Welcome to the stage one seminoma club (or SOS as Paul54 sometimes refers to it). Very exclusive with an incredibly steep price to join. Seriously, welcome and sorry you had to find us.
Seminoma stage one is an utterly curable cancer with a survivor rate for compliant patients hugging the 100% line. Compliant means that you follow your treatment protocol for the prescribed period.
There is no survival rate difference for surveillance vs carboplatin vs radiation. Based on your info, the I/O alone has an 85% chance of having been curative. That means that if you do carbo, there is an 85% chance you do not need it. That being said, it is all about what makes you comfortable and lets you sleep at night and gets you past this cancer thing... getting it further, ad further in your rear view mirror!
Carbo is well documented to have no adverse effects, but the time frame for that documentation is short relative to radiation. The post treatment frequency of CT scans does drop if you do carbo, however I will caution that with new CT machines emitting lower doses of radiation and the advent of personalized scanning, the case against CT's and their radiation causing ill side effects is less and less relevant. It is well discussed in the forum and you can do a search on it.
I have given most of your questions a crack;
TWhat exactly did the actual report say about rete testis?he path report says:
pure seminoma, size of tumor 3.2/1.7/2 cm,
with rete testis invasion, no lymphovascular invasion is observed,
isolated aspects of Intratubular germ cell neoplasia,
spermatic cord margin is free of tumor (pT1)
1) Is this IA or IB or something else?
Chances of relapse after one dose 4-6%, after 2 doses it goes to 2-3%...2) My uro doctor (I haven't seen an oncologist until now) says I could do surveillance or 2 doses of carboplatin, but he recommends carboplatin just to be on the safe side.
What are the chances of a relapse for 1 dose, 2 doses or surveillance considering rete testis invasion?
Carbo does not generally efect fertility, but to be on the safe side, banking some sperm at least temporarily is a good idea.3) I am planning to start a family but I just found out that my fertility is bad. Does 1 dose/2 doses of carboplatin affect fertility? Is it just temporary or not? Are there any studies about that?
You really need to discuss with a fertility expert. Just how many you need is a function of how many viable swimmers and your spouses fertility and a bunch more factors. I will however repeat that carbo does not seem to endanger fertility.4) I banked some sperm and the lab results said that it could be only used for ICSI. I only have 3 vials. Should I bank more vials considering that one vial is used for one try?
If you are asking about carboplatin, then 6 to 8 weeks max post I/O6) What should be the time interval between I/O and treatment?
You have already had a baseline scan, the next one should be 4 months after the first.7) Does it make sense to do a PET CT scan now? Or maybe better to do it after treatment (if any)?