Medical experts from across the world have gathered in southwest China's Chengdu City to discuss the latest research on the spread of cancer cells in the body. The four-day event, which started on Thursday, is known as the 16th Biennial Congress of the Metastasis Research Society.

This is the world's top-level gathering on metastasis research.

And it is in China for the first time, three decades after the group's creation.

Zhou Qinghua, the President of the current congress, started the idea back in 2003.

"Before this congress, Chinese people have never held a meeting in the field in such a big scale. We aim to invite international experts to interact with Chinese ones. Besides, we aim to exhibit China's achievements and progress in the field," Zhou said.

Mr. Sleeman began the study of metastasis back in 1980s.

He hails China's achievements in the field in recent years.

Medical experts say lung cancer has been the number one killer of cancer patients in China since from the 1990s.

Mr. Shen was diagnosed with lung cancer in 2004.

He got an operation in 2006 by Prof. Zhou Qinghua after the cancer cells spread.

"My feelings before and after the operation are totally different. I thought I was living in a hopeless darkness, but after that I am getting much happier day by day," Mr. Shen said.

Mr. Kang is now studying cancer metastasis at Princeton University.

He points out it's crucial to know the mechanism before seeking specific treatments.

The congress is expected to provide an opportunity for Chinese medical experts to get connected with the international research community.

But Mr. Zhou Qinghua says, the ultimate goal is to help cancer patients recover and foster a new generation of young talents.