Retrograde lymphatic spread: a likely route for metastatic ovarian cancers of gastrointestinal origin.

In order to outline the pathways of gastrointestinal malignancies metastasizing to the ovaries, we reviewed 103 cases of metastatic ovarian tumors, and also performed para-aortic lymph node sampling on 11 patients at operation for metastatic ovarian tumors. Of the 103 patients, 74% (26/35) with gastric cancer and 67% (45/67) with colorectal cancer had lymph node metastasis at or before the diagnosis of ovarian tumor. Intraperitoneal metastases presented in 49 and 42% of patients with gastric and with colorectal cancers, respectively. Twenty-three percent of gastric cancer patients and 25% of colorectal cancer patients presented with both lymph node and intraperitoneal metastases. The ovary was the first or among the early metastatic organs diagnosed in 51 of the 53 patients with metachronous ovarian metastases. Only 4 patients with colorectal cancer and none with gastric cancer showed parenchymal organ metastases. These 4 patients also showed intraperitoneal lesions, and 3 of these 4 patients had node metastasis. Among the 11 patients who underwent prospective para-aortic lymph node sampling during operation for the ovarian tumors, only 1 had enlarged para-aortic nodes depicted by computed tomography, 2 had grossly enlarged (>/=1.5 cm) para-aortic lymph nodes noted at surgery, and 6 of the 7 patients with gastric cancer and all 3 with colorectal cancer had metastatic nodes histologically. Among the 58 nodes taken from these patients, 67% showed metastatic foci. We concluded that lymph node metastasis is frequently seen in patients with metastatic ovarian tumors of gastrointestinal origin, and hypothesized that retrograde lymphatic spread is a likely route for the metastases.