Less than two years after getting a liver transplant, Apple CEO Steve Jobs is taking a medical leave of absence to focus on his health, the company announced Jan. 17, 2011.

“At my request, the board of directors has granted me a medical leave of absence so I can focus on my health,” said Jobs, 55, whose medical leave extends through June 2011.

“I will continue as CEO and be involved in major strategic decisions for the company.”

In the interim, Apple COO Tim Cook will run day-to-day operations for the company. Without providing additional details, Steve said he hopes to return to work soon.

Jobs, who underwent a liver transplant in April 2009, was treated for pancreatic cancer in 2004.

Pancreatic cancer has the lowest survival rate of any type of cancer, but Jobs insisted that he had a rare, less aggressive type known as islet cell neuroendocrine tumor.

Steve, who lost a dramatic amount of weight in recent years due to illness, treated his pancreatic cancer by undergoing a pancreaticoduodenectomy (aka – Whipple procedure) in July 2004 that apparently removed the tumor. Jobs reportedly did not require chemotherapy or radiation therapy and has insisted he’s has been in good health and recovery since then.

Sadly, the survival rate for pancreatic cancer is extremely low. It spreads quickly and is usually discovered too late. According to the American Cancer Society, the one-year relative survival rate is 20%, and the five-year rate is 4%.

The tragically low survival rate is due to the fact that fewer than 10% of tumors are confined to the pancreas at the time of diagnosis; in most cases, it has already progressed to the point where surgical removal is impossible.

Samantha Chang is the executive editor of TheImproper and a celebrity writer at Examiner.