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LETR

Cancer Type: Breast  Intent: Palliative
Regimen Category: Evidence-Informed
Funding:
ODB Limited Use
  • letrozole - Treatment of metastatic breast cancer in hormone receptor positive postmenopausal women
A - Regimen Name

 

LETR Regimen
Letrozole

 

 

Disease Site
Breast

 

 

Intent
Palliative

 

 

Regimen Category
Evidence-Informed :

Regimen is considered appropriate as part of the standard care of patients; meaningfully improves outcomes (survival, quality of life), tolerability or costs compared to alternatives (recommended by the Disease Site Team and national consensus body e.g. pan-Canadian Oncology Drug Review, pCODR).  Recommendation is based on an appropriately conducted phase III clinical trial relevant to the Canadian context OR (where phase III trials are not feasible) an appropriately sized phase II trial. Regimens where one or more drugs are not approved by Health Canada for any indication will be identified under Rationale and Use.

 

 

Rationale and Uses

First-line treatment of hormone-receptor positive advanced breast cancer in postmenopausal women
or
Hormonal treatment of advanced/metastatic hormone-receptor positive breast cancer after relapse or disease progression, in women with natural or artificially-induced postmenopausal endocrine status, who have previously been treated with anti-estrogens

 

 

Supplementary Public Funding

letrozole
ODB Limited Use (letrozole - Treatment of metastatic breast cancer in hormone receptor positive postmenopausal women) (ODB Formulary)
 

 

 
B - Drug Regimen

 

letrozole
 
2.5 mgPODaily

(Outpatient prescription in 2.5mg tablets)

 

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C - Cycle Frequency

 

CONTINUOUS TREATMENT

Until evidence of disease progression or unacceptable toxicity

 

 
D - Premedication and Supportive Measures
 
Antiemetic Regimen:

Not applicable

Other Supportive Care:

Consider calcium and vitamin D supplements in patients with advanced breast cancer who have no history of hypercalcemia. For more information about bone health via dietary and lifestyle measures, see pamphlet on Bone Health in Postmenopausal Women
 
E - Dose Modifications

Dosage with toxicity

 

Dosage in myelosuppression: No dosage adjustment required.

 

 

 

Hepatic Impairment

Hepatic Impairment
Dose
Mild to moderate

No dose adjustment needed, although exposure may ↑ by 37%

Severe
No data. Monitor patients closely and consider dose modification.
 

Renal Impairment

Creatinine clearance

Dose
≥ 10 mL/min
No dose adjustment needed
< 10 mL/min
No data. Consider potential benefit-risk carefully.
 
F - Adverse Effects
Refer to letrozole drug monograph(s) for additional details of adverse effects
 

Most Common Side Effects 

Less Common Side Effects, but may be
Severe or Life-Threatening

  • Estrogen withdrawal symptoms
  • Fatigue
  • Headache, musculoskeletal pain
  • Edema
  • ↑ Cholesterol
  • Dizziness
  • Constipation
  • Nausea / vomiting
  • Osteoporosis, fracture
  • Arrhythmia
  • Rash
  • Arterial thromboembolism
  • Venous thromboembolism
  • Cardiotoxicity
  • Cataracts
  • Hypersensitivity
 
G - Interactions
Refer to letrozole drug monograph(s) for additional details
 
H - Drug Administration and Special Precautions
Refer to letrozole drug monograph(s) for additional details
 
I - Recommended Clinical Monitoring

Treating physicians may decide to monitor more or less frequently for individual patients but should always consider recommendations from the product monograph.

Recommended Clinical Monitoring

  • Bone mineral density; baseline and regular
  • LH, FSH and/or estradiol levels in patients whose menopausal status is unclear or who become amenorrheic after chemotherapy; before starting letrozole and regularly during the first 6 months of treatment. Only confirmed postmenopausal patients should receive letrozole.
  • Serum cholesterol and lipids evaluation; baseline and regular
  • Clinical assessment of fatigue, estrogen withdrawal symptoms, musculoskeletal, cardiovascular, thromboembolism, GI and GU effects, ophthalmic; at each visit
  • Grade toxicity using the current NCI-CTCAE (Common Terminology Criteria for Adverse Events) version


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J - Administrative Information
Outpatient prescription for home administration
 
 
 
K - References

Dombernowsky P, Smith I, Falkson G, Leonard R et al. Letrozole, a new oral aromatase inhibitor for advanced breast cancer: double-blind randomized trial showing a dose effect and improved efficacy and tolerability compared with megestrol acetate. J Clin Oncol 1998;16:453-61.

Gershanovich M, Chaudri HA, Campos D, et al. Letrozole, a new oral aromatase inhibitor: randomized trial comparing 2.5 mg daily, 0.5 mg daily and aminoglutethimide in postmenopausal women with advanced breast cancer. Ann Oncol 1998;9:639-45.

Mouridsen H, Gershanovich M, Sun Y, Pérex-Carrion R et al. Superior efficacy of letrozole (femara) versus tamoxifen as first-line therapy for postmenopausal women with advanced breast cancer: results of a phase III study of the international letrozole breast cancer group. J Clin Oncol 2001;19:2596-606.

October 2017 removed subsite (already under intent)

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M - Disclaimer

Regimen Abstracts
A Regimen Abstract is an abbreviated version of a Regimen Monograph and contains only top level information on usage, dosing, schedule, cycle length and special notes (if available). It is intended for healthcare providers and is to be used for informational purposes only. It is not intended to constitute or be a substitute for medical advice, and all uses of the Regimen Abstract are subject to clinical judgment. Such information is provided on an “as-is” basis, without any representation, warranty, or condition, whether express, or implied, statutory or otherwise, as to the information’s quality, accuracy, currency, completeness, or reliability, and Cancer Care Ontario disclaims all liability for the use of this information, and for any claims, actions, demands or suits that arise from such use.
Information in regimen abstracts is accurate to the extent of the ST-QBP regimen master listings, and has not undergone the full review process of a regimen monograph.  Full regimen monographs will be published for each ST-QBP regimen as they are developed.
Regimen Monographs
Refer to the New Drug Funding Program or Ontario Public Drug Programs websites for the most up-to-date public funding information.
The information set out in the drug monographs, regimen monographs, appendices and symptom management information (for health professionals) contained in the Drug Formulary (the "Formulary") is intended for healthcare providers and is to be used for informational purposes only. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects of a particular drug, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for a given condition. The information in the Formulary is not intended to constitute or be a substitute for medical advice and should not be relied upon in any such regard. All uses of the Formulary are subject to clinical judgment and actual prescribing patterns may not follow the information provided in the Formulary.
The format and content of the drug monographs, regimen monographs, appendices and symptom management information contained in the Formulary will change as they are reviewed and revised on a periodic basis. The date of last revision will be visible on each page of the monograph and regimen. Since standards of usage are constantly evolving, it is advised that the Formulary not be used as the sole source of information. It is strongly recommended that original references or product monograph be consulted prior to using a chemotherapy regimen for the first time.
Some Formulary documents, such as the medication information sheets, regimen information sheets and symptom management information (for patients), are intended for patients. Patients should always consult with their healthcare provider if they have questions regarding any information set out in the Formulary documents.
While care has been taken in the preparation of the information contained in the Formulary, such information is provided on an “as-is” basis, without any representation, warranty, or condition, whether express, or implied, statutory or otherwise, as to the information’s quality, accuracy, currency, completeness, or reliability.
CCO and the Formulary’s content providers shall have no liability, whether direct, indirect, consequential, contingent, special, or incidental, related to or arising from the information in the Formulary or its use thereof, whether based on breach of contract or tort (including negligence), and even if advised of the possibility thereof. Anyone using the information in the Formulary does so at his or her own risk, and by using such information, agrees to indemnify CCO and its content providers from any and all liability, loss, damages, costs and expenses (including legal fees and expenses) arising from such person’s use of the information in the Formulary.