In mainland China, 70% of lung cancer cases were diagnosed in the final stage of the disease. The 5-year survival rate of these patients remains at less than 5%. Similarly, in Hong Kong, 80% of lung cancer cases were diagnosed in the later stages, making lung cancer one of the deadliest cancers in the Asia-pacific region. In the past decade, the overall 5-year survival rate of lung cancer has increased from 12% to 21% despite significant advancements in pharmaceuticals and medical technology. The survival rate of late stage lung cancer is less than 10%. Its high mortality rate is due to the fact that lung cancer symptoms do not show until the condition deteriorates, usually with no indications in the early stages.
As mentioned, symptoms of lung cancer typically only become more pronounced as the disease progresses, and greatly resemble those that are caused by other upper respiratory conditions, such as persistent coughing, voice hoarseness and fatigue. While it is true that tobacco smoking and drinking, especially from a young age, are responsible for the vast majority of lung cancer cases, many non-smokers and non-drinkers have been diagnosed with the condition each year. In other words, smoking and drinking patterns alone are not sufficient to explain lung cancer prevalence. Lung cancer is divided into two main types: non-small-cell lung cancer (NSCLC) and small-cell lung cancer (SCLC). SCLC is typically caused by smoking, and only represents fewer than 20% of all lung cancer cases. In Hong Kong, 90% of females diagnosed with SCLC have never smoked; whereas 30-40% of males diagnosed with SCLC have never smoked.
There is growing evidence to support that genetic mutations play critical roles in the development and progression of lung cancer. Those who are at risk of developing lung cancer can opt for lung cancer screenings, such as blood tests and biopsies, to test for possible gene mutations. Fortunately, novel treatment options are available for female non-smokers who have lung cancer as a result of EGFR gene mutations. Such treatment was found to have doubled progression-free survival rates in this patient cohort.
On the other hand, SCLC quickly grows and spreads to other parts of the body, including the lymph nodes. Recent research shows that SCLC patients who receive chemotherapy and immunotherapy can extend their overall survival period from two months to a year, compared to those who are treated with chemotherapy only.