I know the term "game-changing" is used too often to describe stocks that don't change the game at all. Not every innovation that comes along will disrupt an industry. Not every stock that seems to have a revolutionary product or service really sparks a revolution.

That being said, there truly are some game-changing companies that are publicly traded. You don't want to make short-term trades with these stocks just to capture a quick gain. They're the kinds of stocks that are what the buy-and-hold style of investing is all about.

Granted, there aren't many stocks that meet these criteria -- but there are a few. Here are three game-changing stocks that you can buy and hold for the next 20 years and probably even longer. 

A person's hands beneath an image of Earth with a network of lights around it

Image source: Getty Images.

1. Guardant Health

We've seen remarkable progress over the last decade in how cancer is treated. But many people don't realize the strides that have also been made in how cancer is detected. One especially notable (and I'd argue game-changing) development is liquid biopsies -- blood tests that determine the presence of cancer, along with the type of cancer, by analyzing fragments of DNA that break off from tumors.

Guardant Health (GH 4.38%) stands as one of the leaders in the field of liquid biopsy. In August, the company's Guardant360 CDx became the first liquid biopsy product for identifying specific tumor mutations across all solid cancers to win FDA approval. Guardant360 was already on the market as a laboratory-developed test, which is limited to use by single labs and has been a huge commercial success for Guardant Health.

The market for liquid biopsy products such as Guardant360 in advanced-stage cancer patients is around $6 billion annually in the U.S. alone. However, the market for early detection of cancer and recurrence monitoring is much larger, topping $45 billion in the U.S. plus a lot more in the rest of the world. 

Guardant Health already is evaluating two liquid biopsy products in clinical trials that target this larger market opportunity. The company has already reported early results that showed promise for its LUNAR-2 assay in detecting early stage colorectal cancer. With a market cap of less than $11 billion and a massive untapped market, this healthcare stock could be an enormous winner over the next two decades.

2. Intuitive Surgical

Robots have been used to assist surgeons perform procedures for 20 years. While the adoption of robotic surgery has increased significantly, most procedures today still don't involve robots at all. But expect an even more dramatic "rise of the robots" in surgery over the next two decades as technology improves.

Intuitive Surgical (ISRG -0.55%) pioneered the use of robotic surgical systems and is well-positioned to stay at the top of its market for a long time to come. Over 7.2 million procedures have been performed with Intuitive's da Vinci robotic surgical system. Nearly 5,800 da Vinci systems have been installed across the world.

Success attracts competition. Several companies have entered the robotic surgical systems market, including big players such as Johnson & Johnson and Medtronic. The market opportunities should be great enough to support multiple companies. Intuitive Surgical's large install base and extensive track record give it significant competitive advantages, though, that will be hard to overcome.

I think there are three key reasons why Intuitive Surgical will be a great investment over the next two decades. First, aging demographic trends across the world will drive higher demand for the kinds of surgical procedures that are ideally suited for robotic assistance. Second, Intuitive's technological innovation will enable robotic surgery to be used in more procedures. Third, the company will continue to expand into international markets, which present a much larger opportunity overall than the U.S. 

3. Sea Limited

When you think about e-commerce, I suspect a certain company named after a really long river in South America comes to mind first. However, there's a lesser-known e-commerce leader that's growing at a much faster rate than Amazon.com: Singapore-based Sea Limited (SE 2.03%).

Sea Limited's Shopee e-commerce platform ranks among the top three most downloaded shopping apps worldwide. It's the No. 1 e-commerce platform in Southeast Asia and in Taiwan in terms of average monthly active users.

But it wouldn't be accurate to refer to Sea Limited as only an e-commerce company. Sea Limited generates its highest revenue in online gaming. The company's Free Fire was the most downloaded mobile game worldwide in 2019 and was No. 3 globally in the second quarter of 2020. Sea Limited also claims a fast-growing digital payments business. Its SeaMoney mobile wallet is tightly integrated with Shopee and has been especially successful in Indonesia.

There's no doubt in my mind that e-commerce, online gaming, and digital payments will be much more widely adopted 20 years from now. And there's no question that the markets where Sea Limited currently targets, especially Asia and Latin America, will grow significantly during the period as well. Like Guardant Health and Intuitive Surgical, Sea Limited provides innovative solutions that I think will generate game-changing returns for investors over the long term.