Evaluation of mass screening for thyroid cancer

Area of Science:

• Oncology
• Public Health
• Epidemiology

Background:

• Mass screening programs are crucial for early disease detection.
• Thyroid and breast cancer screening in adult women was conducted in Gunma Prefecture, Japan.
• A large cohort of 152,651 women participated between 1980 and 1986.

Purpose of the Study:

• To evaluate the effectiveness of mass screening for thyroid and breast cancer detection.
• To determine the incidence and characteristics of thyroid cancer identified through screening.
• To compare the stage and survival rates of screen-detected thyroid cancer with outpatient cases.

Main Methods:

• Initial screening involved visual inspection and palpation by experienced surgeons.
• Subjects with abnormalities were referred for a second examination.
• Histopathological analysis was performed on detected thyroid cancers.

Main Results:

• Thyroid abnormalities were found in 3.9% of subjects, with 2.5% requiring further examination.
• A total of 216 thyroid carcinoma cases were detected, yielding a 0.14% detection rate.
• The detection rate was higher during initial screening (0.19%) compared to periodic screenings (0.09%).
• Papillary carcinoma (87.5%) was the most common type; 87% of cases were asymptomatic.
• 58.3% of detected tumors were 2 cm or less.
• Screen-detected thyroid cancer presented at an earlier stage with significantly better survival rates.

Conclusions:

• Mass screening is effective for the early detection of thyroid cancer.
• The program identified a high proportion of asymptomatic thyroid cancers, often at an early stage.
• Early detection and treatment of thyroid cancer through mass screening improve patient survival outcomes.