How Effective Are Long Acting Injections In Managing Spread Of Tumor?

Respected Oncologist, We have found that my mother has tumors in Pancreas,it spread to liver and into some rib bones after we came to know she lost 10 kgs body weight.She has diabetics after full infection in Pancreas.We have done biopsy test it shows Pancreatic neuroendocrine tumor. When i asked oncologist,he told me that we can t do any surgery,radiotherapy and chemotherapy because tumors already spread into sensitive body parts.Finally he mentioned,we can try by long acting injection to control the spread and extend the life. We need a experts guidance before going into any kind of treatment.For that he asked me to do blood serum test -chromogranin A . 1.)What is Long active injection and do it has any side effects ? 2.)Is there any best treatment to safe my mother ?