Blogger's Note: paid subscription required to view full paper, the 'burning' question in the abstract is what other 7 cancers ??
~~~~~~~~~~~~~~~~~~
Cancer of unknown primary (CUP): does cause of death and family history implicate hidden phenotypically changed primaries?
Abstract
Background: Cancer of
unknown primary (CUP) is diagnosed at the metastatic stage. We aimed to
identify hidden primary cancers in CUP
patients by comparison with cancers in family
members. We take use of the fact that the cause of death in CUP patients
is
often coded as the cancer in the organ of fatal
metastasis.
Patients and methods:
Forty-one thousand five hundred and twenty-three CUP patients were
identified in the Swedish Family-Cancer Database, and
relative risks (RRs) were calculated for cancer
in offspring when family members were diagnosed with CUP and died of the
cancer
diagnosed in offspring.
Results: The RR for
lung cancer in offspring was 1.85 when a family member was diagnosed
with CUP and died of lung cancer. Significant
familial associations were found for seven other
cancers. Many familial associations were also significant when
offspring
CUP patients died of the cancer diagnosed in
family members.
Conclusions: The cause
of death after CUP diagnosis frequently matched the cancer found in a
family member, suggesting that the CUP had
originated in that tissue. The metastasis had
probably undergone a phenotypic change, complicating pathological tissue
assignment.
These novel data suggest that some CUP cases are
phenotypically modified primary cancers rather than cancers of unknown
primaries.