Personalized treatment strategies for locally advanced rectal cancer with using modified short-course preoperative chemoradiotherapy

Introduction: The oncologic outcomes of locally advanced rectal cancer (1)resectable<T3N0-1> 2)borderline resectable<T4orN2>）is quite different according to the tumor advancement. We demonstrate the oncologic outcomes of our personalized treatment strategies for locally advanced rectal cancer with utilizing short course radiotherapy(SRT)
Patients and Methods:1)resectable:(between2007 and 2018.n=162 patients) we selected modified SRT(25Gy/10fraction/5days+S-1 or Xeloda)2)borderline resectable：untill 2011,we selected long course radiotherapy(LCRT).After 2012,we selected Total neoadjuvant therapy (TNT; FOLFOX or SOX)+SRT(n=58 patients).We performed lateral lymph node dissection(LLND) only on the patients with swelling of 6 mm after pre-treatment MRI .
Result:1)resectable; T down staging;47%, ypN0;67%, pCRrate;7%,sphincter preserving rate;96%, 5-yr LFS;94%,RFS;79%,OS;90%.leakage rates 7% 2)borderline resectable;T down staging;71%,ypN0;61%,pCRrate;11%,sphincter preserving rate92%..3-yr LFS;84%,RFS;51%,OS;74%.This result is better than LCRT(3-yrLFS;81%,RFS;51%,OS;74%).Selective LLND provides a good local control rate of 90% with down-staging, but about 14% of cases who were still positive for lymph node metastasis after CRT had a poor prognosis due to distant metastasis recurrence.In addition, the cases still positive for mesotoneal and LLN metastasis recurred metastasis within 6 months in all cases, and the prognosis was poorer than that of stage Ⅳ．
Conclusion: As mentioned 1)modified SRT for resectable locally advanced rectal cancer was acceptable oncologic results 2)Because full dose chemotherapy can be done before surgery,it was suggested that TNT+SRT might be a useful treatment regimen borderline cases. However, further examination of the systemic chemotherapy regimen for the poor prognosis case was considered necessary.