Need some help and information

Hello friends,

My father is 73 years old and according to his tests, unfortunately he has got stomach cancer, I wanted to share the results with you and use your experiences.

First of all dr took an endoscopy and the result was: suspicious malignant tumor, then he sent the specimen to laboratory, the result was

C 16/3

M= 8140/3

After pathology results showed up dr sent my dad to CT scan for checking other parts of body in terms of metastasis.  Fortunately the answer was negative and other part of the body don’t integrate with cancer. in below you can see the CT scan result, please share your experience and knowledge if you had same condition like my father. I have read tons of articles and I’m confused and worry now

Infiltrative mass along gastric lesser curvature from cardia to the antrum without local periluminal vascular invasion associated with multiple enlarged lymph nodes along gastric lesser curve, para aortic region & mesenteric root

 Other part of the body like kidney, liver, bladder abdominal wall etc. are normal and as I said metastasis is negative

According to results, cancer is in which stage?

What kind of treatment dr will order

I will be appreciate if you share your experiences