Preclinical studies at our institution, using a genetic mouse model of gastric cancer, strongly suggest that innervation of the stomach wall is required not only for the development, but also for the progression of gastric cancer, and that denervation of the stomach either by vagotomy or by injection of botulinum toxin (Botox®) in the stomach wall may represent an effective therapeutic intervention. New treatment options for inoperable cancer in the stomach are urgently needed, and local treatment with botulinum toxin seems to be an attractive possibility. In this pilot study Botox injections will be given by gastroscopy in both the tumor and the surrounding stomach wall. The purpose of the study is to obtain data needed to calculate sample size in a larger controlled trial.

Inclusion criteria:

Patients with verified gastric adenocarcinoma but found non-resectable or inoperable after evaluation in the appropriate multidisciplinary team at St.Olav Hospital. Trondheim University Hospital. The inclusion criteria for such patients are:

1. Patients who have received 1.line and 2. line chemotherapy but no longer respond to such therapy.
2. Patients who, due to toxicity of chemotherapy, cannot be offered such treatment.
3. Patients who, after meticulous information about chemotherapy, still do not want such treatment.
4. Patients with performance status (ECOG) 0-2.

Exclusion criteria:

1. Known allergy to any of the components in Botox®
2. Known peripheral motor neuropathy disease ( for example: Amyotrophic Lateral Sclerosis, ALS), or subclinical or clinical deficiency of neuromuscular transmission (for example: Myasthenia Gravis or Eaton-Lambert's Syndrome).
3. Pregnant or lactating women.
4. Another cancer disease that is not under control.
5. Another concomitant treatment for cancer.
6. Serious mental illness.
7. Performance status (ECOG) 3-4.