Original article: role of adjuvant chemotherapy in a perioperative chemotherapy regimen for gastric cancer

Downstaging Effect Rather than the Full Intended Cycles of Perioperative Chemotherapy Determines the Value of Adjuvant Chemotherapy in Gastric Cancer

BACKGROUND

Perioperative chemotherapy is the standard treatment modality for locally advanced gastric cancer. However, the efficacy and indication of adjuvant chemotherapy in patients who have already received neoadjuvant chemotherapy remain unclear. This study aims to explore the association between adjuvant chemotherapy with patient prognosis in those who have received neoadjuvant chemotherapy plus D2 gastrectomy in a real-world setting, and whether this association is affected by the duration of neoadjuvant treatment.

PATIENTS AND METHODS

A total of 174 patients with cT3-4N+ gastric cancer who had received neoadjuvant chemotherapy plus D2 radical gastrectomy were included in the study. Kaplan-Meier curves and log-rank tests were used to assess and compare the survival outcomes between patients who received adjuvant therapy and those who did not.

RESULTS

Patients who were younger age, had a lower American Society of Anesthesiologists (ASA) grade, did not experience postoperative complication, and received fewer than six cycles of neoadjuvant chemotherapy were more likely to receive adjuvant chemotherapy, rather than those with advanced ypTNM stage or poor tumor regression grade. Patients who received adjuvant therapy had a better overall survival (OS) (2-year OS rate 86.2% versus 64.1%, p = 0.002). Adjuvant therapy was associated with longer survival in patients who remained ypTNM stage III despite receiving at least six cycles of neoadjuvant chemotherapy. However, there was no significant longer survival observed in patients with ypTNM stages 0-II receiving adjuvant chemotherapy, even when they received less than six cycles of neoadjuvant chemotherapy.

CONCLUSIONS

Patients with locally advanced gastric cancer may still need adjuvant chemotherapy, even after receiving neoadjuvant chemotherapy. The value of adjuvant chemotherapy after neoadjuvant chemotherapy depends more on the actual downstaging effect achieved after neoadjuvant chemotherapy, rather than the completion of "full intended" cycles of perioperative treatment.

Impact of Postoperative Chemotherapy in Patients with Gastric/Gastroesophageal Adenocarcinoma Treated with Perioperative Chemotherapy

Perioperative chemotherapy is the standard of care for patients undergoing curative resection for gastroesophageal adenocarcinoma. However, less than 50% of patients complete postoperative chemotherapy, and the added benefit to preoperative chemotherapy remains unclear. The aim of this study was to compare disease-free and overall survival (DFS and OS) in patients with perioperative chemotherapy to those who received preoperative chemotherapy only. In addition, a current literature overview is included. This multicenter, retrospective case series included 124 patients with gastroesophageal adenocarcinoma undergoing potentially curative resection and receiving pre- or perioperative chemotherapy between 2006 and 2010. Histopathological, demographic, clinical, and survival data were used to identify the impact of perioperative vs. preoperative chemotherapy on DFS and OS. Patients with perioperative chemotherapy had significantly improved DFS and OS (median DFS 28.0 months; 95%CI 0–62.4 vs. 19.0 months; 95%CI 10.5–27.5; p = 0.008 and median OS 35.7 months; 95%CI 0–73.6 vs. 19.2 months; 95%CI 7.8–30.4; p = 0.002). However, in contrast to patients with tumor-free lymph nodes at the time of resection, patients with positive lymph node status did not significantly benefit from additional postoperative chemotherapy in subgroup analysis. Further studies are encouraged to investigate optimal adjuvant treatment strategies for primary chemotherapy-resistant patients.

Duration of Perioperative Chemotherapy in Locally Advanced Gastric Cancer: A "Less Is More" Question When ypN0 Is Achieved

Backgrounds

Perioperative chemotherapy (PEC) and neoadjuvant chemotherapy (NAC) have become a vital part of locally advanced gastric cancer (LAGC) treatment, but the optimal duration of PEC has not been studied. The aim of this study was to demonstrate the possibility of duration reduction in PEC in the adjuvant chemotherapy (AC) phase for ypN0 patients.

Methods

We included LAGC patients who achieved ypN0 after NAC in our institution from 2005 to 2018. The risk/benefit of AC and other covariates were majorly measured by overall survival (OS) and progression-free survival (PFS). We developed a survival-tree-based model to determine the optimal PEC duration for ypN0 patients in different classes.

Results

A total of 267 R0 resection patients were included. There were 55 patients who did not receive AC. The 5-year OS was 74.34% in the non-AC group and 83.64% in the AC group with a significant difference (p = 0.012). Multivariate Cox regression revealed that both AC (AC vs. non-AC: HR, 0.49; 95%CI, 0.27–0.88; p = 0.018) and ypT stages (ypT3-4 vs. ypT0-2: HR, 2.00; 95%CI, 1.11–3.59; p = 0.021) were significant protective/risk factors on patients OS and PFS. A decision tree model for OS indicated an optimal four to six cycles of PEC, which was recommended for ypT0-2N0 patients, while a minimum of five PEC cycles was recommended for ypT3-4N0 patients.

Conclusion

AC treatment is still necessary for ypN0. The duration reduction could be applied for the ypT0-2N0 stage patients but may not be suitable for higher ypT stages and beyond. A multicenter-based study is required.

S1 versus Doublet Regimens as Adjuvant Chemotherapy in Patients with Advanced Gastric Cancer after Radical Surgery with D2 Dissection-A Propensity Score Matching Analysis

BACKGROUND

Fluoropyrimidine- and platinum-based doublet regimen is the standard treatment of adjuvant chemotherapy (AC) for gastric cancer (GC). Our study aims to compare S1 with doublet regimens as AC in patients with advanced GC after radical surgery with D2 dissection.

METHODS

Patients who were diagnosed with GC and underwent a curative surgery with D2 dissection followed by AC were enrolled into our study. A propensity score matching analysis was performed to reduce the selection bias. Kaplan-Meier curves were estimated for recurrence-free survival (RFS) and overall survival (OS). Cox regression models were conducted for survival.

RESULTS

After propensity sore matching, 64 patients with S1 and 64 patients with doublet regimens were identified. The median RFS (p = 0.355) and OS (p = 0.309) were both insignificant between S1 and ST. Cox regression analysis demonstrated that pathologic stage and lymph node ratio (LNR) were independently correlated with survival. Patients were then stratified into low risk and high risk groups. The median RFS (p < 0.001) and OS (p < 0.001) had significant differences between low risk and high risk. In the high-risk group, doublet regimens were strongly associated with survival (p = 0.020) as compared with S1. While in the low-risk group, doublet regimen and S1 did not have statistically different survival benefits.

CONCLUSIONS

Our study demonstrated that doublet regimens are superior to S1 in high-risk groups, and that survival outcomes are similar between doublet regimens and S1 in low-risk groups. Our prognostic model might have clinical implications for AC.

Long noncoding AFAP1-antisense RNA 1 is upregulated and promotes tumorigenesis in gastric cancer

Long noncoding RNA serves important roles in gastric cancer (GC). However, the prognostic significance and tumorigenesis effect of AFAP1-antisense RNA 1 (AS1) in GC remain to be clarified. The present study was conducted in order to determine the expression level of AFAP1-AS1 by reverse transcription-quantitative polymerase chain reaction. It was demonstrated that AFAP1-AS1 expression level was higher in GC tissues in comparison with adjacent tissues. By analyzing 66 GC tissue specimens, AFAP1-AS1 expression level was found to be markedly associated with tumor size, clinical stage and differentiation. By performing multivariate Cox regression test, AFAP1-AS1 expression level was confirmed to be an independent factor for poor prognosis in patients with GC. Furthermore, SGC-7901 and BGC-823 cells were used for further investigation following transfection of an AFAP1-AS1 short hairpin RNA lentiviral vector. Knockdown of AFAP1-AS1 significantly inhibited GC cell proliferation, migration and invasion abilities in vitro. Finally, nude mice experiments confirmed that downregulation of AFAP1-AS1 in GC cells suppressed tumor growth in vivo. In conclusion, the results of the present study suggested that AFAP1-AS1 may serve as a valuable prognostic indicator and therapeutic target for GC.

Impact of lymph node ratio in selecting patients with resected gastric cancer for adjuvant therapy

BACKGROUND

The impact of adjuvant chemotherapy and chemo-radiation therapy in the treatment of resectable gastric cancer remains varied. We sought to define the clinical impact of lymph node ratio on the relative benefit of adjuvant chemotherapy or chemo-radiation therapy among patients having undergone curative-intent resection for gastric cancer.

METHODS

Using the multi-institutional US Gastric Cancer Collaborative database, 719 patients with gastric adenocarcinoma who underwent curative-intent resection between 2000 and 2013 were identified. Patients with metastasis or an R2 margin were excluded. The impact of lymph node ratio on overall survival among patients who received chemotherapy or chemo-radiation therapy was evaluated.

RESULTS

Median patient age was 65 years, and the majority of patients were male (56.2%). The majority of patients underwent either subtotal (40.6%) or total gastrectomy (41.0%), with the remainder undergoing distal gastrectomy or wedge resection (18.4%). On pathology, median tumor size was 4 cm; most patients had a T3 (33.0%) or T4 (27.9%) lesion with lymph node metastasis (59.7%). Margin status was R0 in 92.5% of patients. A total of 325 (45.2%) patients underwent resection alone, 253 (35.2%) patients received 5-FU or capecitabine-based chemo-radiation therapy, whereas the remaining 141 (19.6%) received chemotherapy. Median overall survival was 40.9 months, and 5-year overall survival was 40.3%. According to lymph node ratio categories, 5-year overall survival for patients with a lymph node ratio of 0, 0.01-0.10, >0.10-0.25, >0.25 were 54.1%, 53.1 %, 49.1 % and 19.8 %, respectively. Factors associated with worse overall survival included involvement of the gastroesophageal junction (hazard ratio 1.8), T-stage (3-4: hazard ratio 2.1), lymphovascular invasion (hazard ratio 1.4), and lymph node ratio (>0.25: hazard ratio 2.3; all P < .05). In contrast, receipt of adjuvant chemo-radiation therapy was associated with an improved overall survival in the multivariable model (versus resection alone: hazard ratio 0.40; versus chemotherapy: hazard ratio 0.45, both P < .001). The benefit of chemo-radiation therapy for resected gastric cancer was noted only among patients with lymph node ratio >0.25 (versus resection alone: hazard ratio R 0.34; versus chemotherapy: hazard ratio 0.45, both P < .001). In contrast, there was no noted overall survival benefit of chemotherapy or chemo-radiation therapy among patients with lymph node ratio ≤0.25 (all P > .05).

CONCLUSION

Adjuvant chemotherapy or chemo-radiation therapy was utilized in more than one-half of patients undergoing curative-intent resection for gastric cancer. Lymph node ratio may be a useful tool to select patients for adjuvant chemo-radiation therapy, because the benefit of chemo-radiation therapy was isolated to patients with greater degrees of lymphatic spread (ie, lymph node ratio >0.25).