First of all, to clarify, unresectable gastric cancer refers to progressive gastric cancer that is difficult to remove the lesion surgically by R0 at the time of initial diagnosis (i.e., no cancer cells are found to remain microscopically after resection) and will have tumor residual after surgery, including locally progressive gastric cancer that is difficult to resect and advanced gastric cancer with distant metastases. What treatments are available for these gastric cancers?
Systemic chemotherapy as the primary strategy
The main treatment regimen currently recommended by the National Comprehensive Cancer Network (NCCN) guidelines, the Japanese gastric cancer statute, and the European Society of Oncology guidelines is systemic chemotherapy based on fluorouracil, platinum, or paclitaxel. Current chemotherapy regimens proven to be effective in the treatment of gastric cancer include docetaxel + platinum + fluorouracil, platinum + fluorouracil, etc. Patients suitable for targeted therapy can also add trastuzumab (Trastuzumab, trade name Herceptin), apatinib, etc. to their chemotherapy regimen.
Conversion to resectable is also a direction
Gastric cancer may also be converted to resectable by giving systemic chemotherapy, radiotherapy, targeted drugs, and other treatments. If the tumor is considered to be in partial or complete remission after these treatments, and if the cancer has a chance of R0 resection, the surgeon will perform a radical gastrectomy (clearing to station 2 lymph nodes), usually followed by adjuvant chemotherapy based on pathology, which can ultimately extend the patient’s overall survival and improve quality of life. These treatments can ultimately extend the overall survival time and improve the quality of life.
There are “tricks” to deal with distant metastases
Some gastric cancers with distant metastases are usually inoperable, such as liver metastases, peritoneal metastases, and distant lymph node metastases. For these patients, doctors will develop individualized treatment plans based on the situation.
Liver metastases only 10% to 20% of liver metastases can undergo radical resection.
- Gastric cancer D2 radical resection after hepatic artery chemoembolization combined with systemic chemotherapy was given with a significantly longer median survival time of 6 months (from 8 months to 14 months) compared with chemotherapy alone.
- Gastric cancer D2 radical surgery with liver metastasectomy or radiofrequency ablation improved median survival (from 8.1 months to 17 months) and 3-year survival (from 0 to 31.7%) compared with chemotherapy alone.
Peritoneal metastases If the primary site is potentially resectable but has occult peritoneal metastases, i.e., positive peritoneal nodules or ascites shedding cells on abdominal exploration, gastric cancer reduction combined with intraoperative or postoperative peritoneal thermoperfusion chemotherapy plus systemic chemotherapy can result in a median survival time of up to 25 months.
Distant lymph node metastases For patients with metastatic abdominal para-aortic lymph nodes, the response rate with XELOX regimen chemotherapy [i.e., Capecitabine+Oxaliplatin] in combination with radical gastric cancer surgery can reach 85.1%, and chemotherapy Progression-free survival (from 5.6 months to 18.1 months) and overall survival (from 12.5 months to more than 58.7 months) were significantly longer for patients treated with combination surgery versus chemotherapy alone.
Palliative care for complications
Patients with comorbidities such as bleeding, obstruction, or perforation are often considered for palliative gastrectomy, short-circuit surgery (where the stomach is connected to the intestine by bypassing the obstructing lesion so that food is rerouted directly from the stomach to the intestine), or enteral nutrition tube placement, which can have a positive impact on improving symptoms, quality of life, and survival time.
In summary, chemotherapy is usually the primary treatment for inoperable gastric cancer, and depending on the circumstances, physicians may also consider radiotherapy, arterial chemoembolization, radiofrequency ablation, and palliative care. Treatment is not set in stone, and long-term survival of inoperable gastric cancer may be possible with individualized implementation of comprehensive treatment.