Desley van Zoggel

Chapter 4 66 Discussion This studyevaluated the treatment of 51patientswith latLR, froma total of 214patientswith LRRCwhounderwentmultimodalitytreatment inournational tertiaryreferral centre inthe last 10 years. Thirteen (25 percent) of these patients were treated with ICT prior to CRT. A major finding of this study was that ICT increases the R0 resection rate up to 85 percent. This is the only factor that improves LRR andOS rates in these patients, as 5-year OS after an R+ resectionwas only 10.3 percent comparedwith 66.8 percent after an R0 resection. No factors that could bias the use of ICT were observed. There is of course a time factor, as ICT was gradually introduced after 2007. However, we do not believe there was a difference in surgical management of these recurrences as both surgeons operating on all LRRCs in our hospital have been conducting these operations since the nineties and have not changed their surgical approach in latLR. The role of ICT is being widely investigated in the treatment of primary rectal cancer13–15 but has not been previously described in the treatment of LRRC. Our study shows that pCR is induced in 31 percent of latLRs, which is strikingly significant comparedwith the 8 percent without it, even in these small patient numbers. However, there iswide variation in the administration of further chemotherapy after a good initial response on PET–CT and/or MRI after three to four courses. It is not known whether it is better to apply a ‘split-course’ regimen, meaning that after the initial three to four courses of ICT and CRT the rest of the courses are administered in thewaiting periodbefore surgery, or a ‘doublecourse’ regimen, when up to six courses of chemotherapy are administered before CRT. Our preference goes towards a split regimen in responders as the majority of responses will happenduring thefirst courses, and the chemotherapy in thewaiting periodwill then not delay surgery in any way. In irresectable recurrences (an intensified) double-course regimen would be preferable in the hope that they become resectable. Currently, we are clarifying the treatment protocols to make them uniform. This studywas unable toelucidate anything regarding thepreventionof latLRs. Our study confirms the observation from Japan that LLN involvement mainly occurs in locally advanced and low tumors.7,8 However, although we know that 17 percent of patients in this study had not been previously irradiated, we were not able to analyse whether the other 83 percent who were irradiated also received the full target volume on the lateral compartment, becausemost patients were referred to our centre and had their previous treatment in other centres in The Netherlands. Nonetheless, if these data were known, they would be of no help in determining howmany patients would have to be irradiated in order to prevent latLRs.