Case in point, Cuba's lung cancer vaccine[1]. Which a company has brought to the U.S. as CIMAvax-EGF[2].
[1]: https://www.usatoday.com/story/news/world/2018/01/09/cuba-ha...
[1]: https://www.usatoday.com/story/news/world/2018/01/09/cuba-ha...
Not 100% sure, because I've only heard about vaccines in preventative contexts before, but based on this description my guess would be that "anything that tells your immune system to Do Stuff" counts as a vaccine. Versus something like Herceptin, which also treats cancer, just with ready-made antibodies that were grown in a lab.
English is not my native tongue so I have some problem to parse your sentence. I prefer the writing in the publication cited above [0] even if it's probably the same meaning:
"CIMAvax-EGF is a therapeutic cancer vaccine composed of human recombinant EGF"
[0] https://aacrjournals.org/clincancerres/article/22/15/3782/79...
Here's the sentence restructured:
... vaccine refers to anything that induces an immune response against a pathogen or disease. Here is how that definition applies in this case: the vaccine causes the immune system to produce anti-EGFR antibodies.