Dr. Tsubokura's Radiation Lecture Vol.114

Author: Masaharu Tsubokura M.D., PhD.

Editors: Akihiko Ozaki M.D.,PhD., Yuki Senoo


227. The Aim of the Cancer Registry System Is to Understand the Number of Cancer Patients


When researching the post–nuclear disaster public health situation in Fukushima, one may encounter many figures used to express whether the number of the patients with certain illnesses has increased or decreased. While these figures enable us to comprehend the current circumstances at a glance, we must be aware of several things to understand what these figures represent.

In order to learn the current conditions regarding cancer and develop necessary countermeasures, it is important to determine the number of people with cancer and their status in various regions. In Japan, the Cancer Registry—a project to collect patient data systematically—was first started in the 1950s in Miyagi Prefecture. Other regions have adopted system gradually since 2016, and currently, it is available in every prefecture.

However, it is not easy to gather details on all cancer patients throughout Japan. When patients are diagnosed with cancer at hospitals, they are supposed to be registered to the Cancer Registry system. It is not hard to imagine how difficult it is for medical personnel to register all patients’ details, especially at hospitals suffering from a shortage of medical staff. In order to improve the accuracy of registered patients’ details, not only medical records but also data from health centers and municipalities are included in the registry system, which takes an enormous amount of time.

Although registration occurs on a prefecture-by-prefecture basis, patients often visit multiple hospitals located in different prefectures, and their addresses may change over time. It is also necessary to check whether the same patients have been registered twice.


As such, various attempts have been made to improve this registry’s accuracy. In this regard, this is not something that we can simply calculate with data from 1 specific hospital.

228. Caution Is Required with Oversimplified Phrases Such as “an Increased Number of Patients”


When researching the post-nuclear disaster public health situation in Fukushima, one may encounter many figures used to express whether the number of patients with certain illnesses has increased or decreased. While these figures enable us to comprehend the current circumstances at a glance, we must be aware of several things to understand what these figures represent.

The previous article explained how the assignment of a new physician could increase the number of patients visiting the hospital, and that as a result, it looks as if the number of patients with certain diseases increased in a particular region.

Additionally, as medical treatment and technology progress, the number of patients may appear to have increased. For example, when new and safer surgical procedures and instruments are developed, patients who were previously unable to undergo surgery will be able to receive the treatment. Moreover, progress in examination techniques and equipment will allow for larger numbers of patients to be detected.

When the practitioners’ guidelines for treatment are revised, some patients who were indicated to be treated with medication by the previous guidelines may be considered as suitable for undergoing surgeries. This change will apparently increase t