@dave56pa
The TP53 mutations found in cancers are almost always only in the cancer (aka "somatic mutations"), not in every cell in your body where they can be passed down to your children (aka "germline mutations"). Somatic TP53 mutations are extremely common in cancers, while germline TP53 mutations are very rare. The people who interpret the DNA sequence from your tumor can often tell if there's a likelihood of a germline mutations and if so would suggest that you see a genetic counselor.

One way you might be able to tell yourself is from the "variant allele fraction (VAF)" of the mutation, which should be on the report that shows the KRAS and TP53 mutations. Often the VAF of somatic mutations, which are only in the cancer, is between 5 and 40%. This is because the specimen usually has both cancer and normal cells in it, and the mutation is only in the cancer cells. A germline mutation will usually be present at very close to 50%, or sometimes higher. So if the TP53 and KRAS mutations VAFs are both 30%, the TP53 is almost certainly only in the cancer, and you don't need to worry about your kids. If the KRAS mutations is there at 10% and the TP53 mutation at 50%, then you should go see the genetic counselor.