We collected multiple primary cancers of different organs or tissues. We excluded the multicentric origin of cancer in the same tissue of a single organ or bilaterally paired organs, or in common contiguous tissue shared by different organs. (except the cases which are diffe. rent in pathology or in cell differentiation). Twenty one cases of multiple primary cancer, histologically proven and treated from January, 1978 to December 1982 at the Department of Surgery, Seoul National University Hospital, have been clinically studied.
The results were as follows:
1) The incidence of multiple primary cancer is 0.74% for 5 years(1978?1982).
2) Female outnumbered male by ratio of 1.1:1 and age incidence was most prevalent in the 6th and 7th decades comprising 85.7% of all cases.
3) The incidence of multiple primary cancer increased annually and markedly increased in i982.
4) The ratio between synchronous and metachronous(interval more than 6 month) is 1:1.
The time interval between first and second cancer is average 5.7 years in metachronous cases. The 6 cases of 11 metachronous cases were treated with radiation or immunochernotherapy after first operation.
In metachronous cases, the site of second tumor is stomach(6), colorectal(4), cervix(l) in order of frequency.
5) Family history of all cases were unreliable.
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