a new york kid with brain tumor heals after a trip to amazon forest

This is an American film from the late 80s or 90s. A kid who has brain tumor wants to visit the rainforests in Latin America as his last wish. He goes there with his mother. After coming back, he learns that his tumor is gone. In other words, he was somehow healed during this trip.

Note: I really need to find this movie and I would appreciate any hint. Thanks so much!