Troopers cancer donation

Trooper was diagnosed in May with lymphoma and went threw first weekly then bi weekly treatments for 6 months at New England Veterinary Oncology Group in Waltham Ma. He responded very well to the costly treatment, he now has been going for monthly check ups. This has been a very high cost to our Family and I as I myself have Sarcoidosis and work in a seasonal business when possible. All profits have gone to Troopers medical expenses, he has been worth every penny! Trooper was so excited Christmas morning to get so many presents he was tap dancing. He brings us so much joy being the silly boy that he is. We rescued him from Knoxville TN. He is years only five years old. The cost of the first treatment made us make many sacrifices. Birthday and anniversary presents were all made up of Troopers picture and everyone was happy with our healthy dog. Well I felt guilty and tried to make up for it on Christmas and now two days after Christmas I found a lump while patting him on the couch. I immediately called NEVOG with this news and am bringing Trooper in tomorrow morning to see what is next step in treating him should this lump be bad news? I try to prepare for the worst and hope for the best. Should it be bad news I currently have no funds left to treat him at this time. I am not trying to get back the more than $6,000.00 that I have already spent this year on him. I just want to keep our family member around a few more years. He is a very good dog and just likes to play with every animal he meets. Any help would be greatly appreciated!