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January 10, 2020

Scientists have yet to 'cure' cancer, but significant advancements have improved survival rates

From immunotherapy to enhanced screening methods, cancer patients are way better off than when President Nixon declared 'War on Cancer'

Cancer touches almost everyone – one in two men and one in three women can expect a cancer diagnosis at some point in their lifetimes.

This is why so many people are personally dedicated to fight it, from the hospital to the laboratory, and through generous donations of time and philanthropic support. Since 1971, when President Nixon declared a “War on Cancer” and signed the National Cancer Act, the United States has committed billions of dollars toward cancer research.

Why then is there no cure? Will there ever be a cure, and how much longer will it take until we find one? The answers are complex. But here is what is clear: Progress in the last decade has been exponential and patients are benefitting.

First, it is important to know that we are not seeking a cure. Cancer is not a single disease, but a collective grouping of more than 200 diseases that are distinct from each other, arising from different causes that respond differentially to treatment. Ironically, the more we learn, the more cancer types we find! It is unlikely that we will find a universal cure that effectively treats all cancer types. We also should reconsider the word “cure.” We might not be able to cure all cancers, but rather manage them as a chronic disease, like diabetes.

Understanding the differences between tumor subtypes through cancer research has led to major advances and increased cancer survival rates. For example, there are two main types of lung cancer, non-small cell lung cancer and small cell lung cancer, as well as additional subtypes within these categories. The different tumor subtypes may not originate in the same parts of the lungs, grow or spread at the same speed, or respond to the same treatments. Breast cancer is not one single disease, but at least five major cancer subgroups that all require different therapeutic interventions.

In addition, cancer is as unique as every individual is because it is affected by complex factors unique to each individual. Cells do not grow independently of their environment, but are greatly influenced by the biome, or eco-system, in which they live. For example, cancers that have metastasized (spread) to the bone can act very differently than the same cancer that metastasizes to the liver. The biome includes the microenvironment that directly surrounds the tumor, the patient environment that is affected by factors like genetics, and the physical community that is affected by the food we eat, living conditions, stress and sociodemographic factors.

Scientists are still making discoveries about the basis of cancer development and progression, which provide insights and breakthroughs that we are able to translate into new therapies for patients.

These breakthroughs can take decades to develop into safe, effective treatments for patients – and sometimes what works in the lab does not translate to people. But we are seeing these efforts come to fruition. Between Aug. 1, 2018, and July 31, 2019, the U.S. Food and Drug Administration approved 17 new anticancer therapeutics, according to the American Association for Cancer Research’s Cancer Progress Report 2019. The FDA also granted 10 new approvals to treat additional cancer types to previously approved therapeutics in this short timeframe.

We are making great strides against cancer on multiple fronts. For many years, the only treatment options for cancer were surgery, radiation therapy and chemotherapy. Now there are other options, such as immunotherapy or targeted therapies, many of which received FDA approval just in the past decade.

While we often rely on the standard treatments because they still are the most effective therapies in many cases, we have improved upon them. For example, we have found that a shorter chemotherapy regimen works just as well as a longer one to treat certain cancers. Numerous clinical trials are underway to confirm that a combination of older and newer treatments, such as chemotherapy plus immunotherapy, are more effective together than either on their own.

We are also getting much better at cancer prevention and screening for early detection.


Karen E. Knudsen, Ph.D.

The HPV vaccine is a remarkable advance. HPV infection causes nearly all cases of cervical cancer and many cases of other cancers as well, including head and neck, anal, vaginal and penile cancers. The vaccine can prevent these cancers from ever developing.

Although smoking is still the leading cause of preventable death in the United States, the smoking rate, which was 42.4% in 1965, is the lowest it has ever been – and it continues to decline. In 2017, 14% of adults in the U.S. smoked compared with 20.9% in 2005, according to the Centers for Disease Control and Prevention. The next best thing to prevent cancer entirely is to find it early, when it is more treatable. Breast, prostate, cervical, colorectal, lung and skin cancers can all be screened for and have very good survival rates when caught early.

Finally, genetic testing to identify inherited gene mutations that increase cancer risk is an evolving field related to cancer prevention and early detection. Researchers are gaining a deeper understanding of inherited cancers while developing methods to better identify people who should undergo genetic testing. Philadelphia is proud to have opened the first men’s genetic testing clinic for prostate cancer in the country, housed at the Sidney Kimmel Cancer Center at Jefferson.

Most importantly, these collective advances have dramatically improved cancer prevention and cancer care. As recently as in the mid-1970s, the five-year relative survival rate among adults for all cancers combined was only 50%. Breakthroughs in cancer research and cancer care delivery have improved survival rates to 68% on average, with some cancer diagnoses further exceeding that average. For example, some early stage Hodgkin lymphomas and cervical cancers have a five-year relative survival rate over 90%. Among some early stage melanomas, breast, prostate, testicular and thyroid cancers, the five-year relative survival rate is over 95%.

We have the privilege of treating these patients every day and they are a wonderful reminder that the small, steady steps of the past 40 years have truly made a difference. The outstanding National Cancer Institute-designated cancer centers in Philadelphia have pioneered the cancer research discoveries and clinical trials that continue to improve lives and accelerated the path to cancer cures.

Karen E. Knudsen, Ph.D., enterprise director at the Sidney Kimmel Cancer Center – Jefferson Health, oversees cancer care and cancer research at all SKCC sites in the Greater Philadelphia region. She writes occasionally on topics related to cancer.

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