SUMMARY REPORTS OF EXCHANGE SCIENTISTS

(1) Suminori Kono
Fukudka University School of Medicine
Department of Public Health

Sponsor and Host Institution:
prof. Walter Willett
Harvard University School of Public Health
Dates of visit: September 3, 1989 - October 1, 1989

Summary of Activities:
The objectives of my visit were 1) to clarify the future direction in epidemiology of diet and colorectal cancer, 2) to learn how to develop a dietary method with high quality which is applicable in the study of diet and cancer, and 3) to appraise data of colorectal polyps from our on-going study.
Prof. Willett has comprehensive knowledge regarding colon cancer and diet, especially fat intake and dietary fiber. Through repeated discussion with Prof. Willett and his colleagues, it became evident that high fat intake seems to be causally related to colon cancer whereas epidemiologic evidence is very weak as to low fiber intake. It was also recognized that vegetables and fruits have a strong possibility of protecting against the occurrence of colon cancer. Further study should be pursued in this direction. But, because the intake of nutrients is correlated with total energy intake, it is most important to adjust for total energy intake in the relation between colon cancer and specific nutrients or foods. Thus a valid dietary assessment is a prerequisite for the epidemiologic study of diet and colon cancer.
Regarding how to develop a suitable dietary method, it was emphasized that preliminary and basic efforts must be exercised without being applauded. But there seems to be several essential points in this step; i.e., to choose at most 50 or 60 foods which can distinguish an individual’s intake of nutrients based on a fairly large-scale survey and to validate the method within a study population.
Our data on alcohol and colorectal adenoma were exposed to critical appraisal at the Nutritional Seminar of the research staff of Prof. Willett. In our data, specific alcoholic beverages (beer, sake and wine) were associated with an increased risk of colorectal adenoma. In view of the strong link between fat intake and colon cancer, an integrated hypothesis was proposed. Because alcohol is known to enhance bile production the relation with specific beverages may exist only among those with high fat intake. For further understanding the relation between alcohol and colorectal adenoma (and also cancer), inclusion of a valid dietary survey was strongly recommended in our on-going study, which is otherwise excellent.



(2) Rikuo Machinami
Department of Pathology, Faculty of Medicine
The University of Tokyo

Sponsor and Host Institution:
Dr. Krishnan K. Unni
Department of Surgical Pathology, Mayo Clinic
Date of Visit: January 13 to February 12, 1990

Summary of Activities:
I visited the Department of Surgical Pathology, Mayo Clinic, at St. Mary's Hospital in the laboratory of Professor K.K.Unni from January 15 to February 2, 1990. During my stay at the Mayo Clinic I talked about “morphometric and DNA flow cytometric analysis of chondrosarcoma” for one hour on January 17. Prof. Unni allowed me to see many interesting cases of bone tumors under the microscope and I could understand why so many new entities of bone tumors have been reported from this department. We asked Professor Beabout of the Radiology Department of the Mayo Clinic to examine X-rays and to make radiological diagnosis of bone tumors every day. Although the radiologist's opinion is very important in the diagnosis of bone tumors, we do not have such radiologists in Japan. I think we should have bone tumor radiologists in the near future. It was very impressive for me that all the surgical material was examined as frozen sections. This may be one bit of evidence that the Mayo Clinic is patient-oriented. All the organs, blocks and histology slides have been kept in one place from the beginning of this Clinic; this may suggest how the research in a patient-oriented hospital should be.
I stayed for two days on February 5-6 at the National Cancer Institute, in Dr. Curt Harris’ department. In this department, cancer research is going on by molecular biological techniques. With young scientists, I discussed their work. While I was staying in this department I visited Dr. Travis and Dr. Solomon at the Clinical Center, and also Dr. Kakefuda and Dr. Stewart to discuss various problems in the fields of pathology and cancer research.
I also visited Yale University’s New Haven Hospital, Surgical Pathology Department on February 8-9 and discussed various aspects of human tumors with Prof. Rosai.
I hope many Japanese pathologists can visit institutions in the U.S.A. through this exchange program in the future.