Advances in the treatment of gastric cancer

To provide an up-to-date review on the management of cancers of the stomach and esophagogastric junction (EGJ).

Microsatellite instable (MSI) high status in gastric cancer may portend a relatively good prognosis and indicate that adjuvant chemotherapy is of no added benefit to primary surgical management. In the preoperative treatment of HER2 (ErbB2)-positive EGJ adenocarcinoma with chemoradiotherapy, the addition of trastuzumab, a recombinant humanized mAb directed against the extracellular domain of Her2, failed to improve outcome over conventional chemoradiotherapy alone. Escalating the dose of radiation in combined chemoradiotherapy regimens did not improve survival over conventional dose radiotherapy in the nonoperative management of EGJ cancer. The use of proton vs. conventional external beam radiation therapy, although potentially less toxic, did not improve therapy outcome with preoperative or definitive chemoradiotherapy in EGJ cancer. In metastatic HER2-positive gastric cancer, after disease progression on trastuzumab, continuation of trastuzumab did not improve progression free or overall survival compared with second-line chemotherapy alone. However, in the setting or prior trastuzumab therapy in metastatic HER2-positive gastric cancer, the new agent trastuzumab deruxtecan achieved significant rates of response, progression free and overall survival compared with standard chemotherapy. After initial chemotherapy for metastatic esophagogastric cancer, maintenance therapy with the anti PDL-1 agent avelumab was no better than chemotherapy alone.

MSI high gastric cancer has a better prognosis and may not require adjuvant chemotherapy. Trastuzumab, added to preoperative chemoradiotherapy in HER2-positive esophageal adenocarcinoma, does not improve outcome. Dose escalation of radiotherapy in the nonoperative management of EGJ cancer does not improve local control or survival, and proton therapy may not achieve superior outcomes compared with external beam radiotherapy. In metastatic HER2-positive gastric cancer, continuing trastuzumab into second-line chemotherapy does not add benefit; however, the novel agent trastuzumab deruxtecan has substantial activity after prior trastuzumab-based therapy.