A grade 4a thyroid nodule is not necessarily thyroid cancer, and if it is indeed thyroid cancer it is not necessarily early. Thyroid 4a refers to a thyroid nodule graded 4a on thyroid ultrasound, a common classification for thyroid nodules on clinical imaging.
The ultrasound classification of thyroid nodules is usually classified as 1, 2, 3, 4a, 4b, or 4c. Grades 1, 2, and 3 are usually clinically indicative of benign nodules, and if the nodule is small and there is no clinical pressure on the neck, such as breath holding or neck discomfort, it can be left alone and only requires follow-up thyroid ultrasound. The higher the grade of the nodule, the closer the follow up.
And a grade 4a thyroid nodule is one that is suspected to be malignant to some degree, with a chance of malignancy of about 5%. But as to how far the tumor has progressed is not clearly determinable, in other words if it really is thyroid cancer, it is not certain if it is early. In this case, further puncture biopsy is needed to determine the benignity or malignancy or to consider surgery directly.