Lateral lymph node recurrence and induction chemotherapy 67 CHAPTER 4 Basically, there are two different applications of the LLND, combined with TME: the ‘prophylactic LLND’ and the ‘indicated LLND’, if the LLNs are enlarged on MRI. The prophylactic LLND used to be performed in Japan in all low and locally advanced tumours, irrespective of LLN size; however, nowadays, it is gradually being replaced by nCRT regimens, which have been shown to give similar local control, without the morbidity associatedwith the operation.9,16 The oncologic results of the JCOG0212 trial17 are expected soon, inwhich prophylactic LLND is comparedwithTME alone in patients with LLN up to 10 mm in size. As no neoadjuvant treatment is administered to patients in the TME arm, we expect that local control will be better in the LLND arm. However, in the case of obvious LLN metastases, more evidence has arisen that nCRT alone might not be sufficient to prevent lateral regrowth. Tumour height and definition of enlarged LLN vary per study, but in patients with enlarged LLNs (>5/10mm) who received nCRT + TME, 5-year latLRs have shown to be between 10 and 80 percent.18–20 In addition, approximately 40 percent of patients who had a recurrence had no distant spread, suggesting that the recurrence was still localized disease. In several studies in patients with enlarged LLNs, after nCRT+ LLND, in 40–66 percent of the cases tumour cells could be found in the LLNs, showing that these cannot be completely sterilized.21–23 Interestingly, in one of these studies,23 5-year recurrence-free survival rates after nCRT +LLND (showing 66 percent LLNmetastases) was similar (84 percent) to patients who had unsuspected nodes and thus only had nCRT + TME (75 percent). In the West, there are two things to remember. First, we should not ignore the lateral compartment in the prophylactic setting. In the case of low, lymph node positive or locally advanced tumours, the lateral compartment should be included in the radiation target volume, especially in IMRT. Second, in the case of obvious LLN involvement, nCRT is not enough, as latLR occurs in up to 80 percent of these patients. The idea that lateral spread is always metastasized disease has been shown to be untrue, and there might be cure for these patients by combining nCRT with an indicated LLND. Conclusions This is the first study to describe a cohort of latLRs. Although this study has its weaknesses with regard to low patient numbers and inconsistent administration of ICT, it has a clear message—ICT should be considered in latLRs in order to achieve an R0 resection.
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