After your cancer diagnosis, you put your chin down and plowed through the task at hand — beating it. But you didn’t necessarily expect to be smacked with another huge challenge soon after: survivor’s guilt.

This psychological phenomenon, which includes strong, persistent feelings of sadness and remorse, is an unwelcome intrusion at the end of cancer treatment — a time that should, by all accounts, be joyful. And it doesn’t just include guilt itself, but also an overwhelming sense of distress, helplessness, and injustice. But the tension between trauma and relief is exactly what poses difficulty to scores of survivors who’d hoped to be free of cancer’s consequences, Harvard experts say.