Surgery is only useful when the cancer is localized. Indeed, when the cancer is at an advanced stage with distant metastases, it means that the tumor cells are circulating in the blood, so it is not always essential to perform a carcinological surgery. This is why a so-called extension workup of the disease must be performed before a carcinological surgery is validated. Curative surgery consists in the total removal of the tumor by taking safety margins that do not contain any tumor visible to the naked eye. If the margins are healthy, the resection is said to be R0. However, it may happen that these margins are microscopically contaminated by cancer after anatomopathological examination: this is called R1 resection. It may then be proposed that these margins be resected until they are in healthy tissue. Finally, it is possible to fail to remove the tumor in its entirety, a macroscopic residue is therefore left in place: R2 resection. The objective of preoperative imaging is to avoid this situation, which is a failure of carcinological surgery. In addition to tumor removal, it is often necessary to analyze the lymph nodes that drain the tumor site. Indeed, these nodes are the first ‘communicators’ of the existence tumor cells prior to their dissemination to other organs.
Two removal techniques are possible :
Lymph node dissection which consists of removing the entire chain of lymph nodes and subsequently analyzing the removed tissue. It is typical to include complementary treatment with the surgical procedure if the lymph nodes have been compromised. (e.g., radiotherapy and / or chemotherapy.).
A sentinel node procedurewhich is a less invasive technique. The surgeon first injects a marker to identify the first node(s) that relay between the tumor and the patient’s general circulatory system. These nodes are removed and analyzed on site by the pathologist as an extemporaneous examination. If the lymph nodes are compromised, a complete dissection is performed. Otherwise, the rest of the ganglion chain is left in place.