Intraperitoneal cancer primary site of origin is a diagnosis
of exclusion reached by a process of elimination, which is the method
used to identify the intraperitoneal cancer source of the highest
probability. The method of elimination is iterative. The possible
primary site of origin of intraperitoneal cancer in every patient
considered for enrollment in this meta-analysis was identified. Every
case enrolled from published cohorts into the present meta-analysis
had established resections of several primary sites (breast, ovary,
fallopian tube, and uterus), thus eliminating these as primary site
possibilities. This left only 4 intra-abdominal sites of intraperitoneal
cancer: appendix, colon, GI tract, or pancreas. The latter GI sources
(colon, GI tract, and pancreas) cannot be accepted as probable primary
sites with no primary organ mass and no symptoms, which leads to greater
than 99.99% diagnosis before classification as intraperitoneal cancer.
Any BRCA1/2 mutation carrier reported to
have colon, gastric, or pancreatic cancer was excluded from the analysis.