Active surveillance is a medical strategy used to monitor patients with certain conditions, particularly cancer. Instead of immediately starting treatment, doctors regularly check for changes in the patient's health through tests and examinations. This approach helps to avoid unnecessary treatments and their side effects when the disease is not progressing. This method is often employed for slow-growing tumors or early-stage diseases, where immediate intervention may not be necessary. By keeping a close watch, healthcare providers can decide the best time to initiate treatment if the condition worsens, ensuring that patients receive care tailored to their specific needs.