Colon Cancer ScreeningAlison Little, MD, MPH

Medical Director, Medicaid

Colon Cancer Screening

 

Colon Cancer Screening

Overdiagnosis

When an individual is diagnosed with a condition that will never cause

symptoms or death

Colon Cancer Screening

Overdiagnosis

Makes people feel vulnerable and less healthy

Leads to excessive treatment, which can cause significant harm

Colon Cancer Screening

Overdiagnosis Case Study

Lara – 55 yo W female - asymptomatic• Screening DEXA finds T score + -1.8, started HRT • HRT stopped after WHI study• Put on bisphosphonate, developed severe esophagitis

(diagnosed by EGD)• Put on raloxefine, developed painful rash• Sent to endocrinologist to treat her osteopenia• Endocrinologist exams her thyroid, finds a mass• Has ultrasound, finds 3 nodules• Had a needle biopsy, finds possible malignancy• She gets lucky…. The surgeon she is referred to stops, noting

that there are 1600 annual deaths from thyroid cancer per year in US, compared to 37,000 diagnoses

Colon Cancer Screening

Examples of overdiagnosis (lower and lower threshholds for “disease”, better and better ways of finding abnormalities):• Hypertension• Diabetes• Hyperlipidemia• Osteoporosis• Gallstones• Meniscal tears• Vertebral disc disease• Aortic aneurism• Cancer

– Breast– Prostate– Thyroid– Lung– Melanoma

Colon Cancer Screening

Two cancers with little or no overdiagnsois: Colon and Cervical

Colon Cancer:– Screening for 25 years– Number of diagnosis has not risen, but instead has

fallen since 1985– Number of deaths from colon cancer has also fallen– If this was due to finding cancer precursors and

removing them, true success story– But, polypectomy uncommon until mid 1990s, 10

years after the onset of the decline in colon cancer

Colon Cancer Screening

Overdiagnosis associated with colon cancer screening is diagnosis of polyps

Many polyps removed that will never become cancer

Identification of polyps results in increased screening, and associated harms of overdiagnosis

Colon Cancer Screening