Optimal treatment of patients with stage II – III gastric cancer often requires more than one therapeutic approach. Thus, it is important for patients to be treated at a medical center that can offer multi-modality treatment involving medical oncologists, radiation oncologists, surgeons, gastroenterologists and nutritionists.
Multi-modality treatment with surgery, chemotherapy and/or radiation is the primary treatment for Stage II – III gastric cancer. In general, patients with cancer that has spread to the lymph nodes have a worse outcome than patients whose cancer has not spread to the lymph nodes.
Chemotherapy and/or radiation therapy without surgery is usually reserved for patients who are not able or do not wish to undergo major surgery.
Stage II gastric cancer involves deeper layers of the stomach and/or nearby lymph nodes.
Stage III gastric cancer has spread to structures adjacent to the stomach and/or to regional lymph nodes. Stage III gastric cancer can be further divided into stage IIIA and stage IIB.
- Stage IIIA gastric cancer invades the muscle of the wall of the stomach and 7 or more lymph nodes, the next-to-the-last layer of the stomach and 3-6 lymph nodes, or the outermost layer of the stomach (the serosa) and 1-2 lymph nodes.
- Stage IIIB gastric cancer invades the next-to-the-last layer of the stomach and 7 or more lymph nodes, the outermost layer of the stomach and 3-6 lymph nodes, or adjacent structures and few (1-2) or no lymph nodes.
Surgery as Primary Treatment
Depending a patient’s circumstances, surgery may be performed with the goal of curing gastric cancer or to relieve symptoms caused by the cancer. Surgery may involve removal of all or part of the stomach, and typically includes removal of several lymph nodes as well.
Surgery is often combined with other approaches to treatment such as chemotherapy. Some patients receive chemotherapy both before and after surgery. For patients who don’t receive chemotherapy prior to surgery, chemotherapy may be given in combination with radiation therapy after surgery.
In some cases, the patient may be too ill to undergo surgery or the cancer may be too extensive to allow surgery, and the patient will be offered non-surgical approaches to treatment.
Neoadjuvant Therapy (Treatment before Surgery)
Some patients may receive treatment with chemotherapy (with or without radiation therapy) prior to surgery. This treatment can help to reduce the extent of cancer, making it easier to remove the cancer during surgery.
Adjuvant Therapy (Treatment after Surgery)
The goal of additional treatment after surgery is to reduce the risk of cancer recurrence by eliminating any areas of cancer that may remain in the body. Adjuvant (post-surgery) therapy for Stage III gastric cancer typically involves chemotherapy alone or in combination with radiation therapy. The use of systemic adjuvant therapy appears to improve overall survival modestly.1
Precision Cancer Medicines
All patients with advanced gastric cancer should undergo genomic biomarker testing for HER2 and other targets in order to determine if they can benefit from treatment with a precision cancer medicine.
Precision cancer medicine utilizes molecular diagnostic testing, including DNA sequencing, to identify cancer-driving abnormalities in a cancer’s genome. Once a genetic abnormality is identified, a specific targeted therapy can be used to attack a specific mutation or other cancer-related change in the DNA programming of the cancer cells. Precision cancer medicine uses targeted drugs and immunotherapies engineered to directly attack gastric cancer cells with specific abnormalities, leaving normal cells largely unharmed.
Roughly 20% of patients with gastric cancer have cancer that over expresses (makes too much of) this protein; these cancers are referred to as HER2-positive. For patients with HER2-positive gastric cancer, treatment with Herceptin can improve overall survival.2
Chemotherapy and Radiation Therapy as Primary Treatment
If the cancer cannot be surgically removed or the patient is medically unable to undergo surgery, treatment of Stage III gastric cancer may involve a combination of chemotherapy and radiation therapy. It appears that the combination of chemotherapy and radiation therapy has substantial activity for the local control of advanced gastric cancer.
1 Paoletti X, Oba K, Burzykowski T, et al. Benefit of Adjuvant Chemotherapy for Resectable Gastric Cancer: A meta-analysis. JAMA. 2010;303(17):1729-1737.
2 Bang Y-J, Van Cutsem E, Feyereislova A et al. Trastuzumab in combination with chemotherapy versus chemotherapy alone for treatment of HER2-positive advanced gastric or gastro-oesophageal junction cancer (ToGA): a phase 3, open-label, randomised controlled trial. Lancet. 2010; 376:687-697.