SINGAPORE - Prime Minister Lee Hsien Loong has been diagnosed with prostate cancer and will undergo surgery to remove his prostate gland, the Prime Minister's Office said on Sunday.

Prostate cancer occurs when a malignant tumour forms in the tissue of the prostate, a gland in the male reproductive system located below the bladder.

The condition is the third most common cancer among Singaporean men. Emeritus Senior Minister Goh Chok Tong underwent successful surgery at Singapore General Hospital for prostate cancer in November last year.

Prostate cancer tends to affect those above the age of 50, with the likelihood increasing as one gets older.

Smokers and those with a family history of prostate cancer are also at higher risk of developing the condition.

Symptoms include a need to urinate frequently, painful urination and blood in the urine or semen.

In early stages of the cancer - when it is confined to the prostate gland - the condition can be treated by removing the prostate gland and nearby tissue. Patients can also opt for chemotherapy and external beam radiation therapy.

While there are no proven methods that prevent prostate cancer, regular exercise, a balanced diet and abstaining from smoking are helpful measures, doctors say.

The cancer can be detected through blood tests, ultrasounds and rectal examinations.

From 2009 to 2013, 3,456 people in Singapore were diagnosed with having prostate cancer.

According to statistics, Chinese men have a higher risk of developing the cancer, compared to Malay and Indian men.