Letrozole
| Evidence Level: L5 | Predicted Indications: 4 |
Table of Contents
Letrozole: Nipple carcinoma
One-Sentence Summary
Letrozole is an aromatase inhibitor that blocks estrogen production. The TxGNN model predicts it may be useful for nipple carcinoma, but the evidence is thin: no clinical trials are registered, and the 8 publications found are mostly case reports. The evidence level is L5.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Not recorded in the local data |
| Predicted New Indication | Nipple carcinoma |
| TxGNN Prediction Score | 0.9976 |
| Evidence Level | L5 |
| India Market Status | Listed in a compiled Indian medicine price dataset (at least 20) – CDSCO approval status is not included in this data |
| Number of Listed Products | at least 20 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Detailed mechanism of action data is not available in the data compiled for this report. Letrozole belongs to the aromatase inhibitor class, which lowers estrogen levels. Nipple carcinoma is a breast cancer subtype, so hormone-receptor-positive disease could plausibly respond to aromatase inhibition.
This link is only a hypothesis. No study tests letrozole in nipple carcinoma. The related literature consists of case reports and a single report of neoadjuvant endocrine therapy in neuroendocrine carcinoma of the breast, which is a different condition. These do not establish that letrozole works for nipple carcinoma.
Clinical Trial Evidence
Currently no related clinical trials registered.
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 33120755 | 2020 | Cohort / case report | Medicine | Neoadjuvant endocrine therapy in poorly differentiated neuroendocrine carcinoma of the breast; a related but different condition |
| 41607681 | 2026 | Case report | Clinical Case Reports | Solid papillary carcinoma in situ arising in the nipple, with literature review |
| 34495428 | 2021 | Case report | Surgical Case Reports | Accessory breast cancer in the inframammary region |
| 40395253 | 2025 | Case report | Cureus | Axillary recurrence in breast cancer with bloody nipple discharge |
| 42040393 | 2026 | Case report | Clinical Case Reports | Tall cell carcinoma of the breast with reverse polarity and IDH1 mutation |
| 39682607 | 2024 | Case report | Diagnostics (Basel) | Metastatic infra-mammary accessory breast cancer with ipsilateral breast cancer |
| 42305961 | 2026 | Case report | Frontiers in Medicine | Synchronous accessory breast cancer, papillary thyroid carcinoma and nasal papilloma |
| 42416948 | 2026 | Case report | Cureus | Ultrasound findings in florid lobular carcinoma in situ |
India Market Information
At least 20 valid single-ingredient licences are listed, and the list may be partial. Main examples:
| Authorization Number | Product Name | Dosage Form | Approved Indication |
|---|---|---|---|
| Registration No. 52386 | Canctroz 2.5mg Tablet | Strip of 10 tablets | Not stated |
| Registration No. 123893 | Letor Tablet | Strip of 14 tablets | Not stated |
| Registration No. 126257 | Letshil 2.5mg Tablet | Strip of 10 tablets | Not stated |
| Registration No. 128156 | Letrocyt 2.5mg Tablet | Strip of 5 tablets | Not stated |
| Registration No. 125294 | Lutrazole Tablet | Strip of 5 tablets | Not stated |
Cytotoxicity
| Item | Content |
|---|---|
| Cytotoxicity Classification | Targeted hormonal therapy (aromatase inhibitor), not a conventional cytotoxic agent |
| Myelosuppression Risk | Please refer to the package insert warnings and precautions |
| Emetogenicity Classification | Please refer to the package insert warnings and precautions |
| Monitoring Items | Please refer to the package insert warnings and precautions |
| Handling Protection | Please refer to the package insert warnings and precautions |
Safety Considerations
- Drug Interactions: 259 interactions are recorded. The only one graded Moderate is aprepitant. Others, such as calcitriol, glimepiride, lansoprazole, metformin, omeprazole and simvastatin, have no severity grade.
For warnings and contraindications, please refer to the package insert.
Conclusion and Next Steps
Decision: Hold
Rationale: No study tests letrozole in nipple carcinoma, and the available literature is limited to case reports of related conditions. The prediction rests on the model score and a plausible mechanism, so the evidence level is L5.
To proceed, the following is needed:
- Studies that directly test letrozole in nipple carcinoma, including hormone receptor status of the tumours
- Detailed mechanism of action data
- Package insert warnings and contraindications
- Safety review for patients with liver impairment or low bone density
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.