Radiotherapy + Chemoimmunotherapy Followed by Surgery in Patients With Limited Metastatic Gastric or GEJ Cancer

Summary

The goal of this clinical trial is to evaluate the efficacy and safety of radiotherapy combined with chemotherapy and anti-PD-1 immunotherapy followed by surgery for the primary and metastatic lesions in patients with limited metastatic gastric or gastroesophageal junction adenocarcinoma. The main questions it aims to answer are: 1) If the multimodal treatment which includes anti-PD-1 immunotherapy and local therapies will improve the survival of this group of patients. 2) If the multimodal treatment which includes anti-PD-1 immunotherapy and local therapies can be performed safely in this group of patients.

Participants will receive short course hypofractionated radiotherapy (HFRT) for the primary lesion, HFRT or stereotactic body radiotherapy (SBRT) for metastatic lesions, combined with systemic chemotherapy and anti-PD-1 immunotherapy. For patients with HER2-positive cancer (defined as IHC 3+ or 2+/ISH+), trastuzumab is used along with chemotherapy and anti-PD-1 antibody. Then, surgical resections of primary and metastatic lesions are performed as much as possible. For patients who need a widely invasive surgical approach or are inoperable, local ablative therapies such as radiofrequency ablation (RFA) and microwave ablation (MVA) can be alternatives. For patients undergoing surgical resections, postoperative treatment includes chemotherapy, which is determined by the researcher, and PD-1 antibody, which will be maintained until one year after surgery.

Conditions

• Adenocarcinoma
• Stomach Neoplasm
• Gastroesophageal-junction Cancer
• Oligometastatic Disease
• Metastatic Cancer
• Metastatic Gastric Cancer
• Adenocarcinoma of the Stomach
• Gastroesophageal Junction Adenocarcinoma
• Metastatic Adenocarcinoma

Interventions

RADIATION

Radiotherapy targeted to the primary lesion

5 to 7 fractions of short course hypofractionated radiotherapy (HFRT) targeted to the primary lesion.

RADIATION

Radiotherapy targeted to the metastatic lesions

Hypofractionated radiotherapy (HFRT) or stereotactic body radiotherapy (SBRT) targeted to metastatic lesions. The target dose will be adjusted based on the lesion's site and diameter and organs at risk, with high-dose irradiation of 4-8 fractions. All metastatic lesions should be irradiated as much as possible, and partial lesion irradiation should be allowed when technically impractical.

BIOLOGICAL

Anti-PD-1 monoclonal antibody

The anti-PD-1 mAb is used on day 1 along with each cycle of chemotherapy. There are no restrictions on the choice of anti-PD-1 mAb. Patients can choose commonly used accessible monoclonal antibodies based on their personal preferences and financial status. The commonly used anti-PD-1 mAb usages are as follows: Nivolumab/Toripalimab 240mg solution intravenously once daily, Q2W. OR Nivolumab/Toripalimab 360mg solution intravenously once daily, Q3W; OR Pembrolizumab/Tislelizumab/Sintilimab/Camrelizumab, 200mg solution intravenously once daily, Q3W.

BIOLOGICAL

Trastuzumab

For patients with HER2-positive cancer (defined as IHC 3+ or 2+/ISH+), trastuzumab is used along with chemotherapy and anti-PD-1 antibody. The 3-weekly schedule of trastuzumab starts with a loading dose of trastuzumab of 8 mg/kg, followed by 6 mg/kg trastuzumab every 21 days.

DRUG

Chemotherapy

The investigator's choice of chemotherapy regimens included SOX, XELOX or FOLFOX. Their usages are as follows: SOX: S-1 twice a day, days 1-14, the dose of S-1 is accorded to body-surface area (BSA): patients with a BSA of less than 1.25 m2 receive 80 mg daily; those with a BSA of 1.25 m2 or more but less than 1.5 m2 receive 100 mg daily; and those with a BSA of 1.5 m2 or more receive 120 mg daily; and oxaliplatin 130 mg/m2, day 1, every 3 weeks; XELOX: Capecitabine 1000 mg/m2 twice a day, days 1-14 and oxaliplatin 130 mg/m2, day 1, every 3 weeks; FOLFOX: Leucovorin 400 mg/m2, day 1, fluorouracil 400 mg/m2, day 1 and 1200 mg/m2, days 1-2, and oxaliplatin 85 mg/m2, day 1, every 2 weeks.

PROCEDURE

R0 total/subtotal gastrectomy with D2 lymphadenectomy

For patients with a good response to preoperative treatment, surgical resection of primary and metastatic lesions is recommended. For primary lesions, gastrectomy with standard D2 lymphadenectomy is commonly used. The type of gastrectomy performed depends on the location and extent of the primary lesion. For GEJ or upper-third tumors, a 3 cm esophageal margin is recommended, and a total gastrectomy or esophagogastrectomy is performed. For middle-third tumors, the gastric margin is recommended to be more than 5 cm, and total gastrectomy is performed. For lower-third tumors, a 2 cm duodenal margin is recommended, and subtotal or total gastrectomy is performed. Billroth I or Roux-en-Y gastrojejunostomy is performed for distal gastrectomy patients. Roux-en-Y esophagojejunostomy is performed for patients receiving total gastrectomy.

PROCEDURE

Metastasectomy

For patients with a good response to preoperative treatment, surgical resection of primary and metastatic lesions is recommended. For metastatic lesions, the surgical procedure and resection range are determined by the surgeon.

PROCEDURE

Local ablative therapies

Local ablative therapies such as radiofrequency ablation (RFA) and microwave ablation (MVA) achieve high rates of complete tumor eradication of small metastases, and can be seen as alternatives if a widely invasive surgical approach is required or patient is inoperable.

Sponsors & Collaborators

• Fudan University

  lead OTHER

Study Design

Allocation

NA

Purpose

TREATMENT

Masking

NONE

Model

SINGLE_GROUP

Eligibility

Min Age

18 Years

Max Age

75 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2023-01-01

Primary Completion

2025-12-31

Completion

2027-12-31

Countries

• China

Study Locations