When 40-year-old John Tang (an assumed name, for reasons of patient confidentiality) first came down with a fever, sore throat and enlarged lymph nodes on both sides of his neck - classic symptoms of an upper respiratory tract infection - his doctor prescribed antibiotics and sent Tang home to rest.
But Tang's fever persisted even after he popped the last pill. The swelling in his lymph nodes, which are bean-shaped collections of infection-fighting cells found throughout the body, didn't subside.
Tang's doctor then performed a standard investigative procedure for enlarged lymph nodes called fine needle aspiration. A slender needle was inserted into the enlarged lymph node to extract cellular material. This was used to determine whether a more insidious cause, such as tuberculosis or cancer, lay beneath. But Tang's test drew a blank.
For three weeks, his lymph nodes continued to enlarge while he faded in and out of fevers. Finally, doctors removed one of the lymph nodes for further tissue tests - known as a biopsy - and found lymphoma. This is a cancer of the lymphatic cells of the immune system.
In lymphoma, the lymphocytes - the white blood cells - become abnormal (cancerous). Instead of protecting him, part of Tang's immune system was now threatening to kill him. He was referred to Dr Raymond Liang, director of the Comprehensive Oncology Centre at the Hong Kong Sanatorium and Hospital.
The next challenge was to narrow down the type and extent of Tang's lymphoma to ensure an accurate prognosis and treatment plan. This was done through special tests, such as the monoclonal antibody test, which detects specific antigens (substances which trigger the production of antibodies).
PET - or positron emission tomography - scans were used to determine the affected lymph nodes more clearly, and a bone marrow biopsy was carried out to determine whether the cancer had affected Tang's bone marrow.
