Last reviewed by Dr. Dharmender Malik on 7 May 2026. Reflects published evidence as of the review date and FMRI institutional protocol.
"What is the success rate of PRRT?" is the first question almost every patient and family asks in the consultation room. It is the right question, and it deserves a careful answer — not a marketing one. The honest answer is layered: PRRT works very well in the right patients, the response is durable, and it is one of the most well-established radioligand therapies in nuclear medicine. But "success rate" depends on what you mean by success, which patients you measure it in, and what number you compare it against. This article unpacks all three.
Peptide Receptor Radionuclide Therapy — PRRT — uses a small peptide called DOTATATE, paired with the radioactive isotope Lutetium-177, to find and treat somatostatin-receptor-positive neuroendocrine tumours (NETs). The therapy received FDA approval in January 2018, marketed as Lutathera, after the pivotal NETTER-1 trial demonstrated meaningful improvements in progression-free survival and quality of life over standard care.[1] At FMRI Gurgaon, we have been performing PRRT for more than a decade, and we run one of the larger institutional NET-treatment volumes in India.
What "success" means in metastatic NET
Most NETs treated with PRRT are metastatic — the cancer has spread beyond its original site, most commonly to the liver, lymph nodes, or bone. PRRT is generally not curative in this setting. Saying that aloud is part of every consultation we have. What PRRT can do — reliably, in the right patients — is shrink or stabilise tumours, reduce hormonal symptoms (flushing, diarrhoea, carcinoid syndrome), and meaningfully extend the time before disease progression.
So when the literature reports a "PRRT success rate", it is typically measuring one of three things, and they do not mean the same thing:
- Objective tumour response (RECIST): measurable shrinkage on scans. In NETTER-1, approximately 18% of patients on Lu-177 DOTATATE plus standard-care octreotide had an objective response, compared with 3% on octreotide alone.[1]
- Disease control rate: response plus stable disease. This is the figure that matters most clinically, because in slow-growing NETs, "stable" is often as good as "smaller". Disease control in published Lu-177 DOTATATE series is typically reported between 65% and 80%.[2]
- Progression-free survival (PFS): how long before the disease starts growing again. NETTER-1 reported median PFS of approximately 28 months on Lu-177 DOTATATE plus octreotide, compared with about 8 months on octreotide alone. That difference — twenty months of additional disease control on average — is what makes PRRT the standard of care in midgut NETs.
The honest framing we use in clinic
"You will probably not be cured. Most patients on PRRT will have meaningful tumour shrinkage or stability that lasts two to four years, with substantial improvement in symptoms and quality of life. A smaller subset get longer benefit. A small minority do not respond at all. We will know which group you are in by your scans at cycles 2 and 4." That is the conversation, every time.
Who benefits most from PRRT
PRRT is not a treatment for every neuroendocrine tumour. The single most important predictor of response is somatostatin receptor (SSTR) expression on imaging — confirmed by a Ga-68 DOTATATE PET-CT scan before treatment is offered. Tumours that take up the tracer strongly are the ones that will absorb the therapeutic radioligand and respond. Tumours that do not are unlikely to benefit.
In our experience, the patients who do best on PRRT share several features:
- Strong, uniform SSTR expression across all measurable lesions on Ga-68 DOTATATE PET-CT
- Well-differentiated tumour grade — Ki-67 typically below 20% (Grade 1 or Grade 2 NET); higher-grade tumours can still respond but evidence is weaker
- Adequate organ function — preserved kidney function, adequate bone marrow reserve, manageable liver metastatic burden
- Manageable disease burden — patients with very extensive liver involvement may need additional liver-directed therapy alongside PRRT for best results
The therapy is offered for a range of NET sites: midgut (small bowel) carcinoids, pancreatic neuroendocrine tumours, paragangliomas, pheochromocytomas, thyroid medullary carcinoma in selected cases, and other gastroenteropancreatic NETs with proven SSTR expression. We assess each patient individually. PRRT is most strongly evidence-based for midgut NETs (the population studied in NETTER-1); for other sites, the evidence is supportive but the discussion about expected benefit is more individualised.
Figure 1. Lu-177 DOTATATE binds selectively to somatostatin receptors expressed on the surface of neuroendocrine tumour cells. The complex is internalised, and the beta radiation is delivered close to the cell's DNA — minimising damage to surrounding healthy tissue.
"Disease control of 65–80% sounds modest compared with curative surgery. In metastatic, slow-growing NET, it is one of the most meaningful numbers in modern oncology."
What our experience adds
FMRI has been performing PRRT for more than a decade, and we have one of the larger institutional NET volumes in India. Two things from our practice are worth mentioning here, because they are not visible in the trial literature alone:
First, intra-arterial Lu-177 DOTATATE for hepatic-dominant NET disease. We published a prospective comparison of intra-arterial versus standard intravenous administration in the British Journal of Radiology in 2021 — the intra-arterial route delivers higher tumour-to-background uptake in the liver in selected patients with predominantly hepatic disease.[3] It is not appropriate for every patient, and it requires interventional radiology partnership, but for the right candidate it is one of the few real innovations in PRRT delivery and we are one of a handful of centres in Asia performing it routinely.
Second, the Alpha PRRT pathway for non-responders. Patients whose disease progresses on standard Lu-177 DOTATATE — or who get an initial response that fades — are not without options. Actinium-225 DOTATATE, the alpha-emitter equivalent of standard PRRT, is offered at FMRI for selected patients who have run out of conventional options but remain candidates for further radioligand therapy. As with Alpha PSMA, it is offered under the framework of Article 37 of the Declaration of Helsinki, with full multidisciplinary review. The published evidence base is at an earlier stage than for Lu-PRRT, but the published series report meaningful response in selected post-Lu-progression patients.
The cost picture in India, honestly
Cost is part of every Indian PRRT consultation. PRRT in India is substantially less expensive than Lutathera in the United States or Europe, but it remains a significant out-of-pocket expense for most families paying privately. A complete four-cycle Lu-177 DOTATATE course at a tertiary centre runs into several lakh rupees, with variation based on body-weight-adjusted activity per cycle, hospital stay duration, pre-treatment Ga-68 DOTATATE PET-CT, and any additional supportive measures.
What we tell every family explicitly: do not start a course you cannot finish. A two-cycle PRRT course followed by financial discontinuation is rarely the right clinical move. If the family's resources will only stretch to two cycles, it is sometimes better to discuss alternative systemic therapy with the medical oncologist, work toward a financial plan, and revisit PRRT later. We would rather have that conversation at cycle zero than at cycle three.
Considering PRRT for yourself or a family member?
A consultation with Dr. Sen will review your imaging, prior treatment, and SSTR PET findings — and tell you honestly whether PRRT is indicated, what response is realistic, and what the complete course will cost.
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What side effects patients actually get
PRRT is one of the better-tolerated radiation-based cancer therapies. Most patients receive their cycle as outpatient day-care, return home the same day, and resume normal activities within 24 to 48 hours. The most common acute side effects are mild and predictable: nausea during the four-hour amino-acid co-infusion (used to protect the kidneys), transient fatigue for one to two weeks, and a small drop in blood counts that recovers between cycles.
Less common, but worth knowing about: renal toxicity — minimised by the amino-acid infusion protocol — and haematological toxicity, including a small long-term risk of treatment-related myelodysplasia or acute leukaemia (reported at roughly 2–3% in long-term follow-up of NETTER-1). For most patients with metastatic NET, the trade-off is acceptable, but we discuss it explicitly during consent.
A closing thought
PRRT is one of the most established and best-tolerated targeted therapies in nuclear medicine. For the right patient — somatostatin-receptor-positive, well-differentiated NET, adequate organ function, manageable disease burden — it offers something most metastatic cancer therapies cannot: a strong probability of meaningful disease control, often for years, with quality of life largely preserved. That is the honest "success rate".
For families considering PRRT, three things make the difference between a good experience and a frustrating one. First, the pre-treatment workup must include a recent Ga-68 DOTATATE PET-CT — without that scan, the decision to treat is being made in the dark. Second, the financial plan should cover the complete course, not a partial one. And third, the centre offering treatment should be transparent about what to expect: realistic response rates, side effect profile, and the next-line options if PRRT does not deliver the response you hoped for. We try to do all three, every time.
For patients & referring clinicians
Frequently asked questions
Q01
What is the success rate of PRRT?
In the pivotal NETTER-1 randomised controlled trial, 177Lu-DOTATATE (Lutathera) plus standard care produced an objective tumour response in approximately 18 percent of midgut neuroendocrine tumour patients, compared with 3 percent on standard care alone. Disease control (response plus stability) was achieved in roughly 65 to 80 percent of patients in published series. PRRT is not curative in the metastatic setting — the goal is durable disease control with quality of life preserved.
Q02
How long does PRRT response last?
In NETTER-1, median progression-free survival on Lu-177 DOTATATE plus octreotide was approximately 28 months, compared with 8 months on octreotide alone. Many responders derive benefit for two to four years before progression, and a smaller subset have stable disease beyond five years. Individual response duration varies with tumour grade, somatostatin receptor expression on imaging, and prior treatment history.
Q03
How much does PRRT cost in India?
PRRT cost in India is substantially lower than in the United States or Europe but remains a significant out-of-pocket expense for most families. The total cost of a four-cycle PRRT course at a tertiary centre like FMRI typically runs into several lakh rupees, with variation based on body-weight-adjusted activity, hospital stay requirements, and pre-treatment imaging. We discuss specific costs honestly in the consultation, before any cycle is scheduled, so families can plan a complete course rather than a partial one.
Q04
Is PRRT FDA approved?
Yes. Lu-177 DOTATATE, marketed as Lutathera, received FDA approval in January 2018 for the treatment of somatostatin receptor-positive gastroenteropancreatic neuroendocrine tumours. EMA approval followed in September 2017. The therapy administered at FMRI is the same molecule used in the NETTER-1 trial and in Lutathera.
Q05
What happens if PRRT stops working?
For patients who progress after standard PRRT, several options exist. Re-treatment with additional Lu-177 DOTATATE cycles can be considered if the initial response was good. Escalation to Alpha PRRT — Actinium-225 DOTATATE — is offered at FMRI for selected patients whose disease has progressed but who remain candidates for further radioligand therapy. Other systemic options including everolimus, sunitinib, and chemotherapy are discussed jointly with the medical oncologist.
Citations & references
Strosberg J, El-Haddad G, Wolin E, et al. Phase 3 trial of ¹⁷⁷Lu-Dotatate for midgut neuroendocrine tumors (NETTER-1).
N Engl J Med. 2017;376(2):125-135.
doi:10.1056/NEJMoa1607427Brabander T, van der Zwan WA, Teunissen JJM, et al. Long-term efficacy, survival, and safety of [¹⁷⁷Lu-DOTA⁰,Tyr³]octreotate in patients with gastroenteropancreatic and bronchial neuroendocrine tumors. Clin Cancer Res. 2017;23(16):4617-4624.
Sen IB, Thakral P, Malik D, et al. Intra-arterial versus intravenous administration of ¹⁷⁷Lu-DOTATATE in hepatic neuroendocrine tumour metastases — a comparative analysis. Br J Radiol. 2021. FMRI peer-reviewed publication.
U.S. Food and Drug Administration.
Lutathera (lutetium Lu 177 dotatate) approval for somatostatin receptor-positive gastroenteropancreatic neuroendocrine tumors. January 2018.
fda.govKratochwil C, Bruchertseifer F, Apostolidis C, et al. ²²⁵Ac-DOTATOC in neuroendocrine tumors — first-in-human dose finding and safety. Eur J Nucl Med Mol Imaging. 2014;41(10):2106-2119.
About the Author
Dr. Ishita B. Sen
MBBS · MD (Nuclear Medicine) · DNB · Post-doctoral Fellowship, Memorial Sloan Kettering Cancer Center, New York
Director & Chief of Nuclear Medicine at Fortis Memorial Research Institute. Co-founder of Theranostic Physicians Private Limited. Two decades in clinical nuclear medicine, with one of the larger Indian institutional experiences in PRRT for neuroendocrine tumours. Lead or co-author on multiple peer-reviewed publications including comparative work on intra-arterial Lu-177 DOTATATE.