Day 017 - 25 Jul 94 - Page 47


     
     1        starting with the first complete paragraph: "Faecal bile
              acids levels have been measured in high and low risk
     2        populations".
 
     3   MR. MORRIS:  Where are we?
 
     4   MR. RAMPTON:  Page 599.  "This epidemiological approach has
              been utilized by several groups and strongly supports the
     5        role of bile acids in large bowel carcinogenesis.  It has
              been suggested that increased consumption of meat and
     6        hence animal fat would account for the high-risk
              populations.  There is a close relationship between per
     7        capita meat intake and colorectal cancer incidence in
              various populations.   Seventh Day Adventists who consume
     8        little or no meat show a relatively low rate of colorectal
              cancer as compared to their fellow Americans.  However, a
     9        survey of dietary variations within Seventh Day Adventists
              showed no relationship between  meat consumption and large
    10        bowel cancer.  New Zealand Maoris enjoy a high intake of
              fat and protein, yet the incidence of colorectal cancer is
    11        low in this  group.
 
    12        It is relevant also that dietary manipulation has failed
              to influence the bacterial flora of the large intestine.
    13        Case control studies (in which each patient with
              colorectal cancer is matched to a 'normal' control) have
    14        usually failed to support a link between either meat
              intake or faecal bile  acid levels and colorectal cancer.
    15        It is important that patients with colorectal cancer are
              carefully selected for such studies.  Patients with cancer
    16        may have modified their diet and the presence of liver
              metastases" -- those are substances, are they?
    17        A.  No.  Liver metastases are where the cancer has spread
              to the liver and formed secondary growth within the liver
    18        itself.  So a metastases is a secondary growth which is in
              fact one of the characteristics of cancer as I described
    19        this morning.
 
    20   Q.   I will finish the sentence and then I will ask you about
              it. "The presence of liver metasates could influence bile
    21        acid metabolism." Is that so far as your expertise is
              concerned a correct statement of affairs?
    22        A.  Well, it could do.  In reality we are able to live
              with quite a lot of our liver involved by cancer and still
    23        lead, you know -- the ostensible test one can perform on
              patients show little abnormality.  But the point he is
    24        making is that when you are looking at patients with
              cancer there are other factors which may come into play,
    25        such as have they modified their diet themselves.  We have
              talked about this morning with regard to breast cancer; 
    26        they recall of previous diet may be influenced by the fact 
              that they know now they have cancer.  The actual natural 
    27        history and behaviour of the tumour itself may in some way
              influence metabolism, such as if you get deposits within
    28        the liver, the liver is undoubtedly affected and it may,
              therefore, influence the metabolism of the bile acids.
    29
         Q.   He goes on, Dr. Morson:  "It has been argued that the
    30        failure of case control studies to support dietary and/or
              faecal bile acid hypothesis may reflect the confounding

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