BOGOTA -- Colombia’s ailing Vice President Angelino Garzón said he has prostate cancer and opened the door to stepping down from the office, which he has held since 2010. The announcement comes weeks after President Juan Manuel Santos also underwent surgery for prostate cancer.

In a statement Monday, Garzón, 65, said doctors who were treating him for a stroke he suffered in June had found a non-aggressive “microscopic cancerous tumor” in his prostate, and that he would undergo 39 sessions of radiation therapy that would last at least five weeks.

“At this stage of my life I cannot cling to the vice presidency,” he said in a statement. “I fully understand that I must leave everything that has to do with the present and the future of the vice presidency of Colombia in the hands of the Constitution and the law.”

Garzón had a stroke in June that left him with limited mobility on one side of his body. While he has been recovering, some in congress have questioned his ability to hold the office.

Garzón, a former union leader with strong ties to Colombia’s left, was named Minister of Labor in 2000 under the administration of Andrés Pastrana, and then became governor of Valle del Cauca in 2003.

After winning the 2010 election as a Santos’ running mate, Garzón’s public criticism of the administration sometimes put him at odds with his boss and fueled speculation that the two were hoping to part ways. Last year, Garzón made a failed bid to lead the International Labor Organization. In September, as he was convalescing from the stroke, Santos said his administration would consider eliminating the vice president’s office altogether.

The presidency on Monday did not immediately issue a statement about Garzón’s health.

Santos had prostate surgery Oct. 3 to remove a cancerous tumor, and said he has made a full recovery. That made him one of at least three sitting leaders in the region who have had cancer. Brazil’s Dilma Rousseff was treated for lymphoma in 2009, and Venezuela’s President Hugo Chávez announced earlier this year that he had recovered from an undisclosed form of cancer that he first announced in 2011. Argentina’s President Cristina Fernández de Kirchner underwent surgery for suspected thyroid cancer, but later reported it was benign.