The respiratory system is a biological system that consists of many organs to help the body take in oxygen and expel carbon dioxide (respiration). Lungs are essential respiratory organs that facilitate respiration via inhalation and exhalation. Lungs are susceptible to both infectious and non-infectious diseases, including Tuberculosis (TB) and lung cancer. In comparing the two diseases, they have a few similarities regarding symptoms and diagnosis; however, they have dissimilar causes and treatments. In a real-life context, both have ethical issues pertaining to human rights.

Medical Overview

Lung cancer is a non-bacterial induced, aggressive, and metastatic cancer mainly caused by cigarette smoking; exposure to carcinogens such as pollution, asbestos, and chemicals; and genetic inheritance. Most lung cancer begins in the cells lining the bronchi and parts of the lung such as the bronchioles10. Inhaling carcinogens, such as cigarette smoke, instigate changes in cells’ genes, causing them to grow faster. Over time, abnormal cells will acquire further mutations, causing them to progress into cancerous cells and form a malignant tumor in the lungs. Cancer cells will damage lung tissues. Malignant lung tumors grow rapidly and may block the airway, making it difficult to breathe. Common symptoms of lung cancer include coughs, fatigue, and chest pain. In contrast, TB is a bacterial-induced, infectious disease caused by mycobacterium tuberculosis (Mtb)10 . Unlike lung cancer, TB is a non-hereditary, air-borne disease. When people with TB coughs6or speaks, they release TB bacterium-carrying air droplets. When others inhale the TB infected air, the bacterium will enter their body. A strong immune system can prevent the bacteria from becoming active; in this case, the person will have latent TB11. If a person is immunosuppressed, such as those with HIV, the TB bacteria is likely to become active and lodge in the lungs where it will grow and multiply, causing pulmonary TB12. A person is only contagious if they have active TB bacteria in their body. Similar to lung cancer, TB causes coughing, fatigue, and chest pain13 . TB can spread to other parts of the body (i.e. bones and brain). When lung tissues are affected by TB bacteria, it becomes hard, making oxygen exchange difficult or impossible. The cells that make up lung tissues begin to die, leading to lung tissue deterioration. This allows the bacteria to spread through the destructed tissue by gaining access to blood vessels that allow it to travel through the bloodstream and be disseminated. Likewise, lung cancer can spread when malignant cells break away from the primary tumor in the lungs, travel through the bloodstream or lymph stem, and grow a secondary tumor elsewhere. Individuals at high risk for getting lung cancer or TB are recommended to undergo screening tests. The most common screening for lung cancer is the CT scan, where cancerous regions will appear as lesions – small, abnormal areas – in the lungs. CT scan results help locate the tumor, reducing the need for exploratory surgeries. A popular screening test for TB is the Mantoux skin test, which involves injecting a purified protein derivative of Mtb into the surface of the forearm1. Within 48-72 hours of injection, the diameter of the indurated area is measured; if the induration is greater than 6mm, the test is considered TB-positive. Immunodeficiencies (ex. HIV) and vaccinations (ex. Bacillus Calmette–Guérin vaccine: BCG) can generate false-positive results. To rule out TB, X-Rays may be used for further diagnosis.


Both diseases can be diagnosed with X-Ray and sputum cytology. On X-Rays, the two diseases’ appearances are different; lung cancer appears as visible, individual masses/nodules2 while TB appears as connected, light spots3. X-Rays provide accurate diagnosis by using color contrast to generate a comprehensive image of the lungs. A disadvantage of X-Ray is radiation exposure which can cause cell mutations that may lead to cancer. Sputum cytology involves examining samples of sputum under the microscope for lung cancer cells or TB bacterium. Sputum cytology is useful for staging lung cancer and for confirming TB diagnosis done by X-Ray, where the disease may resemble other respiratory diseases.


If untreated, both diseases can be fatal. TB is a rarely surgical disease mainly treated with antibiotics. When used correctly, the medications are highly successful. Incorrect use of antibiotics can cause multi-drug resistant TB (MDR-TB), where the bacteria becomes resistant towards front-line medications. Extensively drug resistant TB (XDR-TB), where TB bacteria develops resistance against more antibiotics, can develop. Both MDR-TB and XDR-TB are difficult and expensive to treat. In contrast, because lung cancer is non-bacteria induced, antibiotics are not common treatment options. One treatment method is to surgically remove the tumor and margin tissues. The surgery has various risks, including excessive bleeding and wound infection. The survival rate of lung cancer is lower than that of TB. 52% of lung cancer patients live over 5 years after diagnosis4


To prevent TB, some countries (ex. China) offer BCG vaccine; however the vaccine’s effectiveness is questioned, thus countries like Canada do not offer it. Although there are no sure way to prevent lung cancer, stop smoking can reduce risk of getting it.

Ethical review

There are various ethical arguments surrounding lung cancer and TB. TB is a disease of poverty and inequality where access to treatment services is associated with people’s inability to realize their human rights7. Some countries do not offer free TB treatment, violating their obligation to provide accessible healthcare treatment. As written in Article 25 of the Universal Declaration of Human Rights, the Human Right to Health grants everyone the right to the highest attainable level of health and to access essential medicines”5. Countries with high numbers of TB patients are the ones who do not offer free TB care, implying the relationship between treatment cost and TB. A similar ethical issue regarding human rights arises with lung cancer. In Canada, smokers are required to pay up to 40%-100% higher insurance fees8. Although the implementation was intended to be a monetary enticement to stop smoking, financially enticing smokers to quit is an unjustified, paternalistic interference with personal autonomy as smokers should be allowed to make lifestyle choices free from coercion of insurers9 At the end, smokers may opt-out of buying health insurance due to the increased fees for smokers; this can be detrimental to their overall well-being.

In conclusion, both lung cancer and TB harm the respiratory system and impact people’s health. By knowing the causes and symptoms for the diseases, patients can obtain early diagnosis and proper treatment. In treating and preventing lung cancer and TB, monetary factors should be balanced with basic human rights. Easy and immediate access to health care is essential for a positive prognosis and successful disease management.