Recommended Number of Lutetium-177 (LU-177) Infusions for Cancer Treatment
The recommended number of Lutetium-177 (LU-177) infusions is 3-5 cycles for neuroendocrine tumors, 6 cycles for prostate cancer, with cycles administered every 6-12 weeks depending on the specific indication. 1, 2
Treatment Regimens by Cancer Type
For Neuroendocrine Tumors (NETs)
- Dosage: 5.55-7.4 GBq (150-200 mCi) per cycle
- Number of cycles: 3-5 cycles
- Interval between cycles: 6-12 weeks 1, 2
For Prostate Cancer (PSMA-positive mCRPC)
- Dosage: 7.4 GBq (200 mCi) per cycle
- Number of cycles: Up to 6 cycles
- Interval between cycles: Every 6 weeks 3
Factors Affecting Treatment Cycles
The number of cycles may be adjusted based on:
- Treatment response: Continued until disease progression or unacceptable toxicity 3
- Patient-specific factors:
- Dosimetry results: Individual patient dosimetry may guide treatment to avoid exceeding the 2 Gy threshold for red bone marrow 2
Retreatment Considerations
- Retreatment with LU-177 is possible after disease progression following initial treatment
- Minimum interval of 6 months after completion of initial treatment is recommended
- Retreatment typically consists of 1-2 additional cycles 2
- Extended therapy beyond standard protocols has shown favorable outcomes in selected patients 4
Monitoring During Treatment
- Complete blood count every 2-4 weeks after treatment
- Renal and liver function tests before subsequent cycles
- Whole-body imaging following each cycle to document radiopharmaceutical distribution 2
Special Considerations for Compromised Patients
For patients with reduced renal function or compromised bone marrow:
- Administered activity may be reduced
- Treatment cycles should be individualized
- Consider nephrourology consultation
- Ensure extensive hydration (2-3L fluid intake if clinically appropriate)
- Consider diuretics in case of dilated renal pelvis and delayed outflow 1, 2
Safety Profile of Extended Treatment
Recent evidence suggests that extended therapy with LU-177 beyond 6 cycles may be safe without increased grade 3-4 toxicity in selected patients. This can be administered either as continuous treatment or as a rechallenge after a treatment break 4.
The decision to extend treatment beyond the standard protocol should be based on:
In summary, while standard protocols recommend 3-5 cycles for NETs and 6 cycles for prostate cancer, treatment should be monitored and adjusted based on response and toxicity, with the possibility of retreatment or extended therapy in appropriate clinical scenarios.