April 29, 2025 – Prostate cancer is thesecond-deadliest cancer among U.S. men – and it's on the rise. More than300,000 men are diagnosed with the condition each year, a number that's been climbing by 3% annually since 2014, according to the American Cancer Society.
The reasons come down to a few different things. Screenings have gone up, so more cases are being identified. People are living longer, and with prostate cancer, the number of new cases increases dramatically with age – from 0.2% among men under 50; to 2% for men over 50; 5% over 60; and 9% over 70. Although most cases are diagnosed early and progress slowly, one in 44 men will die from it.
But a new way to attack the disease is gaining pace in nuclear medicine: an advance known as theranostics.
The name, which combines"therapy" and"diagnostics," hints at the treatment's dual purpose: to identify cancer lesions and kill them on the spot with targeted radiotherapy.
How Does Theranostics Work?
The basic detect-and-destroy principle of theranostics dates back to the1940s, with the use of radioactive iodine to treat thyroid cancer. But recent advances in imaging technology and cancer treatment have led to huge strides in the field. Big drug companies like Novartis and Lillyhave invested billions in developing or acquiring radiopharmaceuticals, the radioactive drugs that make theranostics possible.
The diagnostic part of theranostics involves tests – often a PET scan – where a radiopharmaceutical drug known as radiotracer is infused into the patient and binds itself to cancerous cells, revealing them through the scans. For prostate cancer, the radiotracer binds to prostate-specific membrane antigens (PSMA) expressed by the cancer cells.
Following the same pathway, a therapy then targets the cancer cells, destroying them with precision while sparing most healthy tissue.
"We can deliver a high radiation dose to that specific area and maintain it within only one to two millimeters," said Daryl Eber, MD, a diagnostic radiologist and nuclear medicine doctor in Miami. He owns and operates3T Radiology & Research, a private practice that's acquiring the technology to start offering theranostics to patients.
What Does Treatment Look Like?
A lot of the work behind theranostics happens in advance, with extensive testing to find out if the treatment is a good match for the patient.Something called dosimetry helps personalize the dose for each patient – enough to destroy cancer cells, but not too much to damage healthy tissue, Eber said.
A doctor may recommendgenetic or molecular tests, or a PET scan to screen for PSMA on cancerous lesions, to look for receptors or genetic mutations that the treatment could target.
"Then the actual treatment itself is pretty easy," Eber said.
First, a diagnostic radiotracer is injected into your arm via an IV infusion, followed by a therapeutic radiotracer through a different IV a short time later. A PET scan helps make the lesions visible during both sessions, tracking progress as they're treated.
This process may be repeated up to six times, with about six weeks between treatments. After each cycle, patients return home with instructions to avoid too much close contact with family, as there's still a radioactive substance in their body.
"They have to be very careful being around other people, including loved ones," Eber said."They might have to sleep in a separate room. They might have to use different linen. They may have to use different silverware and wash it separately. Use a separate bathroom." They must also drink plenty of water to help flush out any remaining radioactive material.
After the final cycle, a patient will go back to get another scan with the diagnostic radiotracer to see how the treatment worked.
'See What You Treat and Treat What You See'
Theranostics can work onseveral cancers, but its biggest impact so far is on prostate cancer, especially in advanced stages. The radioactive drug can travel through the body and bind to cancer-specific markers, delivering a direct hit to tumors to wherever they've spread.
"The best use is stage four metastatic," said Jeremie Calais, MD, PhD, who heads the Clinical Research Program of the Ahmanson Translational Theranostics Divisionat UCLA. When the cancer has spread and surgery is no longer an option, theranostics delivers radiation body-wide, targeting cancer at multiple sites."The central paradigm is'see what you treat and treat what you see.'"
Success stories of theranostics against aggressive prostate cancer started to come out of Europe around 2015."In some patients, you were able to see dramatic, deep responses that were unseen before," Calais said."Patients who were dying within six months, their lives would extend to maybe two years while having a great quality of life."
Eber has witnessed first-hand the power of theranostics in treating a patient with stage IV cancer."Before the treatment, I saw cancer lesions light up on scans," he said."On their follow-up six months later and after treatment, there was regression and I didn't see the same lesions."
The Research Pipeline
These days, theranostics is"completely exploding and growing," said Calais, and many clinical trials are underway.
In 2022, Pluvicto became the first theranostic to receive FDA approval for the treatment ofadvanced metastatic prostate cancer. (Additional indications were added earlier this year.) With Pluvicto, the diagnostic agent gallium-68 gozetotide identifies cancer cells, and lutetium-177 emits beta radiation to kill them.
The following year, Weill Cornell researchers led aphase I trial for a second prostate cancer theranostic treatment. It included patients with progressive metastatic castrate-resistant prostate cancer (a type that keeps growing despite hormone therapy) who were given a single dose of a radiopharmaceutical with actinium-225 attached to it.
Unlike beta emitters like lutetium-177, actinium-225 emits high-energy alpha particles, which are4,000 times more potent and have a shorter delivery range than beta particles. Meaning: They hit cancer cells much more powerfully, and with even less risk of damage to surrounding tissue.
Another clinical trial isACCEL, which is using actinium-225 combined with PSMA-targeting proteins that can bind to cancer cells.
Newer theranostics treatments are also available for thyroid cancer, which has been treated with iodine-131 since 1951:Sorafenib (Nexavar),which received FDA approval in 2005, andlenvatinib (Lenvima), approved in 2019.
"One of the things that makes the theranostics field so exciting is that developments are happening constantly," said James Kelly, PhD, chief of radiopharmaceutical sciences at Weill Cornell Medicine.Kelly's lab is working on developing new radiopharmaceuticals and finding new molecular targets for cancer and neurodegenerative diseases."It really is at the nexus of nuclear physics, biochemistry, chemistry, and medicine."
Who Would Benefit Most From Theranostics?
Traditional prostate cancer treatments include radical prostatectomy (removing the whole gland), focal surgery to ablate the tumor, hormonal drugs (which decrease the level of androgens to prevent the tumor from growing), or chemotherapy if the cancer has spread.
Each has side effects. In radical prostatectomy, for instance, the surgeon could"hit the pudendal nerve, which would then cause erectile dysfunction," said Eber. Other risks include"damage to some of the valves of the urethra," he added, which can cause scarring, narrowing, and inflammation, leading to persistent, and sometimes severe, pain.
In some cases, patients could have better outcomes with theranostics, which delivers the most benefits for patients with metastatic prostate cancer, along with those who have thyroid cancer and neuroendocrine tumors. For anyone interested in exploring this therapy option, the first step is to consult with oncologists and nuclear medicine specialists, and try to find an advanced cancer center or academic institution.
Theranostics has side effects, too, though most aren't severe. Patients may have fatigue, nausea, vomiting, bone pain, and dry mouth. Radiation doses must be monitored closely, as excess radiation can damage healthy organs.
The biggest challenge right now is accessibility. At $40,000 per treatment, a standard six-cycle course may be cost prohibitive for patients without insurance or whose insurance won't pay for it. While it's generally covered by insurance and Medicare, Medicaid coverage varies by state.
Even harder is finding a facility that offers the treatment. And researchers are struggling to find enough actinium-225, an isotope in high demand and low supply, according to the U.S. Department of Energy Isotope Program.
"Alpha emitters have not historically been as readily accessible as beta emitters," said Kelly."Securing enough supply to support all these studies has been a challenge for the field over a number of years."
And promising as theranostics is, it isn't a magic bullet against prostate cancer, either. Sometimes, the disease doesn't express enough targets to use the approach – in which case, traditional chemotherapy may be the best course of action.
It's also worth remembering that"this treatment is not a cure," said Calais."It is effective, but still, many patients relapse and progress ultimately."
