"Cancer is most curable when it's detected at its earliest stages. While it is much too soon to identify the specific cause of this positive trend, or determine whether it is sustainable and will improve outcomes, it is indeed a step in the right direction," said ASCO President-Elect Bruce E. Johnson, MD, FASCO.

An analysis of nearly 273,000 patients showed that between 2013 and 2014 there was a 1% increase in the percentage of breast, lung, and colorectal cancers diagnosed at the earliest, most treatable stage. Considering the thousands of people diagnosed with these cancers annually, a 1% increase in early-stage diagnosis could add up to a significant number of new cases and potentially lead to better outcomes.

Following full implementation of the Affordable Care Act (ACA), this study is the first to explore changes in the proportion of cancers -- those that can be detected through screening -- diagnosed at stage I. The ACA has had a measurable impact on increasing the number of people with health insurance in the United States. The findings will be presented at the upcoming 2017 ASCO Annual Meeting in Chicago.

"We know from previous research that lack of insurance typically results in diagnosis of cancer at a later, and usually less treatable, stage," said lead study author Xuesong Han, PhD, Strategic Director, Health Policy and Healthcare Delivery Research, American Cancer Society. "Although we only analyzed data from a limited timeframe, the fact that there appears to be a positive trend in diagnosis at an earlier stage in multiple cancers is an encouraging sign."

About the Study

The five types of cancers analyzed in this study have screening methods that allow for detection at an early stage, though in some instances, debate remains over efficacy and appropriate use: mammography for breast cancer, colonoscopy for colorectal cancer, Pap smear and/or HPV test for cervical cancer, spiral computed tomography or CT for lung cancer, and PSA test for prostate cancer.

In this study, researchers from the American Cancer Society used the National Cancer Database, a registry of cancer cases reported by hospitals across the United States, which captures about 70% of newly diagnosed cancer cases each year. They focused on patients under 65 years of age who were eligible for cancer screening and diagnosed in 2013 or 2014. As the ACA was implemented in late 2013, the researchers used the first nine months of 2013 as a baseline and compared trends in cancer stage at diagnosis in this period to those in the last nine months of 2014.

Key Findings Researchers found a 1% increase in stage I diagnoses for four of the five cancers detectable by screening: breast (from 47.8% to 48.9%) and cervical cancer (47.3% vs. 48.8%, although this difference was not statistically significant) in women, and lung (from 16.6% to 17.7%) and colorectal cancer (22.8% vs. 23.7%) in men and women. The exception was prostate cancer for which the percentage of stage I diagnoses fell by 1% (from 18.5% vs. 17.2%).

More research is needed to see if this shift in stage at diagnosis is a short-term effect or continues over time.

Next Steps

The researchers plan to follow cancer diagnosis trends over the coming years. They also plan to look beyond these five cancers and examine patterns in population databases that are more generalizable.