Firstly, anal fistulas can become cancerous. Statistical data show that the probability of malignant transformation in anal fistulas is 1/1000, and such transformations are relatively rare in clinical practice. However, anal fistulas can change, but the timing of malignant transformation varies. Generally, the longer the duration of an anal fistula, the higher the chance of it becoming cancerous. The factors contributing to this transformation typically include chronic inflammation, long-term irritation, bacterial infection, and stimulation from medications, all of which can lead to cancerous changes.