Am I a Candidate for Radiopharmaceutical Therapy?

Overview

For many patients who learn that a radiopharmaceutical therapy might be an option for their cancer care journey, the first question is rarely about mechanism or side effects. It’s a simpler, more urgent one: Is this even for me?

Radiopharmaceutical therapies, including PLUVICTO® (lutetium Lu-177 PSMA-617), LUTATHERA® (lutetium Lu-177 DOTATATE), Xofigo® (radium Ra-223 dichloride), and radioiodine (I-131), are still relatively unfamiliar to many patients, and the path to treatment isn’t always easily explained by referring physicians. But according to Dr. Michael A. Morris, MD, MS, DABR, DABNM, DCI, Nuclear Oncologist and Co-Founder of United Theranostics, the answer to that question is more reassuring than most patients expect.

“Most patients are candidates,” Dr. Morris says. “The only times we have a difficult time treating a patient is if they don’t have uptake of the target.”

What Determines Radiopharmaceutical Therapy Eligibility

Unlike traditional chemotherapy, which works by broadly attacking rapidly dividing cells, radiopharmaceutical therapies work by seeking out a specific molecular target expressed on cancer cells. A radioisotope is attached to a molecule that binds to that target, delivering particle-emission energy directly to the tumor while limiting exposure to surrounding tissue.

This targeting mechanism is a large part of what determines whether a patient qualifies. While other considerations certainly can impact eligibility, such as how advanced a patient’s disease is, how many prior treatments they’ve had, organ function, etc., Dr. Morris has found that the number one question is usually this: does the patient’s cancer express the right molecular target?

Before any treatment begins, this question is answered through a non-invasive diagnostic scan (typically a PET/CT scan).

“Not only do we know where our treatments are going because we can image them,” explains Dr. Morris, “but a step before that, we actually do a targeted scan for that particular cancer and confirm that the cancer expresses the target for the treatment that we are going to give.”

This is the core of theranostics: the same biological feature that makes a cancer visible on a diagnostic scan is also the feature the therapy is designed to exploit in its attack.

Who Qualifies for Radiopharmaceutical Therapy: Eligibility by Cancer Type

Prostate Cancer: PLUVICTO® and Xofigo®

For patients with prostate cancer, two radiopharmaceutical options may be available, depending on the extent and location of the disease.

PLUVICTO® targets a protein called PSMA (prostate-specific membrane antigen), which is highly expressed in most prostate cancers. Eligibility is confirmed through a PSMA PET/CT scan. When PLUVICTO® was first approved by the FDA in 2022, it was indicated only for patients who had already received both hormonal therapy and chemotherapy. That label has since changed. Today, PLUVICTO® is available to patients who have progressed on hormonal therapy, before chemotherapy is required.

Dr. Morris was direct about what this shift means in practice. “As soon as patients have recurrent disease that is detectable with the PSMA PET/CT,” he says, “that’s when I would start to consider PLUVICTO®.” He added that patients who have not yet exhausted their treatment options tend to respond better. “I would encourage patients not to wait, but to come in sooner and explore their options.”

For patients with prostate cancer that has spread to the bone, Xofigo® may be an additional or alternative option. Rather than targeting a molecular protein, Xofigo® (radium Ra-223 dichloride) mimics calcium and is incorporated into areas of new bone formation around cancer cells, delivering alpha radiation locally. Patients with significant bone involvement and bone pain are often the best candidates.

Neuroendocrine Tumors: LUTATHERA®

For patients with neuroendocrine malignancies, LUTATHERA® (lutetium Lu-177 DOTATATE) has undergone a similar evolution in its labeled indication, and in a significant way. Eligibility is confirmed through a DOTATATE PET/CT scan, which detects somatostatin receptor expression on tumor cells.

When LUTATHERA® was first approved in 2018, it was initiated after patients had failed long-acting somatostatin analogs; the monthly injection-based therapies used to control the growth of some neuroendocrine tumors by switching off hormone signals. Incidentally, it was shortly after this approval that United Theranostics first opened its doors, allowing it to become one of the first clinics in the world to offer this therapy.

The evidence has since supported moving to LUTATHERA® much earlier. Based on data from the NETTER-2 trial, LUTATHERA® is now available as a first-line treatment for eligible patients with recurrent or non-resectable disease (unable to be removed via surgery).

“We’re very pleased that LUTATHERA®, together with long-acting somatostatin analogs, is now available as a first-line treatment for patients with neuroendocrine malignancies when surgery can no longer offer them a potential curative treatment,” Dr. Morris noted. As with prostate cancer, he emphasized that timing matters: patients who come in earlier, with less extensive disease burden, tend to have better treatment outcomes.

Thyroid Cancer: Radioiodine (I-131)

For patients with thyroid cancer, radioiodine (I-131) is the most established radiopharmaceutical therapy in use today. In fact, it has a clinical track record stretching back more than 80 years. Eligibility for this treatment is primarily determined by how much iodine the thyroid tissue and cancer cells take up through a cell surface protein called a sodium iodide symporter, assessed through an iodine uptake scan.

Unlike the other therapies discussed here, I-131 is typically initiated relatively soon after surgery, even in some patients who do not have detectable residual disease outside the thyroid. In patients with more extensive disease involving lymph nodes, lung, or bone, I-131 can offer curative-intent treatment with appropriate planning. Dr. Morris described it as a benchmark for what the field is working toward with newer agents: “Our goal is one day to achieve the similar results that we have with iodine-131, treating earlier and really offering patients long-term continued absence of disease recurrence.”

What If Part of the Disease Doesn’t Take Up the Target?

In some cases, most of a patient’s disease expresses the target, but isolated areas may not. This doesn’t necessarily disqualify a patient from radiopharmaceutical therapy. Those areas can often be addressed with complementary approaches such as focal external beam radiation, ablation, or other treatments, while the radiopharmaceutical handles systemic disease.

“If there is an area of disease or multi-area diseases that do not take up that treatment target, which we can detect on the non-invasive imaging, then those areas may require other types of treatments,” Dr. Morris explains. “As long as the patient has some target expression, they should be a candidate.”

The Role of the Referring Physician

Many patients first hear about radiopharmaceutical therapy from their oncologist or urologist, but referring physicians aren’t always certain when the ideal time to make that referral is, or whether the process will be complex for their office.

Dr. Morris was clear that the referral process at United Theranostics is designed to be straightforward. “As soon as a patient wants to be evaluated, they can just provide us with the patient’s information, their recent clinical notes, some historical information about their disease, and we’re happy to see the patient and work through getting the treatments approved and coordinating care.” Insurance authorization and prior approval are handled by United Theranostics, not the referring office.

He also emphasized the importance of early evaluation, not just for patient outcomes, but for preserving options. “I would not wait to come in to be evaluated. I would come in sooner, and then even if we decide the timing isn’t right yet, that will help to make sure they don’t come too late.”

What’s on the Horizon

The label changes to PLUVICTO® and LUTATHERA® over the past few years reflect a broader pattern: as post-market research accumulates, radiopharmaceutical therapies continue to move earlier into the treatment sequence. Research is currently underway examining PLUVICTO® in earlier-stage prostate cancer, including adjuvant use alongside surgery and radiation for high-risk disease.

United Theranostics participates in more than 20 radiopharmaceutical clinical trials across various disease targets, offering patients access to emerging therapies not yet available through standard care. For patients who may not qualify under current approved indications, clinical trials may result in an additional path for consideration.

Talk to a Theranostics Specialist

If you or someone you love has been diagnosed with prostate cancer, a neuroendocrine tumor, thyroid cancer, or is looking for a clinical trial option, or is looking for a clinical trial option, a consultation with a Nuclear Oncologist at United Theranostics can help determine whether radiopharmaceutical therapy is an option.

If your oncologist, urologist, or endocrinologist has not yet discussed radiopharmaceutical therapy with you, consider asking, or reaching out to United Theranostics directly to schedule a consultation.