Cancer was relatively rare in the early 1900s compared to its prevalence in modern times. There are several reasons for this. First, the average life expectancy was significantly lower in the early 1900s, and cancer is more commonly diagnosed in older individuals. Additionally, medical knowledge and technology were not as advanced as they are today, so the detection and diagnosis of cancer were less accurate and widespread. Furthermore, certain risk factors for cancer, such as tobacco use and exposure to environmental toxins, were not as prevalent in earlier times.
It's important to note that although cancer was less commonly diagnosed in the early 1900s, this does not mean that cancer did not exist or that people did not suffer from it. Cancer has been present throughout human history, but its understanding, detection, and treatment have improved significantly over time. As our understanding of cancer has deepened and medical advancements have been made, the diagnosis and reporting of cancer cases have increased.