Discussion: I am a 39-year-old cancer patient, having recovered in my youth. I live in terrible fear and need supportive psychological treatment. My children and husband help me, but I am depressed.

The fear of cancer patients returning is natural and understandable. Depression (the fourth stage in the Kübler-Ross model of grief) is a stage you will find in most seriously ill patients with chronic diseases. I recommend you familiarize yourself with the Kubler-Ross model. Psychological treatments will help you get through mental crises. Still, the husband's and family's love and support are critical.
Regarding patients whose cancer broke out at a very young age, as you point out, it is necessary to emphasize the mental-energetic side. I recommend you read the article in the attached link. Cancer in young people often originates from unresolved traumas that reside in the subconscious, limiting access.

Link:
Kübler-Ross model | Explains the behavior of personal loss.
https://www.sf-healing.com/page/114 (Copy & Paste)