Commentary: Gastric Cancer Surgery Trials, September 2022

Surgical resection plays a critical role in the management of early-stage gastric cancer. Depending on the tumor stage and location, there are different surgical approaches. Complications associated with surgical resection can significantly affect quality of life and ability to receive subsequent treatment. With recent advances in minimally invasive approaches, laparoscopic resections are emerging as an attractive option for patients undergoing oncologic surgeries.

The KLASS-02 trial was a multicenter, randomized, controlled, noninferiority clinical trial, which enrolled 1050 patients with locally advanced gastric cancer. Of the enrolled patients, 974 patients underwent R0 resection either by laparoscopic (n = 492) or open (n = 482) distal gastrectomy. In the previous readout of this study with 3 years of follow-up, laparoscopic distal gastrectomy had noninferior oncologic outcomes compared with open surgery for locally advanced gastric cancer. Son and colleagues are now reporting 5-year follow-up results. Overall survival (OS; 88.9% vs 88.7%; P = .30) and relapse-free survival (79.5% vs 81.1%; P = .658) rates were similar in both surgical groups. The pattern of recurrences was similar between the two groups as well, with peroneal (42.1% of patients) and hematogenous (20.8%) being the most frequent ones. However, patients who underwent laparoscopic vs open distal gastrectomy had a significantly lower late complication rate (6.5% vs 11.0%; P = .01). This study demonstrates that laparoscopic distal gastrectomy is an appropriate alternative to open distal gastrectomy and should be offered to patients who are treated in centers with experience in performing these types of operations.

Peritoneal metastasis is a common site for the spread of gastric cancer. As such, the role of hyperthermic intraperitoneal chemotherapy (HIPEC) in the management of this disease has been explored in a number of studies. The effectiveness of prophylactic HIPEC during resection of early-stage gastric cancer remains unknown.

Shen and colleagues conducted a propensity score-matching analysis looking at the efficacy and safety of HIPEC in this setting. The study evaluated outcomes of 395 patients with locally advanced gastric cancer who underwent resection with (n = 146) or without HIPEC (n = 248). In the HIPEC group, OS compared favorably to the surgery-only group (69.9% vs 40.8%, P = .049) and 2-year relapse-free survival was higher with HIPEC (60.7% vs 31.6%, P = .049).

Previously, the CYTO-CHIP propensity score analysis study performed in France demonstrated that HIPEC in addition to cytoreductive surgery resulted in improved OS in patients with advanced gastric cancer and peritoneal metastasis compared to cytoreduction surgery alone.¹ However, with both of these reports, interpretation of the results carries inherent limitations that are associated with retrospective study design. Prior prospective studies, on the other hand, had mixed results. An ongoing phase 3 prospective study of D2 resection and HIPEC in locally advanced gastric carcinoma (GASTRICHIP) will hopefully provide a definitive answer regarding the benefit of HIPEC in early-stage gastric cancer management (NCT01882933). Ultimately, going forward, the role of HIPEC in early-stage disease will need to be examined in a prospective study with carefully selected patients, using the latest biomarkers and systemic therapies.

Mismatch repair protein deficient (dMMR) or microsatellite unstable gastric cancer (MSI-H) have distinct biologic behaviors and treatment responses. They are much more responsive to immune checkpoint inhibitors in the metastatic setting. In early-stage disease, exploratory analysis of patients with MSI-H tumors previously enrolled in the perioperative MAGIC trial, revealed that patients with MSI-H tumors had a better prognosis when treated with surgery alone, and they potentially experienced detrimental effects from chemotherapy.²

The GERCOR NEONIPIGA single-arm phase 2 study enrolled 32 patients with resectable dMMR/MSI-H gastric and gastroesophageal junction tumors.³ Patients were treated with 240-mg neoadjuvant nivolumab once every 2 weeks six times and 1-mg/kg ipilimumab once every 6 weeks twice, followed by surgery and 480-mg adjuvant nivolumab once every 4 weeks nine times. Twenty-nine patients underwent resection. All resections were with negative margins (R0). Pathologic complete response was seen in 17 (58.6%) of patients. As of the February 2022 data cutoff, with a median duration of follow-up of 14.9 months, 30 out of 31 patients with early-stage disease remained alive and without recurrence or progression (one evaluable patient had metastatic disease).

These results certainly support further investigation of immunotherapy use in this patient population. However, in the absence of prospective randomized data, the combination of fluorouracil, leucovorin, oxaliplatin, and docetaxel (FLOT) remains the standard of care in those who can tolerate it. For patients with MSI-H tumors who are not candidates for combination chemotherapy or whose tumors are progressing on chemotherapy, neoadjuvant immunotherapy is certainly a good option to consider.

Additional References

1. Bonnot P-E et al. Cytoreductive surgery with or without hyperthermic intraperitoneal chemotherapy for gastric cancer with peritoneal metastases (CYTO-CHIP study): A propensity score analysis. J Clin Oncol. 2019;37:2028-2040. Doi: 10.1200/JCO.18.01688

2. Smyth EC et al. Mismatch repair deficiency, microsatellite instability, and survival: An exploratory analysis of the Medical Research Council Adjuvant Gastric Infusional Chemotherapy (MAGIC) trial. JAMA Oncol. 2017;3:1197-1203. Doi: 10.1001/jamaoncol.2016.6762

3. André T et al. Neoadjuvant nivolumab plus ipilimumab and adjuvant nivolumab in localized deficient mismatch repair/microsatellite instability-high gastric or esophagogastric junction adenocarcinoma: The GERCOR NEONIPIGA phase II study. J Clin Oncol. 2022 (Aug 15. Doi: 10.1200/JCO.22.00686

Surgical resection plays a critical role in the management of early-stage gastric cancer. Depending on the tumor stage and location, there are different surgical approaches. Complications associated with surgical resection can significantly affect quality of life and ability to receive subsequent treatment. With recent advances in minimally invasive approaches, laparoscopic resections are emerging as an attractive option for patients undergoing oncologic surgeries.

The KLASS-02 trial was a multicenter, randomized, controlled, noninferiority clinical trial, which enrolled 1050 patients with locally advanced gastric cancer. Of the enrolled patients, 974 patients underwent R0 resection either by laparoscopic (n = 492) or open (n = 482) distal gastrectomy. In the previous readout of this study with 3 years of follow-up, laparoscopic distal gastrectomy had noninferior oncologic outcomes compared with open surgery for locally advanced gastric cancer. Son and colleagues are now reporting 5-year follow-up results. Overall survival (OS; 88.9% vs 88.7%; P = .30) and relapse-free survival (79.5% vs 81.1%; P = .658) rates were similar in both surgical groups. The pattern of recurrences was similar between the two groups as well, with peroneal (42.1% of patients) and hematogenous (20.8%) being the most frequent ones. However, patients who underwent laparoscopic vs open distal gastrectomy had a significantly lower late complication rate (6.5% vs 11.0%; P = .01). This study demonstrates that laparoscopic distal gastrectomy is an appropriate alternative to open distal gastrectomy and should be offered to patients who are treated in centers with experience in performing these types of operations.

Peritoneal metastasis is a common site for the spread of gastric cancer. As such, the role of hyperthermic intraperitoneal chemotherapy (HIPEC) in the management of this disease has been explored in a number of studies. The effectiveness of prophylactic HIPEC during resection of early-stage gastric cancer remains unknown.

Shen and colleagues conducted a propensity score-matching analysis looking at the efficacy and safety of HIPEC in this setting. The study evaluated outcomes of 395 patients with locally advanced gastric cancer who underwent resection with (n = 146) or without HIPEC (n = 248). In the HIPEC group, OS compared favorably to the surgery-only group (69.9% vs 40.8%, P = .049) and 2-year relapse-free survival was higher with HIPEC (60.7% vs 31.6%, P = .049).

Previously, the CYTO-CHIP propensity score analysis study performed in France demonstrated that HIPEC in addition to cytoreductive surgery resulted in improved OS in patients with advanced gastric cancer and peritoneal metastasis compared to cytoreduction surgery alone.¹ However, with both of these reports, interpretation of the results carries inherent limitations that are associated with retrospective study design. Prior prospective studies, on the other hand, had mixed results. An ongoing phase 3 prospective study of D2 resection and HIPEC in locally advanced gastric carcinoma (GASTRICHIP) will hopefully provide a definitive answer regarding the benefit of HIPEC in early-stage gastric cancer management (NCT01882933). Ultimately, going forward, the role of HIPEC in early-stage disease will need to be examined in a prospective study with carefully selected patients, using the latest biomarkers and systemic therapies.

Mismatch repair protein deficient (dMMR) or microsatellite unstable gastric cancer (MSI-H) have distinct biologic behaviors and treatment responses. They are much more responsive to immune checkpoint inhibitors in the metastatic setting. In early-stage disease, exploratory analysis of patients with MSI-H tumors previously enrolled in the perioperative MAGIC trial, revealed that patients with MSI-H tumors had a better prognosis when treated with surgery alone, and they potentially experienced detrimental effects from chemotherapy.²

The GERCOR NEONIPIGA single-arm phase 2 study enrolled 32 patients with resectable dMMR/MSI-H gastric and gastroesophageal junction tumors.³ Patients were treated with 240-mg neoadjuvant nivolumab once every 2 weeks six times and 1-mg/kg ipilimumab once every 6 weeks twice, followed by surgery and 480-mg adjuvant nivolumab once every 4 weeks nine times. Twenty-nine patients underwent resection. All resections were with negative margins (R0). Pathologic complete response was seen in 17 (58.6%) of patients. As of the February 2022 data cutoff, with a median duration of follow-up of 14.9 months, 30 out of 31 patients with early-stage disease remained alive and without recurrence or progression (one evaluable patient had metastatic disease).

These results certainly support further investigation of immunotherapy use in this patient population. However, in the absence of prospective randomized data, the combination of fluorouracil, leucovorin, oxaliplatin, and docetaxel (FLOT) remains the standard of care in those who can tolerate it. For patients with MSI-H tumors who are not candidates for combination chemotherapy or whose tumors are progressing on chemotherapy, neoadjuvant immunotherapy is certainly a good option to consider.

Additional References

1. Bonnot P-E et al. Cytoreductive surgery with or without hyperthermic intraperitoneal chemotherapy for gastric cancer with peritoneal metastases (CYTO-CHIP study): A propensity score analysis. J Clin Oncol. 2019;37:2028-2040. Doi: 10.1200/JCO.18.01688

2. Smyth EC et al. Mismatch repair deficiency, microsatellite instability, and survival: An exploratory analysis of the Medical Research Council Adjuvant Gastric Infusional Chemotherapy (MAGIC) trial. JAMA Oncol. 2017;3:1197-1203. Doi: 10.1001/jamaoncol.2016.6762

3. André T et al. Neoadjuvant nivolumab plus ipilimumab and adjuvant nivolumab in localized deficient mismatch repair/microsatellite instability-high gastric or esophagogastric junction adenocarcinoma: The GERCOR NEONIPIGA phase II study. J Clin Oncol. 2022 (Aug 15. Doi: 10.1200/JCO.22.00686

Surgical resection plays a critical role in the management of early-stage gastric cancer. Depending on the tumor stage and location, there are different surgical approaches. Complications associated with surgical resection can significantly affect quality of life and ability to receive subsequent treatment. With recent advances in minimally invasive approaches, laparoscopic resections are emerging as an attractive option for patients undergoing oncologic surgeries.

The KLASS-02 trial was a multicenter, randomized, controlled, noninferiority clinical trial, which enrolled 1050 patients with locally advanced gastric cancer. Of the enrolled patients, 974 patients underwent R0 resection either by laparoscopic (n = 492) or open (n = 482) distal gastrectomy. In the previous readout of this study with 3 years of follow-up, laparoscopic distal gastrectomy had noninferior oncologic outcomes compared with open surgery for locally advanced gastric cancer. Son and colleagues are now reporting 5-year follow-up results. Overall survival (OS; 88.9% vs 88.7%; P = .30) and relapse-free survival (79.5% vs 81.1%; P = .658) rates were similar in both surgical groups. The pattern of recurrences was similar between the two groups as well, with peroneal (42.1% of patients) and hematogenous (20.8%) being the most frequent ones. However, patients who underwent laparoscopic vs open distal gastrectomy had a significantly lower late complication rate (6.5% vs 11.0%; P = .01). This study demonstrates that laparoscopic distal gastrectomy is an appropriate alternative to open distal gastrectomy and should be offered to patients who are treated in centers with experience in performing these types of operations.

Peritoneal metastasis is a common site for the spread of gastric cancer. As such, the role of hyperthermic intraperitoneal chemotherapy (HIPEC) in the management of this disease has been explored in a number of studies. The effectiveness of prophylactic HIPEC during resection of early-stage gastric cancer remains unknown.

Shen and colleagues conducted a propensity score-matching analysis looking at the efficacy and safety of HIPEC in this setting. The study evaluated outcomes of 395 patients with locally advanced gastric cancer who underwent resection with (n = 146) or without HIPEC (n = 248). In the HIPEC group, OS compared favorably to the surgery-only group (69.9% vs 40.8%, P = .049) and 2-year relapse-free survival was higher with HIPEC (60.7% vs 31.6%, P = .049).

Previously, the CYTO-CHIP propensity score analysis study performed in France demonstrated that HIPEC in addition to cytoreductive surgery resulted in improved OS in patients with advanced gastric cancer and peritoneal metastasis compared to cytoreduction surgery alone.¹ However, with both of these reports, interpretation of the results carries inherent limitations that are associated with retrospective study design. Prior prospective studies, on the other hand, had mixed results. An ongoing phase 3 prospective study of D2 resection and HIPEC in locally advanced gastric carcinoma (GASTRICHIP) will hopefully provide a definitive answer regarding the benefit of HIPEC in early-stage gastric cancer management (NCT01882933). Ultimately, going forward, the role of HIPEC in early-stage disease will need to be examined in a prospective study with carefully selected patients, using the latest biomarkers and systemic therapies.

Mismatch repair protein deficient (dMMR) or microsatellite unstable gastric cancer (MSI-H) have distinct biologic behaviors and treatment responses. They are much more responsive to immune checkpoint inhibitors in the metastatic setting. In early-stage disease, exploratory analysis of patients with MSI-H tumors previously enrolled in the perioperative MAGIC trial, revealed that patients with MSI-H tumors had a better prognosis when treated with surgery alone, and they potentially experienced detrimental effects from chemotherapy.²

The GERCOR NEONIPIGA single-arm phase 2 study enrolled 32 patients with resectable dMMR/MSI-H gastric and gastroesophageal junction tumors.³ Patients were treated with 240-mg neoadjuvant nivolumab once every 2 weeks six times and 1-mg/kg ipilimumab once every 6 weeks twice, followed by surgery and 480-mg adjuvant nivolumab once every 4 weeks nine times. Twenty-nine patients underwent resection. All resections were with negative margins (R0). Pathologic complete response was seen in 17 (58.6%) of patients. As of the February 2022 data cutoff, with a median duration of follow-up of 14.9 months, 30 out of 31 patients with early-stage disease remained alive and without recurrence or progression (one evaluable patient had metastatic disease).

These results certainly support further investigation of immunotherapy use in this patient population. However, in the absence of prospective randomized data, the combination of fluorouracil, leucovorin, oxaliplatin, and docetaxel (FLOT) remains the standard of care in those who can tolerate it. For patients with MSI-H tumors who are not candidates for combination chemotherapy or whose tumors are progressing on chemotherapy, neoadjuvant immunotherapy is certainly a good option to consider.

Additional References

1. Bonnot P-E et al. Cytoreductive surgery with or without hyperthermic intraperitoneal chemotherapy for gastric cancer with peritoneal metastases (CYTO-CHIP study): A propensity score analysis. J Clin Oncol. 2019;37:2028-2040. Doi: 10.1200/JCO.18.01688

2. Smyth EC et al. Mismatch repair deficiency, microsatellite instability, and survival: An exploratory analysis of the Medical Research Council Adjuvant Gastric Infusional Chemotherapy (MAGIC) trial. JAMA Oncol. 2017;3:1197-1203. Doi: 10.1001/jamaoncol.2016.6762

3. André T et al. Neoadjuvant nivolumab plus ipilimumab and adjuvant nivolumab in localized deficient mismatch repair/microsatellite instability-high gastric or esophagogastric junction adenocarcinoma: The GERCOR NEONIPIGA phase II study. J Clin Oncol. 2022 (Aug 15. Doi: 10.1200/JCO.22.00686