Overtreatment” of tumor is often mentioned by people. It refers to the treatment methods such as radiotherapy and chemotherapy to kill tumor cells, which cause more harm to the human body and put the cart before the horse, and the loss is not worth the gain. Do you understand the “overdiagnosis” of tumor? Overdiagnosis refers to the detection of early-stage cancer by screening, some of which may never progress to the stage of mid- to late-stage cancer with clinical symptoms, and these patients are “overdiagnosed”. Two American scholars, Dr. A. Bleyer and Dr. G. Welch, introduced this concept in a recent issue of the New England Journal of Medicine and noted that 1.3 million breast cancer patients in the United States have been “overdiagnosed” in the past three decades. His theory is based on the following analysis. First, the incidence of early-stage breast cancer in the United States nearly doubled from 112 per 100,000 to 234 per 100,000 in the more than 30 years since mammography was adopted as a screening method for breast cancer between 1976 and 2008. In contrast, there has been only a small (8%) decline in the incidence of intermediate and late stage breast cancer, from 102 per 100,000 to 94 per 100,000. The goal of screening is to increase the rate of early tumor diagnosis and decrease the incidence of intermediate and late stage. Generally speaking, the incidence rate of cancer in the population is a relatively stable rate that does not fluctuate greatly in the short term. On this basis, if the early cancer diagnosis rate increases because of improved screening means, the incidence rate of the remaining middle and late stage cancers will definitely decrease. And the above data show that screening only improves the detection rate of early-stage cancer, but does not reduce the incidence rate of middle- and late-stage cancer. This suggests that many of the detected early-stage cancers may not develop into mid- to late-stage clinical cancers. This group of patients may be “over-diagnosed”. Second, the mortality rate of breast cancer patients has decreased significantly. Over the past four decades, the mortality rate for breast cancer patients in the United States has declined from 71 per 100,000 to 51 per 100,000, a reduction of 28%. This is often attributed to the prevalence of breast cancer screening and the increase in the rate of early diagnosis of patients. However, an analysis of the above data shows that screening is not a major factor. The difference between the 8 per 100,000 reduction in incidence and the 20 per 100,000 reduction in mortality for all patients in the middle and late stages, which account for the largest proportion of breast cancer deaths, suggests that improved treatment outcomes for patients in the middle and late stages are a major factor in the reduction in mortality. The group of patients with early-stage cancer who were “overdiagnosed” did not benefit in a group sense. In their article, the two scholars point out that the current emphasis on early diagnosis and early treatment in cancer treatment is due to the limited availability of cancer treatments and poor treatment outcomes. If treating cancer was as effective as treating pneumonia, then we would not need to screen for cancer at all, just as we never screen for pneumonia now. This concept is at odds with the current mainstream notion that cancer needs to be diagnosed early and treated early for optimal outcomes. The concept was met with much skepticism when it was proposed. For example, Kopans, an American breast cancer expert, severely criticized this view, suggesting that the rising incidence of early breast cancer should not be attributed to overdiagnosis, but should take into account the changes in the incidence of cancer itself as times and environments change. Dr. Bleyer explained that in their study, they had calculated that 1.3 million patients were “overdiagnosed” based on a normal annual increase of 0.25% for breast cancer. Even at the higher level of 0.5% annual growth rate, that’s 1.2 million people. The concept of “overdiagnosis” in oncology will be a point of debate for a long time. Overdiagnosis does not mean that cancer screening is useless. At this stage, screening is the best outcome for each individual to detect early latent cancer and provide targeted treatment. The significance of this view is to raise awareness of oncology treatment, especially among medical practitioners. It raises the possibility that some early-stage cancers, even without intervention, may heal themselves or remain hidden for a long time without transforming into clinically significant mid- to late-stage cancers, and it is refreshing to find more informative supporting evidence. However, longer-term observations and studies are needed to confirm the correctness of their views, and it is hoped that more medical practitioners will join them.