Association of survival with adjuvant chemotherapy in patients with stage IB gastric cancer: a multicentre, observational, cohort study

Background

Recurrence following radical resection in patients with stage IB gastric cancer (GC) is not uncommon. However, whether postoperative adjuvant chemotherapy could reduce the risk of recurrence in stage IB GC remains contentious.

Methods

We collected data on 2110 consecutive patients with pathologic stage IB (T1N1M0 or T2N0M0) GC who were admitted to 8 hospitals in China from 2009 to 2018. The survival of patients who received adjuvant chemotherapy was compared with that of postoperative observation patients using propensity score matching (PSM). Two survival prediction models were constructed to estimate the predicted net survival gain attributable to adjuvant chemotherapy.

Findings

Of the 2110 patients, 1344 received adjuvant chemotherapy and 766 received postoperative observation. Following the 1-to-1 matching, PSM yielded 637 matched pairs. Among matched pairs, adjuvant chemotherapy was not associated with improved survival compared with postoperative observation (OS: hazard ratio [HR], 0.72; 95% CI, 0.52-1.00; DFS: HR, 0.91; 95% CI, 0.64-1.29). Interestingly, in the subgroup analysis, reduced mortality after adjuvant chemotherapy was observed in the subgroups with elevated serum CA19-9 (HR, 0.22; 95% CI, 0.08-0.57; P = 0.001 for multiplicative interaction), positive lymphovascular invasion (HR, 0.32; 95% CI, 0.17-0.62; P < 0.001 for multiplicative interaction), or positive lymph nodes (HR, 0.17; 95% CI, 0.07-0.38; P < 0.001 for multiplicative interaction). The survival prediction models mainly based on variables associated with chemotherapy benefits in the subgroup analysis demonstrated good calibration and discrimination, with relatively high C-indexes. The C-indexes for OS were 0.74 for patients treated with adjuvant chemotherapy and 0.70 for patients treated with postoperative observation. Two nomograms were built from the models that can calculate individualized estimates of expected net survival gain attributable to adjuvant chemotherapy.

Interpretation

In this cohort study, pathologic stage IB alone was not associated with survival benefits from adjuvant chemotherapy compared with postoperative observation in patients with early-stage GC. High-risk clinicopathologic features should be considered simultaneously when evaluating patients with stage IB GC for adjuvant chemotherapy.

Funding

National Natural Science Foundation of China; the National Key R&D Program of China.

A novel nomogram for identifying candidates for adjuvant chemotherapy in patients with stage IB gastric adenocarcinoma

BACKGROUND

The purpose of this research was to construct a novel predictive nomogram to identify specific stage IB gastric adenocarcinoma (GAC) populations who could benefit from postoperative adjuvant chemotherapy (ACT).

METHOD

Between 2004 and 2015, 1889 stage IB GAC patients were extracted from the Surveillance, Epidemiology, and End Results (SEER) program database. Then Kaplan-Meier survival analysis, univariate and multivariable Cox analyses, and univariate and multivariable logistic analyses were implemented. Finally, the predictive nomograms were constructed. The methods of area under the curve (AUC), calibration curve, and decision curve analysis (DCA) were used to validate the clinical effectiveness of the models.

RESULTS

Of these patients, 708 cases underwent ACT, while the other 1181 patients didn't receive ACT. After PSM, the patients in the ACT group presented a longer median overall survival (133 vs. 85 months, p = 0.0087). Among the ACT group, 194 (36.0%) patients achieving more prolonged overall survival than 85 months were regarded as the beneficiary population. Then the logistic regression analyses were performed, and age, gender, marital status, primary site, tumor size, and regional nodes examined were included as predicting factors to construct the nomogram. The AUC value was 0.725 in the training cohort and 0.739 in the validation cohort, which demonstrated good discrimination. And calibration curves indicated ideal consistency between the predicted and observed probabilities. Decision curve analysis presented a clinically useful model. Furthermore, the prognostic nomogram predicting 1-, 3-, and 5-year cancer-specific survival presented good predictive ability.

CONCLUSION

The benefit nomogram could guide clinicians in decision-making and selecting optimal candidates for ACT among stage IB GAC patients. And the prognostic nomogram presented great prediction ability for these patients.

Mixed Histologic Type is a Risk Factor for Lymph Node Metastasis in Submucosal Invasive Early Gastric Cancer

INTRODUCTION

The treatment regimen for early gastric cancer (EGC) with mixed histologic type remains controversial. We aimed to clarify the relationship between mixed histologic type and lymph node metastasis (LNM) in EGC, with emphasis on submucosal invasive EGC.

METHODS

We collected data on 730 consecutive EGC patients at Nanjing Drum Tower hospital between June 2010 and May 2019. Risk factors of LNM and overall survival were analyzed to compare the prognostic differences between different histologic types.

RESULTS

Mixed-type EGC patients had higher LNM rates than differentiated-type patients (29.2 % versus 10.6 %, P < 0.001), while no significant difference was found between mixed-type and undifferentiated-type EGC patients (29.2% versus 24.0%, P = 0.225). Multivariate analyses identified tumor location (cardiac and bottom versus antrum), larger tumor size, submucosal invasion, histologic differentiation (undifferentiated-type, mixed-type versus differentiated-type), and lymphovascular invasion as independent risk factors for LNM in EGC patients. Subgroup analysis further elucidated that mixed histologic type was associated with LNM in submucosa invasive EGC, but not in mucosa-confined EGC. There was no statistical significance in overall survival and disease-specific survival of submucosal invasive EGC patients who underwent radical gastrectomy with lymphadenectomy between different histologic types (P = 0.151).

CONCLUSIONS

Mixed histologic type may be an independent risk factor for LNM in submucosal invasive EGC. Curative resection with lymphadenectomy should be considered the appropriate treatment for submucosal invasive EGC with mixed histologic type.

A Novel Method for Dynamically Assessing the Prognosis of Patients with pT1 Gastric Cancer: A Large Population-Based Dynamic Prognostic Analysis

Background

While early gastric cancer (EGC) patients are likely to experience relatively long postoperative survival, certain disease-related findings are associated with a poorer prognosis. This study sought to develop and validate a novel predictive model capable of estimating conditional disease-specific survival (CDSS) in EGC patients.

Methods

A total of 3016 patients diagnosed with pT1NxM0 GC after gastrectomy between 1998 and 2016 were selected from the Surveillance, Epidemiology, and End Results (SEER) database and were separated into training and validation cohorts. Kaplan‒Meier curves and log-rank tests were employed to evaluate DSS, after which univariate and multivariate Cox regression analyses were used to construct a predictive nomogram and to estimate CDSS at 1, 2, and 3 years postoperatively in these patients.

Results

In the training cohort, the 3-year CDSS rose from 89.1% to 94.6% from 0 to 5 years postoperatively, while the 5-year CDSS rose from 84.5% to 92.0%. Cox regression analyses led to the construction of a nomogram that was able to reliably predict 3- and 5-year CDSS at 1, 2, and 3 years postoperatively (all P < 0.05) based upon patient age, tumor size, pT stage, pN stage, and the number of retrieved lymph nodes. This model exhibited good discriminative power in the training and validation cohorts (concordance index: 0.791 and 0.813, respectively), and nomogram calibration curves confirmed that actual and predicted survival outcomes were close to one another.

Conclusions

We herein developed a nomogram capable of accurately predicting the CDSS of EGC patients that had survived for multiple years after undergoing surgery.

Management of Superficial Esophageal Squamous Cell Carcinoma and Early Gastric Cancer following Non-Curative Endoscopic Resection

According to the European and Japanese guidelines, additional treatment is recommended for cases of superficial esophageal squamous cell carcinoma (ESCC) and early gastric cancer (EGC) that do not meet the curability criteria for endoscopic resection (ER), i.e., non-curative ER, owing to the risk of lymph node metastasis (LNM). However, the rates of LNM in such cases were relatively low (e.g., 8% for EGC). Several recent advances have been made in this field. First, pathological risk stratification for metastatic recurrence following non-curative ER without additional treatment was developed for both superficial ESCC and EGC. Second, the pattern of metastatic recurrence and prognosis after recurrence following non-curative ER without additional treatment was found to be considerably different between superficial ESCC and EGC. Third, a combination of ER and selective chemoradiotherapy was developed as a minimally invasive treatment method for clinical T1b-SM ESCC. These findings may help clinicians decide the treatment strategy for patients following non-curative ER; however, for optimal therapeutic decision-making in such patients, it is also important to predict the prognosis other than SESCC or EGC and impaired quality of life. Thus, a novel algorithm that considers these factors, as well as metastatic recurrence, should be developed.

The role of chemotherapy in patients with stage IB gastric adenocarcinoma: a real-world competing risk analysis

Background

This study aimed to investigate the potential effect of adjuvant chemotherapy in patients diagnosed with stage IB gastric adenocarcinoma (GAC).

Method

A total of 1727 patients were included in the Surveillance, Epidemiology, and End Results (SEER) database from 2004 to 2015 and divided into the chemotherapy and no-chemotherapy groups. Then, the methods of Kaplan-Meier analysis, propensity score matching (PSM), and competing risk analysis were implemented.

Results

After PSM, no significant difference was found in the chemotherapy and no-chemotherapy groups in overall survival (OS) (p=0.4) and cancer-specific survival (CSS) (p=0.12) in survival curves. The competing risk analysis presented that the 5-year cumulative incidence of cancer-specific death (CSD) was significantly lower in patients receiving chemotherapy (11.5% vs. 20.8%, p=0.007), while no significant discrepancy was observed in other causes of death (OCD) in both groups (10.6% vs. 10.9%, p=0.474). Multivariable competing risks regression models presented a significant correlation between chemotherapy and CSD (HR, 0.51; 95%CI, 0.31–0.82; p=0.007).

Conclusion

The stage IB GAC patients can benefit from adjuvant chemotherapy based on this competing risk analysis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-022-02591-5.

Prognostic Nomogram for Early Gastric Cancer After Surgery to Assist Decision-Making for Treatment With Adjuvant Chemotherapy

Background: Most patients with early gastric cancer (EGC) can achieve a better 5-year survival rate after endoscopic resection or surgery. However, indications for adjuvant chemotherapy (ACT) after surgery have not yet been determined.

Methods: A total of 4,108 patients with EGC diagnosed in 2004–2016 were retrospectively analyzed using the Surveillance, Epidemiology, and End Results (SEER) database. Of these, 3,521 patients received postoperative ACT and 587 patients did not. Propensity score matching was used to balance the two groups’ confounding factors. Kaplan-Meier method was utilized to perform survival analysis. Log-rank test was used to compare the differences between survival curves. Cox proportional-hazards regression model was used to screen independent risk factors and build a nomogram for the non-ACT group. The X-tile software was employed to artificially divide all patients into low-, moderate-, and high-risk groups according to the overall survival score prediction based on the nomogram. A total of 493 patients with EGC diagnosed between 2010 and 2014 in our hospital were included for external validation.

Results: Multivariate analysis found that age, sex, race, marital status, primary site, surgical extent, and metastatic lymph node ratio in the non-ACT group were independent prognostic factors for EGC and were included in the construction of the nomogram. The model C-index was 0.730 (95% confidence interval: 0.677–0.783). The patients were divided into three different risk groups based on the nomogram prediction score. Patients in the low-risk group did not benefit from ACT, while patients in the moderate- and high-risk groups did. External validation also demonstrated that moderate- and high-risk patients benefited from ACT.

Conclusion: The study nomogram can effectively evaluate postoperative prognosis of patients with EGC. Postoperative ACT is therefore recommended for moderate- and high-risk patients, but not for low-risk patients.

Single patient classifier as a prognostic biomarker in pT1N1 gastric cancer: Results from two large Korean cohorts

Objective

Benefits of adjuvant treatment in pT1N1 gastric cancer (GC) remain controversial. Additionally, an effective biomarker for early GC is the need of the hour. The prognostic and predictive roles of single patient classifier (SPC) were validated in stage II/III GC. In this study, we aimed to elucidate the role of SPC as a biomarker for pT1N1 GC.

Methods

The present retrospective biomarker study (NCT03485105) enrolled patients treated for pT1N1 GC between 1996 and 2012 from two large hospitals (the Y cohort and S cohort). For SPC, mRNA expression of four classifier genes (GZMB, WARS, SFRP4 and CDX1) were evaluated by real-time reverse transcription-polymerase chain reaction assay. The SPC was revised targeting pT1 stages and the prognosis was stratified as high- and low-risk group by the expression of SFRP4, a representative epithelial-mesenchymal transition marker.

Results

SPC was evaluated in 875 patients (n=391 and 484 in the Y and S cohorts, respectively). Among 864 patients whose SPC result was available, 41 (4.7%) patients experience GC recurrence. According to revised SPC, 254 (29.4%) patients were classified as high risk [123 (31.5%) and 131 (27.1%) in the Y and S cohorts, respectively]. The high risk was related to frequent recurrence in both Y and S cohort (log-rank P=0.023, P<0.001, respectively), while there was no difference byGZMB and WARS expression. Multivariable analyses of the overall-cohort confirmed the high risk of revised SPC as a significant prognostic factor [hazard ratio (HR): 4.402 (2.293−8.449), P<0.001] of GC. A significant difference was not detected by SPC in the prognosis of patients in the presence and absence of adjuvant treatment (log-rank P=0.670).

Conclusions

The present study revealed the revised SPC as a prognostic biomarker of pT1N1 GC and suggested the use of the revised SPC for early-stage GC as like stage II/III.

Microsatellite Instability and Effectiveness of Adjuvant Treatment in pT1N1 Gastric Cancer: A Multicohort Study

BACKGROUND

Microsatellite status is a prognostic biomarker in advanced gastric cancer. This retrospective study aimed to investigate the usefulness of microsatellite status in predicting prognosis and response to adjuvant treatment in pT1N1 gastric cancer.

PATIENTS AND METHODS

Among 875 patients who underwent radical gastrectomy for pT1N1 gastric cancer at two tertiary hospitals, 838 with available microsatellite instability (MSI) data were included and classified into two groups according to microsatellite status: microsatellite stable (MSS) and MSI-high (MSI-H). Recurrence-free survival rate and risk factors for tumor recurrence were analyzed.

RESULTS

Of 838 gastric cancer patients, 100 (11.9%) were MSI-H and 307 (36.6%) received adjuvant treatment. During median follow-up of 70 months, 42 (5.0%) patients experienced gastric cancer recurrence; hematogenous recurrences were the most common (45.2%). Recurrence-free survival was similar in the MSS and MSI-H groups (p = 0.27), and adjuvant treatment did not show an oncological benefit over surgery alone for pT1N1 gastric cancer (p = 0.53). On univariate analysis, age, operation period, and Lauren classification were significantly associated with tumor recurrence, while adjuvant treatment and MSI status were not associated with tumor recurrence. On multivariate analysis, MSI status was not associated with tumor recurrence, and adjuvant treatment worsened the tumor recurrence risk [hazard ratio (HR) 2.373, 95% confidence interval (CI) 1.125-5.006, p = 0.023).

CONCLUSION

MSI status may not be a prognostic factor for tumor recurrence or a predictor of response to adjuvant treatment in pT1N1 gastric cancer patients. Considering that the effect of adjuvant treatment to decrease the risk of tumor recurrence is not clear, it may not be indicated in pT1N1 patients.

The Effectiveness of Postoperative Chemotherapy on pT1bN0 and pT2N0 Gastric Cancer Patients with Risk Factors: An International Dual-Center Analysis

PURPOSE

This study aimed to investigate the effectiveness of postoperative chemotherapy in pT1bN0 and pT2N0 gastric cancer patients with high risk factors.

MATERIALS AND METHODS

Clinicopathological data of gastric cancer patients, who had undergone gastrectomy in high volume centers in Korea and China and were finally diagnosed with pT1bN0 and pT2N0 between 2006 and 2010, were analyzed retrospectively. Survival analyses stratified by risk factors and multivariable analyses were performed.

RESULTS

A total of 1509 patients were enrolled, with 41 (2.7%) patients receiving adjuvant chemotherapy after gastrectomy and 1468 (97.3%) patients undergoing surgery alone. The adjuvant chemotherapy group showed higher percentages of tumor with maximal diameter >3 cm (51.2% vs. 25.8%), poor differentiation (68.3% vs. 49.8%), and less harvested lymph nodes (17.1% vs. 5.2%) compared to the surgery alone group. The overall survival rates were 95.1% in the adjuvant chemotherapy group and 93.3% in the surgery alone group, without significant difference. In multivariable analysis, age was found to be an independent prognostic factor. However, there were no difference in the overall survival between patients with risk factors and those without risk factors, even in terms of age. Meanwhile, patients with more than two risk factors who received chemotherapy showed better survival trend, especially for pT2N0 patients, compared to the surgery alone group, although no significant differences were observed.

CONCLUSION

In pT1bN0 and pT2N0 patients, age was found to be an independent prognostic factor. However, adjuvant chemotherapy seemed to be unnecessary, while postoperative chemotherapy might offer survival benefits to pT2N0 patients with more than two risk factors.

Decision-making of adjuvant therapy in pT1N1M0 gastric cancer: Should radiotherapy be added to chemotherapy? A propensity score-matched analysis

Background: Early gastric cancer (EGC) with metastatic lymph nodes (mLNs) has a relatively higher recurrence rate and poorer prognosis than EGC without mLNs. However, the postoperative treatment directions of pT1N1M0 vary from different guidelines. This study attempted to confirm the value of postoperative treatments in pT1N1M0 GC patients.

Methods: Overall, 379 patients with pT1N1M0 GC following gastrectomy from 2000 to 2016 were selected from the Surveillance, Epidemiology, and End Results (SEER) database. Propensity score-matched (PSM) analysis was used to reduce bias. Overall survival was analyzed by Kaplan-Meier method and the log-rank test. Cox proportional hazards regression analyses were used to confirm the independent prognostic factors.

Results: Before matching, the results of survival analyses indicated that adjuvant chemotherapy (ACT) and chemoradiotherapy (ACRT) could significantly prolong the survival time of the cohort (P < 0.05). After PSM analysis, 136 patients remained and ACRT maintained significance in the survival analysis (P = 0.018). Furthermore, patients with well or moderately differentiated GC (HR = 0.226, P =0.018) or intestinal type GC (HR = 0.380, P = 0.040) achieved a significantly superior prognosis with ACRT, compared to patients receiving ACT.

Conclusion: The survival benefit of ACRT and ACT for pT1N1M0 GC patients following gastrectomy was confirmed in the SEER cohort. RT added to ACT might be recommended according to Lauren's classification and tumor grade in clinical decision making.

Is Additional Surgery Always Sufficient for Preventing Recurrence After Endoscopic Submucosal Dissection with Curability C-2 for Early Gastric Cancer?

BACKGROUND

When a lesion does not meet the curative criteria of endoscopic submucosal dissection (ESD) for early gastric cancer (EGC), referred to as non-curative resection or curability C-2 in the guidelines, an additional surgery is the standard therapy because of the risk of lymph node metastasis (LNM).

OBJECTIVE

This study aimed to identify high-risk patients for recurrence after additional surgery for curability C-2 ESD of EGC.

METHODS

This multicenter retrospective cohort study enrolled 1064 patients who underwent additional surgery after curability C-2 ESD for EGC. We evaluated the recurrence rate and the risk factors for recurrence after additional surgery in these patients.

RESULTS

The 5-year recurrence rate after additional surgery was 1.3%. Multivariate Cox analysis revealed that the independent risk factors for recurrence after additional surgery were LNM (hazard ratio [HR] 32.47; p < 0.001) and vascular invasion (HR 4.75; p = 0.014). Moreover, patients with both LNM and vascular invasion had a high rate of recurrence after additional surgery (24.6% in 5 years), with a high HR (119.32) compared with those with neither LNM nor vascular invasion. Among patients with no vascular invasion, a high rate of recurrence was observed in those with N2/N3 disease according to the American Joint Committee on Cancer TNM staging system (27.3% in 5 years), in contrast with no recurrence in those with N1 disease.

CONCLUSIONS

Patients with both LNM (N1-N3) and vascular invasion, as well as those with N2/N3 disease but no vascular invasion, would be candidates for adjuvant chemotherapy after additional surgery for curability C-2 ESD of EGC.

Stage-specific difference in timing and pattern of initial recurrence after curative surgery for gastric cancer

BACKGROUND

Gastric cancer (GC) follow-up schedule after curative surgery is universally recommended based on the pathologic stage, but their details, including intervals and modalities of surveillance have not yet been standardised. The aim of this study was to investigate the characteristics of GC recurrence by stage to establish optimal postoperative surveillance strategies.

METHODS

Medical information on 5095 patients with GC who underwent curative intent gastrectomy in our institution between January 1989 and December 2013 was reviewed retrospectively. Moreover, 656 patients who had recurrences after radical surgery were identified. Clinicopathologic characteristics, timing and pattern of recurrence, and survival data of these patients were analysed.

RESULTS

Among the 656 patients, 50 (7.6%), 123 (18.8%), and 483 (73.6%) had stages I, II, and III GC, respectively. The median times to initial recurrence in patients with stages I, II, and III GC were 23.5 months (interquartile range [IQR], 13.0-33.0 months), 13.0 months (IQR, 9.0-25.0 months), and 12.0 months (IQR, 7.0-21.0 months), respectively. In patients with stage I GC, more than half (58%) of them had distant organ metastasis; otherwise, peritoneal dissemination (39%) was the most common pattern in patients with stage III GC.

CONCLUSIONS

Despite the low incidence, the time of initial recurrence in stage I GC was longer than those in stage II and III GC. Moreover, the pattern of initial recurrence was also different according to the pathologic stage. Therefore, clinicians should consider stage-specific differences of recurrence in setting up surveillance strategies after curative surgery for GC patients.

Implication of lymph node staging in migration and different treatment strategies for stage T2N0M0 and T1N1M0 resected gastric cancer: a SEER population analysis

PURPOSE

The purpose of this study was to explore the differences between stage T2N0M0 and stage T1N1M0 gastric cancer (GC) and to identify the necessity of adjuvant treatment (AT) for these stages.

METHODS

Between years 2004 and 2015, 1971 stage IB GC patients who underwent radical surgery were recruited using the Surveillance, Epidemiology and End Results database. We conducted univariate/multivariate analyses, the propensity score matching and evaluated gastric cancer-specific survival (GCSS) and overall survival (OS) with the log-rank test.

RESULTS

T1N1M0 had a significantly worse survival than T2N0M0 in both GCSS and OS before and after the propensity score matching. Examined lymph nodes (ELN) ≤ 15 and T1N1M0 were independent risk factors for worse GCSS and OS in stage IB GC. The absence of adjuvant chemotherapy (CT) was an independent risk factor for worse GCSS and OS in T1N1M0 but not in T2N0M0. AT demonstrated similar GCSS and OS with surgery alone (SA) for T2N0M0 but better survival for T1N1M0. Compared to CT and adjuvant chemoradiotherapy (CRT) group, SA demonstrated significantly worse GCSS and OS for T1N1M0. There was no significant difference between CT and CRT in both T2N0M0 and T1N1M0 stages. T2N0M0 had a better survival than T1N1M0 in ELN ≤ 15 subgroup. However, similar survival was demonstrated in ELN > 15 subgroup.

CONCLUSIONS

T2N0M0 GC has a better survival rate than T1N1M0 GC when ELN are ≤ 15. Moreover, T2N0M0 GC may not benefit from AT. T1N1M0 GC requires CT but not adjuvant radiotherapy.

Implications of clinical research on adjuvant chemotherapy for gastric cancer: Where to go next?

Postoperative adjuvant chemotherapy (ACT) confers superior gastric cancer (GC) survival in the Eastern cohort. However, is the current standard of ACT already excessive, or is it still necessary to increase its intensity for specific subgroups? Tailored ACT strategies for GC depend on gradual exploration by clinical trials in selected patients. Thus, understanding the implications of previous and current research can help us respond wisely and design effective, rational trials, save medical resources and make better decisions in clinical practice. After reviewing and analyzing studies on ACT for GC patients undergoing curative resection, we found that research strategies for conducting “addition” ACT for specific stages of the disease have achieved great progress in making ACT more tailored and personalized in consideration of pathology stages. Furthermore, trials indicate that “addition” ACT strategies for GC patient subgroups based on histological characteristics might be helpful to move toward a more specific tailored and personalized management approach. Designing ACT research focused on different node statuses should also be conducted according to the biological specificity of lymph node (LN) metastasis. Therefore, future trials designed to determine tailored treatment based on histological and biological characteristics for specific subgroups are urgently needed and conducted as the theme of the 2019 American Society of Clinical Oncology (ASCO): Caring for Every Patient, Learning from Every Patient.

Adjuvant Therapy is Associated with Improved Survival in pT1N1 Gastric Cancer in a Heterogeneous Western Patient Population

BACKGROUND

Two recent South Korean studies showed adjuvant therapy (AT) was not associated with improved survival in pT1N1 gastric adenocarcinoma (GAC). We established the prognostic utility of lymph node status, determined the pattern of use of AT, and compared survival stratified by type of AT in pT1N1 GAC in a Western patient population.

METHODS

We identified patients with pT1N0 and pT1N1 GAC using the National Cancer Database from 2004 to 2012. Clinicopathologic variables, treatment regimens, and overall survival (OS) were compared.

RESULTS

We compared 4516 (86.6%) pT1N0 to 696 (13.4%) pT1N1 patients. pT1N1 tumors were larger (median size 2.5 vs. 1.8 cm, p < 0.001), more often poorly differentiated (56.2% vs. 39.6%, p < 0.001), and had higher median retrieved lymph nodes (RLN) (14 vs. 12, p < 0.001) compared with pT1N0. pT1N1 was associated with worse median overall survival (OS) (6.9 vs. 9.9 years for pT1N0, p < 0.001). pN1 was independently associated with worse OS (hazard ratio [HR] 2.17, 95% confidence interval [CI] 1.84-2.56). Increased RLN was associated with improved OS (HR 0.73, 95% CI 0.65-0.83). Among pT1N1 patients, 330 (47.4%) had observation (OBS), 77 (11.1%) received adjuvant chemotherapy (ACT), 68 (9.8%) received adjuvant radiation therapy (ART), and 221 (31.8%) received adjuvant chemoradiation therapy (ACRT). ACT and ACRT were independently associated with improved OS (HR 0.37, 95% CI 0.22-0.65 and HR 0.40, 95% CI 0.28-0.57).

CONCLUSIONS

pN1 was associated with worse survival and RLN ≥ 15 was associated with improved survival in pT1 GAC. ACT and ACRT were independently associated with improved survival in pT1N1 gastric cancer suggesting a valuable role in Western patients.