Brief Answer:
5%

Detailed Answer:
The risk of cancer in a cold thyroid nodule is about 5%.

Recent thyroid nodule guidelines have reinforced relatively new concepts in the field of thyroid nodule management which include the following:

1 There are other characteristics on ultrasound that can help make the distinction between cancer and benign nodules:

Size
Shape
Margins
Pattern and Distribution of blood flow
Calcifications
Abnormal neck lymph nodes

2 Biopsy (Ultrasound Guided Fine Needle Aspiration) is a most useful test in differentiating between cancer and benign nodules.

3 Other risk factors such as
Personal history of thyroid cancer
Family history of thyroid cancer
Radiation exposure to the head and neck area
Findings on physical examination

also matter

So it is not as simple as 5% risk of cancer in a cold nodule. Dozens of other factors are taken into consideration before the risk of cancer in a given nodule can be estimated.

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Brief Answer:
No

Detailed Answer:
To the best of my knowledge, there is no published medical literature that suggests this.
In fact guidelines are now recommending that if the TSH is normal or high, there is no need to perform thyroid uptake and scan tests that label nodules as hot, warm or cold.
This has been the trend for the last several years. About a decade ago it was common practice to routinely order these scans for all nodules. In fact, many non-endocrinologists still continue to run this test for thyroid nodules and then everyone has to deal with these cold nodule(s) situation, when current best practice recommends clinical and ultrasound-based evaluation along with (preferably Ultrasound-guided) Fine Needle aspiration biopsy as the best approach.

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