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Cancer 101: What You Need to Know

cancer cells

For centuries, the story of cancer was one of limited options, but today, we are rewriting that narrative.1 Researchers are working tirelessly to improve outcomes for the $18 million people in the U.S. living with cancer as of 2022, turning the tide toward a future defined by survival and long-term health.2 

Here’s an overview of what cancer is, why it’s so hard to treat, and how research is transforming our understanding of it, accelerating treatment progress and improving patients’ lives. 

What is cancer, and how does it develop? 

The cells in our bodies grow, divide, and eventually die in a controlled process. Normally, the body destroys cells with damaged DNA before they can become cancerous. 

Cancer develops when certain cells grow uncontrollably, invade surrounding tissue, and spread to other parts of the body. Cancer is triggered by changes to our DNA, such as from: 

  • Lifestyle and environment: Often, these include factors we can influence, such as smoking, alcohol, and UV ray exposure. Poor diet and obesity also contribute by causing internal stress that damages cells.
  • Biological aging: As we age, our cells divide billions of times. Over time, the body naturally makes errors in its DNA that can lead to cancer.
  • Inherited genetics: Mutations may be passed down from parents. Although these don’t always cause cancer, they may increase the risk of cancer development.  

Why hasn’t cancer been cured yet? 

People often ask: Why is a cure so elusive? The answer lies in cancer’s incredible diversity. Not only are there more than 200 distinct types, but each case also arises from a unique combination of factors.3 While many cancers are linked to lifestyle, environment, and inherited risks, others are simply the result of random DNA copying errors that occur naturally as our cells divide.4  These genetic triggers do more than just initiate the disease; they create the potential for cellular evolution. While some cancers remain stable and highly treatable, others use this genetic flexibility to adapt, potentially developing the specific resistances that make them difficult to target. 

So instead of focusing on a single cure, we are focused on mastering this complexity to find precise ways to treat and control cancer, turning it into a manageable condition for everyone. 

We are already seeing the impact of this approach in real-time. 

Thanks to advances in early detection and treatment, some cancers—such as breast cancer, prostate cancer, and colon cancer—are now often highly treatable, if caught early. Because of this progress, cancer statistics are improving. For instance, the likelihood of dying from cancer in the U.S. has plummeted by 33% since the early 1990s.5 

What are the challenges to cancer research and treatment? 

Despite significant progress in understanding and treating cancer, researchers and doctors face several major challenges: 

  1. Finding treatment that’s effective for everyone: No two patients are identical, even when they have the same cancer diagnosis. Understanding why one treatment works for one patient but not another is one of the greatest hurdles in cancer care.
  2. Making care accessible: It’s critical to develop easy-to-provide, relatively low-tech, and inexpensive cancer prevention, screening, and diagnostic tests and treatments, especially for underserved communities. Early detection and treatment can improve patient outcomes, yet access remains inconsistent.
  3. Funding limitations: A major cancer research challenge is the shortage of funding. The National Cancer Institute, the largest funder of cancer research in the U.S., funds less than 10% of grant applications they receive.6 This can discourage early-career investigators applying for federal grants or even being qualified to receive them. 

To help address these challenges, Conquer Cancer®, the ASCO Foundation, supports researchers early in their careers. This support enables them to explore bold, transformative ideas that have the potential to improve cancer prevention, diagnosis, and care in the future. 

How do cancers differ in terms of development and treatment? 

Cancer causes and treatments differ greatly depending on the type of disease. The following examples of common cancers illustrate this variation:  

Breast cancer: Risk factors include being a woman and inheriting certain genetic mutations, specifically pathogenic variants of the BRCA1 and BRCA2 genes. Treatment options include surgery, radiation, chemotherapy, targeted therapy, and/or hormonal therapy.7 

Colon cancer: People are more at risk of developing colon cancer if they are obese, smoke, have type 2 diabetes, or eat a diet high in red or processed meats. Colorectal cancer can be prevented through regular screening that enables doctors to detect precancerous polyps and remove them before they turn into cancer.  

Lung cancer: Smoking is the leading cause of lung cancer.8 People often don’t have symptoms until their cancer reaches an advanced stage, which makes treatment more challenging. Depending on the type of lung cancer, treatment may include surgery, radiation, chemotherapy, immunotherapy, and/or targeted drug therapy. 

Together, we can drive breakthroughs that change lives. 

At Conquer Cancer, we raised $12 million in 2025 alone and more than $154 million since 1984. Our mission remains to accelerate breakthroughs in lifesaving research and empower people everywhere to conquer cancer. Your support allows us to fund talented researchers as they pioneer bold, new approaches to prevention and treatment. 

Research fuels progress, and progress starts with you. Together, we are building a world where cancer is prevented or cured, and every survivor is healthy.

Related Content: 

  • Hear Dr. Otis Brawley and Dr. Mark Lewis explain how cancer isn’t one “curable” disease, but rather hundreds of unique conditions requiring personalized, evolving management. Listen here.
  • Evolving research changed the survival story for Hattie Sherman and her hereditary breast cancer diagnosis. Read how.
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