Former president Joe Biden’s newly diagnosed prostate cancer, an aggressive form that has spread to his bones, has renewed the debate about who should receive annual screenings for signs of the disease. Prostate cancer, the second most common cause of cancer deaths for men, kills 35,000 a year.

Sunday’s announcement of Biden’s illness incited unsubstantiated speculation online that the former president could have known long ago, perhaps through testing or symptoms, that he had cancer. His medical records as president do not indicate whether his blood tests included screening for prostate-specific antigen (PSA), which, when elevated, can indicate a higher risk of prostate cancer.

But it would not be unusual for a man Biden’s age to skip that kind of screening, according to prostate cancer experts who spoke to The Post but were not involved with his treatment or diagnosis.

“For most cancer screenings, there is an age when we say, no more screening,” said Michael Morris, head of the prostate cancer section at Memorial Sloan Kettering Cancer Center in New York City. “The majority of prostate cancers that are diagnosed are not the aggressive kind that we’ve been reading about [in the Biden stories]. Most prostate cancers are not a threat to a man’s longevity.”

The U.S. Preventive Services Task Force, which makes medical recommendations about preventive services such as screenings, recommends against screening in men 70 years and older. For men ages 55 to 69, the decision should be an individual one, it says.

The guidelines note that “many men will experience potential harms of screening, including false-positive results that require additional testing and possible prostate biopsy; overdiagnosis and overtreatment; and treatment complications, such as incontinence and erectile dysfunction.”

The American Cancer Society does not recommend routine testing for prostate cancer for men of any age. It recommends that men discuss screening with their provider at age 40 for those with more than one first-degree relative with prostate cancer at an early age; at age 45 for those at high risk, including African American men with a first-degree relative diagnosed at an early age; and age 50 for those at average risk.

However, the ACS says in its recommendations that “because prostate cancer often grows slowly, men without symptoms … should not be offered prostate cancer screening because they aren’t likely to benefit from it.”

The American Urological Association’s guidelines are the most aggressive. It recommends that screening be offered beginning at age 40 for men at high risk and that physicians offer regular screening every two to four years for people age 50 to 69. The guidelines do not mention recommendations for men 70 or older.

Phillip Koo, chief medical officer at the Prostate Cancer Foundation, said the risk-benefit analysis for screening has changed in recent years. The foundation recommends increased screening.

Koo said the number of treatment options has multiplied and the main treatment for early prostate cancer — removing the tumor — is now mostly done by laparoscopic or minimally invasive surgery, which involves only tiny incisions made by robots. For many patients, it can be an outpatient procedure.

“The take-home message is patients can be their own biggest advocates and have the biggest impact on their lives by early detection and treatment,” Koo said.

Biden’s office said doctors detected a nodule on the former president’s prostate and microscopic analysis detected cancerous cells. His cancer received a Gleason score of 9 on a scale that goes up to 10, meaning it is aggressive. A subsequent scan revealed the cancer has spread to bone.

As part of his medical checkup while in office, President Barack Obama did have his PSA levels checked, which is consistent with screening guidelines that suggest African American men and their providers consider screening as early as age 40. Obama was 47 at the start of his presidency.

President Donald Trump had his PSA checked in April this year. It was normal.

The path ahead for Biden, 82, will probably involve hormone therapy to block the production of testosterone, which feeds prostate cancer in the same way that estrogen is associated with breast cancer.

“It’s like a car — the engine making that car go is a molecular engine called the androgen receptor. And so testosterone is the gas for that engine, and PSA is the exhaust,” said Peter Nelson, a prostate cancer researcher at the Fred Hutchinson Cancer Center, which is affiliated with the University of Washington School of Medicine.

“Men get an injection of an ‘antihormone’ to lower testosterone to extremely low levels. We learned that does a great job initially, but some androgen is still around. So if you add a second drug that further blocks the gas tank, you can improve survival by several years,” Nelson said.

The hormone therapy can extend a cancer patient’s life but typically includes significant side effects, such as fatigue, hot flashes, cognitive issues, weight gain, loss of libido, lower bone density and risk of fractures, oncologists told The Washington Post.

“The side effect of uncontrolled metastatic disease is much worse than hormonal therapy,” said Morris, the Memorial Sloan Kettering Cancer Center physician. “You die from uncontrolled metastatic disease, and hormone therapy prolongs life and prevents the onset of symptoms from metastatic disease,” including pain.

Otis Brawley, a Johns Hopkins University medical oncologist who treats patients with metastatic prostate cancer, said the hormone therapy can be psychologically difficult for patients.

“I see a lot of guys who struggle with those drugs. I know a lot of guys who refuse to take them because they don’t want these drugs to interfere with their nature,” Brawley said.

But an older patient may find the therapy less jarring, Brawley said.

“The older guy has gotten a little bit better acclimated to the lower androgen, so lowering it a little bit more is going to be less of a side effect,” he said.

Several prostate cancer specialists, including William Dahut, chief scientific officer of the American Cancer Society, said the average life expectancy at diagnosis for someone with metastatic prostate cancer that has spread to the bone is in the range of three to five years, though some patients can live quite a bit longer.

Dahut said there are limited details about Biden’s case, and his prognosis could depend on many factors yet unknown.

That includes the degree of bone spread, any symptoms from bone lesions and whether the cancer has spread to organs such as Biden’s liver, Dahut said.

Another important factor will be the initial degree of response to hormonal therapy, he said.