Cancer treatment has evolved remarkably advanced with nuclear medicine. Radioactive isotopes, also known as radioisotopes or radiopharmaceuticals, play a vital role in both diagnosis and therapy. The choice of isotope depends on cancer type, tumour location, and treatment goal — whether curative or palliative.
Understanding Isotopes and Radioisotopes
Isotopes are atoms of the same element with different neutron counts. Radioactive isotopes (radioisotopes) naturally decay and emit alpha, beta, or gamma radiation. In oncology, this radiation destroys cancer cell DNA while sparing healthy tissue as much as possible.
How Radioisotopes Are Used in Cancer Therapy
Two major approaches dominate:
- Brachytherapy – temporary or permanent placement of sealed radioactive sources inside or near the tumour.
- Targeted Radionuclide Therapy (TRT) – systemic administration of unsealed radioisotopes that selectively accumulate in cancer cells.
Most Commonly Used Isotopes for Cancer Treatment in 2025
Iodine-131 (I-131
Primary use: Thyroid cancer and hyperthyroidism-related tumours Administration: Oral capsule or liquid Mechanism: Beta emitter selectively taken up by thyroid tissue Success rate: >90% cure rate in early-stage thyroid cancer
Radium-223 (Ra-223) – Xofigo
Primary use: Castration-resistant prostate cancer with bone metastases Mechanism: Alpha emitter that mimics calcium and targets bone lesions Benefit: Improves overall survival and reduces skeletal-related events
Yttrium-90 (Y-90)
Primary use: Liver cancer (HCC) and liver metastases via radioembolization (SIRT) Administration: Microspheres injected into hepatic artery Advantage: Delivers extremely high local radiation (up to 1000+ Gy) with minimal systemic exposure
Lutetium-177 (Lu-177) – Current Gold Standard in Theranostics
Primary uses:
- Neuroendocrine tumours (Lu-177 DOTATATE – Lutathera)
- Metastatic castration-resistant prostate cancer (Lu-177 PSMA-617 – Pluvicto) Mechanism: Beta emitter linked to somatostatin analogues or PSMA ligands Remark: First FDA and CDSCO-approved theranostic pair (diagnosis with Ga-68, therapy with Lu-177)
Cobalt-60
Still widely used in teletherapy machines (external beam radiotherapy) in low- and middle-income countries because of long half-life (5.27 years) and high-energy gamma rays.
Iridium-192
High-dose-rate (HDR) brachytherapy for cervical, prostate, breast, and head & neck cancers Advantage: Small source size allows precise dose delivery
Phosphorus-32
Rarely used now; earlier for polycythemia vera and malignant pleural/peritoneal effusions
Advantages of Radioisotope Therapy
- Highly targeted – “seek and destroy” approach
- Outpatient or short-stay procedure in most cases
- Fewer side effects compared to traditional chemotherapy
- Can treat multifocal and metastatic disease
- Improves quality of life and survival in advanced stages
Risks and Side Effects
- Temporary fatigue, nausea, dry mouth (xerostomia)
- Bone marrow suppression (manageable with dose adjustment)
- Rare secondary malignancies
- Radiation safety precautions for 3–7 days after therapy
Real-Life Impact in India (2025 Scenario)
A 62-year-old patient from Bengaluru with metastatic prostate cancer and multiple bone metastases received six cycles of Lu-177 PSMA therapy at HCG Cancer Centre. PSA dropped from 280 to <0.1 ng/mL, pain disappeared, and he resumed normal activities within months — a result previously unimaginable.
Similarly, hundreds of neuroendocrine tumour patients across Tata Memorial Mumbai, AIIMS Delhi, and Apollo Proton Centre Chennai are achieving long-term remission with Lu-177 DOTATATE.
Expert Recommendation
Dr. Raghunadharao D., Senior Medical Oncologist & Nuclear Medicine Specialist, says: “Theranostics using Lu-177 and emerging alpha emitters like Actinium-225 will dominate metastatic cancer management in the coming decade. Early molecular imaging and correct patient selection are key to success.”
Can Radioactive Isotopes Help Manage Diabetes Complications in Cancer Patients?
Yes. Many cancer patients develop steroid-induced or new-onset diabetes during treatment. At TapHealth, our dedicated diabetes reversal and management program helps cancer survivors and active patients maintain optimal glucose control through precision nutrition, remote monitoring and GLP-1-based therapies — ensuring cancer therapy is never compromised due to uncontrolled sugar levels.
Radioisotope therapy continues to revolutionize cancer care with ever-increasing precision and safety. Staying informed and consulting a qualified nuclear medicine specialist remains the best step toward personalized, effective treatment.
