Source: The Great Interpretation of Dreams (Ibn Sirin)
(By analogy with malignant diseases) Cancer in a dream may indicate severe worry, a malignancy in religion or body, or a hidden enemy consuming the dreamer.
Source: Perfuming Humanity in the Expression of Dreams (Al-Nabulsi)
(By analogy) It may indicate unlawful money that corrupts its owner's life, or great strife, or long-lasting sorrow.
Source: Signs in the Science of Expressions (Ibn Shaheen)
(By analogy) It is interpreted as worry, grief, and illness. Recovery from it indicates the end of worry and repentance.