10. Conclusion

dissection, we would have missed 8 out of 40 patients who did have metastases. Even with the use of only histopathological examination of the removed lymph nodes, we discovered 10 patients with metastases of the regional lymph nodes. With the use of classical method, the occult metastases were therefore discovered in 25% of the patients. This is an expected proportion of patients with the occult metastases [24–26]. To these patients, we have to add the patients in whom we have found the metastases with the serial cuts of the sentinel lymph nodes. There were eight of these patients. We see that the number of patients with occult metastases was close to 50%. With the use of classical histopathological examination, we would have discovered only around a half of the patients with the occult metastases. We cannot afford to examine all of the removed lymph nodes by serial cuts and immunohistochemical staining, due to the lack of personnel and funding. In selective dissection of the neck, we remove on average 13–15 lymph nodes, which would amount to more than 200 slices needing pathologist examination. Still, the question whether we would discover more patients with occult metastases remains. If we accept the concept of the sentinel lymph node [27, 28] that if there are no metastases in the sentinel lymph node that there are also no metastases in the other lymph nodes, the only question remains if the correct sentinel lymph node was selected. With the use of radiocolloid and concurrent intraoperative use of methylene blue, the identification is very reliable [29]. Even with the surgical method, when we remove only the sentinel lymph nodes, we discover many occult metastases with serial slices [30] that we otherwise would not have. This method has some weaknesses, mainly the possibility of missed metastases intraoperatively which are discovered afterwards [31] leading to an additional surgical procedure. Another potential problem is that we do not remove the true sentinel lymph node, which can happen due to a limited access and consequent inability to visualize the lymph flow by methylene blue. We may only see if the lymph node has stained or not, but we may not see if any other lymph node before has stained as well. In selective dissection where to gain access, we raise the entire subplatysmal skin flap, and we have a good visualization of the lymph drainage from the area surrounding the tumor. The visualization is also good when we use the gamma-ray detector to identify the lymph nodes which we marked on the skin when performing the scintigraphy. We often see many smaller lymph nodes on a very narrow area and if we would rely on the gamma-ray detector only, we could easily misidentify the sentinel lymph node. We can observe that after the removal of the sentinel lymph node, only the patients with regional recurrent disease have a very poor prognosis [32]. The possibility for recurrence is greatly increased if we have a larger number of metastatic sentinel lymph nodes. Micrometastases and isolated tumor cells do not have a larger influence on the possible recurrence [32]. The reason for this could be an overlooked true sentinel lymph node and the possible changes of lymph drainage and metastases found at unpredictable locations later on. With selective dissection where we remove the lymph nodes from the region of the sentinel lymph node's location and two adjoining regions, there is basically no chance to not remove all the lymph nodes with metastases, especially if adequate ultrasound or CT

Another question is if all of the metastases of the removed lymph nodes are found. If with serial slices and immunohistochemical staining in the sentinel lymph node we discover the metastases, there is also a possibility that the metastases are present in other lymph nodes. In 7 out of 18 patients, these metastases were discovered, even with the classical examination only. Therefore, there is a small chance that we have not discovered all of the micrometastases and

diagnostics were performed preoperatively.

90 Cancer Survivorship

We can see that we do not have a method to preoperatively prove smaller metastases of the lymph nodes of the patients with the cancer of the upper airways and upper digestive tract. Even after a selective dissection with classical histopathological methods of removed lymph nodes, around 10% of the patients with metastases are missed. With a somewhat modified use of the concept of the sentinel lymph node, we can significantly decrease this number by discovering basically all of the metastases of the regional lymph nodes. A prospective study is needed to prove if the smaller metastases have an influence on the patient's survival and if they should be treated with additional adjuvant radiotherapy. However, there is an ethical question of not providing additional therapy to the patients with smaller metastases in numerous lymph nodes, despite the fact that they would not be receiving it with the classical examination of the removed lymph nodes anyway. There are also regional recurrences in the patients who have had a selective dissection, and the pathologist did not find the metastases in the removed lymph nodes. The percentage of these recurrences indicates that this might be these unrecognized metastases.
