Bright red drops

My dog is a stray adopted off the streets six months ago, we had seen him around for atleast five years before that. For the last couple of weeks we noticed bright red drops of blood on the floor, which we localised as coming from his penis. His urine was always clear dark yellow, and he did not seem to be in any pain when passing urine.Today a vet. examined him and showed us a bilobate, irregular, cauliflower growth at the base of his penis, which bled freely when touched. He diagnosed it as cancer. He has advised 3 cycles of Vincristine at 21 day intervals.
What kind of cancer could it be? Sarcoma, adenoma, carcinaoma etc? Will it respond to single drug regimen of chemotherapy? His mucosa is still a healthy pink, he has a good appetite, and is active.
Please help, we're at a los, and our son is devastated.

[utahmomma]

You might want to post this to the "ask a vet" area of the forum.  She's a wonderful DVM and could give you a lot more information about penile cancer than we could.

I am so sorry for this diagnosis.  Please give your son and the dog a hug from me and my furbabies!!