Cancers

Neoplastic diseases
Neoplasms
Tumours
Cancerous growths
Sarcomas
Carcinoma in sita
Cancer

Nature

A tumour, or neoplasm, is a tissue growth with no physiological function. The first sign of tumour growth in a tissue is the appearance of a small number of cells which multiply with uncontrolled division and lose lose their capacity for differentiation. The tumour enlarges solely as a result of multiplication of its own cells. Tumour growth proceeds through stages of disorderly increase in the number of cells, focal growth, benign growth and malignant growth; the stages immediately preceding malignancy are called precancerous.

Incidence

Cancers represent a significant global health challenge, with the World Health Organization estimating that there were approximately 19.3 million new cancer cases and nearly 10 million cancer-related deaths worldwide in 2020. The incidence of cancer varies by region, with higher rates observed in developed countries due to factors such as lifestyle, environmental exposures, and access to healthcare. Notably, breast, lung, and colorectal cancers are among the most commonly diagnosed types, with the highest incidence rates found in North America and Europe.
In 2020, the United States reported over 1.8 million new cancer cases, with lung cancer being the leading cause of cancer death. The American Cancer Society highlighted that in 2020 alone, approximately 228,820 new cases of lung cancer were diagnosed, underscoring the ongoing impact of this disease in urban areas like New York City, where air pollution and smoking rates contribute to higher incidence levels.

Claim

Cancer is a disease of the genome, which means it’s characterised and caused by changes in our genes that can drive a healthy cell to mutate into a cancerous one. Cancer remains difficult to treat because each cancer is different, even within the same cancer type, such as breast or bowel. Each tumour has a genetic code that makes it unique, but there are also genetic differences within the tumours themselves. And tumours can evolve over time to become resistant to treatment.

Counter-claim

Up to 90% of cancer is preventable. "Environmental or nutritional factors probably account for up to 90% of human cancers. These factors include smoking; diet; and exposure to sunlight, chemicals, and drugs. Genetic, viral, and radiation factors may cause the rest." (The Merck Manual, 17th edition, pp. 2591-2592)