Association between adjuvant chemotherapy and survival in patients with rectal cancer and pathological complete response after neoadjuvant chemoradiotherapy and resection

Abstract

Background For patients with locally advanced rectal cancer (LARC), it is unclear whether neoadjuvant chemoradiotherapy-induced pathologic complete response (pCR) individuals would further benefit from adjuvant chemotherapy (ACT). Methods The pCR individuals who received different ACT cycles were paired by propensity score matching. Overall survival (OS), disease-free survival (DFS), local recurrence-free survival (LRFS), and distant metastasis-free survival (DMFS) were calculated by Kaplan–Meier and log-rank test. Results In total, 1041 pCR individuals were identified from 5567 LARC cases. Specifically, 303 pCR cases had no ACT treatment, and 738 pCR patients received fluoropyrimidine-based ACT (median, 4 cycles) treatment. After 1:3 propensity score matching, 297 cases without ACT treatment were matched to 712 cases who received ACT treatment. Kaplan–Meier analysis showed that pCR individuals treated with or without ACT had the similar 3-year outcome (OS, DFS, LRFS and DMFS) (all P > 0.05). Moreover, the pCR patients received different ACT cycle(s) (0 vs. 1–4 cycles, 0 vs. ≥5 cycles) had comparable 3-year OS, DFS, LRFS and DMFS (all P > 0.05). In stratified analysis, ACT treatment did not improve 3-year survival (OS, DFS, LRFS and DMFS) for the baseline high-risk (cT3–4/cN1–2) subgroup patients (all P > 0.05). Conclusion ACT, which did not improve survival, is unnecessary to neoadjuvant treatment-induced pCR LARC patients. Trial registration 2019ZSLYEC-136 (24-6-2019).

Nomogram to Predict Distant Metastasis Probability for Pathological Complete Response Rectal Cancer Patients After Neoadjuvant Chemoradiotherapy

“… 13 But several prospective studies indicated that ACT is unnecessary for NACRT-induced pCR LARC patients. 14 , 30 , 31 Agreeing with their study, patients with or without ACT had comparable OS rates and DMFS rates in our data. In stratified groups, patients with cT 3-4 , cN + and high risks to DM had no obvious benefit from ACT.…”

“… 12 , 13 However, a multi-center retrospective study including 1041 LARC patients with pCR implied that similar OS, local recurrence-free survival (LRFS), distant metastasis-free survival (DMFS) and disease-free survival (DFS) were observed between the ACT group and the non-ACT group. 14 Obviously, the true value of ACT in pCR patients remains to be determined.…”

Associations between clinical characteristics and tumor response to neoadjuvant chemoradiotherapy in rectal cancer

“…In our study, there were some advantages and disadvantages. First, considering that the pCR patients were the main study objects in previous studies, 12 , 13 , 18 , 20 we also included ypT1–2N0 patients and our study participants also showed a good prognosis and, more importantly, were potential candidates for local excision selection. 9 Moreover, to the best of our knowledge, this was the largest‐scale study to analyze the correlation of clinicopathological characteristics including different nCT strategies and the intervals to surgery and good response; furthermore, we attained an answer as to whether ACT was necessary for these patients.…”

“…8,11 Furthermore, among patients who downstaged to a pathological good response, the necessity of adjuvant chemotherapy treatment (ACT) was also deemed controversial. 5,7,[19][20][21][22] Several studies have reported that no survival benefits exist in concert with ACT among these good responders. 20,22 Nevertheless, other studies have shown that the delivery of ACT achieved an improvement in the DFS, thus supporting the necessity of ACT.…”

“… 5 , 7 , 19 , 20 , 21 , 22 Several studies have reported that no survival benefits exist in concert with ACT among these good responders. 20 , 22 Nevertheless, other studies have shown that the delivery of ACT achieved an improvement in the DFS, thus supporting the necessity of ACT. 5 , 19 , 21 However, these studies were often either small in scale or did not consider the preoperative clinical characteristics, limiting their ability to draw valid conclusions.…”