Sorry for the super late reply, you might not even need any more...
But I'd say that it's not wrong to keep it from them. How could it really? If you're sick and feel like telling someone will interfere in your well being, how could that be the wrong thing to do? This comes down to the question whether you should take your own needs before others, and in a situation like that, I'd sat you HAVE to think about yourself first. Human being's number one priority is survival, and if your survival hangs on not telling your parents that you are sick, then that's the case.

Especially since it becomes both physically and mentally challenging for your body when dealing with such a disease.

I don't think you would owe your parents something like that. It's your life, and sure, they "gave" you that life. But that doesn't mean that you have to pay back in any way. It's not your duty to carry out your parents wishes and I really do think that you have to only think about yourself in a situation like that.

Don't know if this helped or if you'll even see this.
Hope you're doing good. <3

From what I learned in school, cancer patients tell their parents (if they are still alive) about their condition for emotional support. Other reasons are from them to get themselves screened (coz some cancers are hereditary), or to warn them of future deterioration or recurrence. About your question, I'm sure parents will always go bat crazy if their child would hide something like that but in the long run, it's always better to be honest. It's a way of protecting yourself and your family. The feeling of being upset will soon fade but the guilt of keeping a secret will haunt you.

No, you are not wrong. You just have to make them sit, with you telling the truths. Yeahh, some might think ((esp your parents)) that you are selfish but at least you are being responsible to take care of your health well, followed all prescripted treatments and chemo's.

Yup, your parents will blow your head up, being mad and all that but it'll not last long because as much as you mad or hate someone that dearly to you, you'll find yourself loving and care them more : )

I'm having a little problem with figuring out what "their reaction affecting my recovery" means because I believe it's pretty important.

So I'm gonna take two different approaches here based on what that sentence means. If you're saying your parents might be abusive and stop you from getting certain treatments because they don't believe in it or don't want to spend the money or anything in the like - anything that would stop your treatment, then no, you're not in the wrong for not telling them.
Then their disappointment in you not telling them most likely manipulative as well. (But in that case I wouldn't have expected them to be happy I was alive either, tbh)

If that full sentence means that you keep it from them because you're scared their health will deteriorate and they will have a lot more concerns and you don't want to burden them with the news of your disease, then yes, you're wrong for not telling them. Because they will most likely feel guilty they couldn't help you through your hardships and your disease and you will put them in a dilemma that will have them considering whether or not they're bad parents since you kept something as important as this from them.

So - it fully depends on what that sentence means. ^^

I think you should have told your parents, but there's a specific way to do it so they don't worry too much.

You sit them down and say, "There's something I want to tell you. But before I do, I need you to know that I've been very responsible with what's happening and everything is under control."

Build it up and calm them down before saying, "I've got cancer." Letting your family know what's going on with you is important, and if they keep bugging you about it, you can tell them to stop, it's okay to do that, it's perfectly fine :) <3

I don't know anyone that wouldn't tell their parents though, that seems a little unrealistic with me, UNLESS, the relationship with that person's family is terrible, like actually they-don't-give-a- about anything in your life and suddenly breath down your neck for beneficial reasons terrible.

That's my take on that!

It's not wrong actually because you choose not to tell them because you worried about them , knowing that they will be sad...but it's wrong too not to tell them because we are family. Family should help each other.

Ah this is such a difficult question
Well imo both parties are simultaneously right and wrong
The person shouldn't have kept such a massive secret from their nearest and dearest but was doing it with good intentions
The parents should be happy their child is alive but how would they have felt if their child's condition deteriorated?
Honestly neither party is completely right or wrong but id probably side with the child bc they never intended any harm