissue,
              one is changing the hormonal environment of that
     9        particular patient's body, therefore making them much more
              liable to recurrence and a poorer survival following the
    10        diagnosis of breast cancer.
 
    Q.   I understand from what you said you  called secondary
              evidence that you, at any rate, are quite a long way from
    12        implicating obesity as a cause of breast cancer?
              A.  Obesity as such, yes.  It may be a factor that is
    13        involved, but I do not think we have the concrete evidence
              available to us yet to say that it is definitely an
    14        associated factor.
 
    15   Q.   Can we go back to Dr. Kinlen's paper of 1987, page
              586: "Introduction.  The growth in interest over the past
    16        decade in dietary causes of human cancer is evident from
              the work reviewed in this issue of Cancer Surveys.  In
    17        many ways this seems belated, for by what more obvious way
              than through our diet might the environment cause many of
    18        the pronounced worldwide variations in cancer incidence
              that are attributed to it?
    19
              There are many examples of dietary manipulation in the
    20        laboratory producing tumour formation; and, for example,
              for almost 50 years mammary tumours have been produced in
         rodents by increasing their intake of fat (Tannenbaum,
              1942)".  I am not going to refer to it, Dr. Arnott, but
    22        that is reference 10 to your report, is it not?
              A.  Yes.
    23
         Q.   "There is also evidence for an association in man between
    24        fat consumption and cancer, particularly with breast and
              large bowel cancers.  In fact, a prestigious group of
    25        scientists recently concluded that among dietary
              constituents the evidence for carcinogenicity is strongest 
    26        for fat (National Research Council, 1982)".  Are they 
              Americans, those people, or British? 
    27        A.  No, Americans.
 
    28   Q.   "This paper", that is to say, Dr. Kinlen's paper "reviews
              the relevant evidence with particular reference to breast
    29        cancer.  The subject is of unquestioned importance for, if
              certain evidence is reliable (see below), fat may be
    30        judged the most carcinogenic constituent of the Western
              diet, and perhaps also the most important single cause of