Former US President Joe Biden has been diagnosed with an aggressive form of prostate cancer that has spread to his bones.
Biden received the news on Friday after he saw a doctor last week for urinary symptoms.
Here's what you need to know about prostate cancer and its treatment options.
The former president's prostate cancer is "characterised by a Gleason score of 9", his office said in the statement announcing his diagnosis.
In the US, the Gleason score is a common way of grading the capacity for cells from the primary tumour to spread round the body - also known as metastatic cancer.
Specifically, it refers to how abnormal the cancer cells look in a sample under a microscope. The scale runs from six to 10, with a higher number indicating a more aggressive cancer.
The scale starts at six because it is calculated by combining the two most common patterns of cancer cells found in a patient. The lowest score assigned to cancerous cells is three. That's why the lowest Gleason score for a cancer diagnosis is six.
A Gleason score of nine, such as Biden's, means it is a "high-grade cancer". Cancer cells with a score of nine look very abnormal and are likely to grow quickly.
Biden's cancer is aggressive in nature and has already spread to his bones.
According to Dr Jamin Vinod Brahmbhatt, a urologist at Orlando Health Medical Group, this level of spread does limit the treatment options.
While there are medical based treatments such as chemotherapy, steroids and hormone therapy available, none of them are "curative", he said.
"There are more medical options to stabilise the patient and control the cancer, but it never gets rid of the cancer completely."
Biden's cancer is also said to be hormone sensitive, which means the cancer uses hormones to grow or develop.
These types of cancers can be managed by drugs that block or lower the amount of hormones in the body.
Dr Brahmbhatt said while this "opens up the toolkit" of treatment options for Biden, it was going to take "weeks or months" to see how he responds.
Dr Kuhlman said Biden could also have the option of entering "clinical trials for advanced disease" if he meets the inclusion criteria.
Biden and his family are said to be reviewing treatment options.
In Sunday's statement, Biden's office said since the cancer appeared to be hormone-sensitive, that "allows for effective management".
The full details of Biden's case are not known. Dr Cleary said: "Generally, about a third of patients will still be alive after five years of metastatic prostate cancer."
However, advanced stages of prostate cancer can limit a person's lifespan and lead to symptoms that make daily life harder.
Dr Kuhlman said it was important to consider treatments that maintain Biden's quality of life in the next few years.
"If there's any inspiration in this, it is to go and get yourself checked out whether you have symptoms or not," Dr Brahmbhatt said.