This chapter presents a glimpse on oncology description of disease related to pathology, laboratory, radiology, and pharmacology. Hodgkin’s disease is a malignancy of lymphatic tissue that primarily affects the lymph nodes but may also involve the spleen, gastrointestinal tract, liver, or bone marrow. Leukemia is a malignant disease of the blood-forming organs (spleen, lymphatic system, and bone marrow). Cytology examination means the study of cells, their origin, structure, and function. There are two major types of cytological studies; aspiration biopsy and exfoliative cytology. Ionizing radiation is used in cancer therapy in an attempt to destroy malignant cells. The application of the radiation may be either internal or external. Alkylataing agents are variety of drugs used in chemotherapy that destroy portions of the DNA molecule.