[PET examinations of recurrent rectal carcinoma, 2]

We have shown previously that the bodies of vertebrates are made of a somatic and a visceral component, separated by thin fascial sheets (Chirurg 66: 1230). We postulated that advanced visceral cancers are confined in their pattern of lymphatic spread to one or a few distinct metastatic pathways. In this they are fundamentally different from somatic cancers. To investigate this hypothesis in vivo, we evaluated positive lymph nodes (LNs) on PET scan series of 58 consecutive patients with rectum cancers (RC) compared to breast cancers (BC). We conclude that in RC, a visceral cancer spreads mostly along only one caudocranial pathway (regional, para-aortic, mediastinal, supraclavicular LNs) and never affects somatic LNs. In contrast, BC and urogenital carcinomas, as somatic cancers spread to regional somatic LNs, but do not affect visceral LNs.