A total of about 1.9 million cancer diagnoses and 609,820 cancer deaths are expected in the United States in 2023, and it remains the second leading cause of death in the country until the present. Despite these high rates, there has been a substantial decline of 33% in cancer deaths due to early detection, advancement in treatments, and reductions in smoking.
What is early cancer detection?
Proposed in 1968 by Wilson and Jugner of the World Health Organization, early detection consists of two components—early diagnosis (or downstaging) and screening. The former focuses on detecting cancer (of any type) among symptomatic patients as early as possible, while the latter includes testing (for specific types of cancer) those who are at risk and don’t have symptoms yet.
Since screening is only applicable to certain types of cancer, the current guidelines from the American Cancer Society and the US Preventive Services Task Force recommend screening individuals for cervical, colorectal, breast, and prostate cancers based on age and population. In addition, current and former heavy smokers are recommended to get screened for lung cancer and those with hepatitis B or C infection and cirrhosis for hepatocellular cancer.
Some examples of cancer screening tests are imaging, tissue sampling, and serial exams. For more information, check out How to Detect Cancer Early.
How can early detection improve patient outcomes?
When cancer is detected at an early stage, or when it’s not too large or has not spread, there can be more successful patient outcomes. In most studies, patients who have been diagnosed at earlier stages (stage I-II cancer) showed improved survival, reduced mortality, and improved quality of life.
- Improved survival and reduced mortality
About half of cancer cases are diagnosed at a late stage, where cancer has already spread to other parts of the body, thereby decreasing survival chances. For example, between 36 and 53% of patients with stomach, pancreatic, or non-small cell lung cancer have been diagnosed at stage IV, so they have lower chances of survival.
Early detection of cancer or precancerous change is then important to improve the survival chances of cancer patients because it allows early intervention or treatment that can slow down or prevent cancer development and lethality.
Lung cancer patients have a survival rate of 57% when the disease is localized during diagnosis. This can be reduced to 5%, though, if the cancer is in its metastatic form during diagnosis. For some cancers, however, the stage of detection is less significant. To cite an example, prostate cancer has around 100% one-year survival rate regardless if detected in stages 1, 2, or 3 and falls to 87.6% if detected in stage 4.
In terms of mortality rate, a meta-analysis conducted by the US Preventive Services Task Force showed a 15 to 20% mortality reduction for breast cancer patients through mammography screening and a 20 to 60% mortality reduction for cervical cancer patients who have undergone cytology-based screening. Additionally, the International Agency for Research on Cancer reported a 22 to 31% mortality reduction for individuals with colorectal cancer after having gone through sigmoidoscopy screening.
- Improved quality of life
When combined with prompt treatment, early detection of some cancers permits less aggressive treatment. This means that the patient, as well as their caregivers, can have a better quality of life. When a patient goes through a more intensive and invasive treatment, as necessitated by later-stage diagnoses, he may experience difficult and lasting side effects, thus declining his quality of life physically, emotionally, and socially.
As an example, non-small cell lung cancer patients with late-stage diagnosis often suffer from labored breathing (also called dyspnea) after the treatment completion. Similarly, late-stage stomach cancer patients who have received a partial or full gastrectomy and follow-up treatments like chemotherapy, radiation therapy, and immunotherapy may suffer from chronic fatigue, difficulty eating, and challenges performing regular daily activities.
Limitations of early cancer detection
Unfortunately, early cancer detection through screening remains limited. In the US, countrywide cancer screenings for asymptomatic patients only apply for just specific cancer types—breast, prostate, cervical, colorectal, and lung for high-risk individuals. Therefore, the majority of cancer mortality comes from cancers that are not covered in this broad-based screening.
On another note, medical and socioeconomic barriers also exist, making early detection limited. Some of these limitations include:
- Lack of symptoms
Because some cancers do not present symptoms at an earlier stage, they are often diagnosed at an advanced stage.
Some people are not aware of the signs and symptoms of their cancer, and think that they have another health condition. Because of that, they are diagnosed and treated when their cancer has advanced.
Not all have sufficient access to early detection methods like early diagnosis and screening, thus delaying their diagnosis and treatment.
- Financial status
People who come from low socioeconomic status are less likely to obtain early detection. They also tend to become reluctant about the signs and symptoms they experience due to other priorities.
Even if doubt of having cancer exists, some people might still fear getting diagnosed with cancer. Treatments that come with it may also cause them fear due to their lasting side effects as well as economic cost.
- Human nature
Many young people reject the need for screening because they feel healthy and invincible. However, rates of cancer linked to obesity are increasing among adults younger than 50 years. Therefore, everyone should watch out for symptoms and high-risk individuals should go through screening to avoid complications.
For higher chances of getting successful patient outcomes, studies have proven that early detection through early diagnosis and screening is effective. Remember that the efficacy of treatment is better when cancer is addressed at an earlier stage.