What is the role of adjuvant (additional) therapy?

From the Guidelines

Adjuvant therapy should be considered for patients with early-stage breast cancer, particularly those with HR-positive, HER2-negative tumors, to reduce the risk of cancer recurrence, as recommended by the NCCN guidelines 1. The decision to administer adjuvant therapy depends on various factors, including cancer type, stage, and patient-specific factors like age and overall health.

• For patients with HR-positive, HER2-negative breast cancer, adjuvant endocrine therapy is recommended to reduce the risk of recurrence, and adjuvant chemotherapy may be considered for those at high risk of distant recurrence despite adjuvant endocrine therapy 1.
• The use of adjuvant chemotherapy in elderly patients with colon cancer has been shown to be effective in reducing mortality, with studies demonstrating that age alone should not exclude patients from consideration for adjuvant therapy 1.
• However, the decision to use adjuvant therapy in elderly patients should be made on a case-by-case basis, taking into account the patient's overall health, comorbidities, and potential toxicity of treatment.
• Common adjuvant chemotherapy regimens include AC-T for breast cancer, FOLFOX for colon cancer, and cisplatin-based combinations for lung cancer, while hormone therapies like tamoxifen or aromatase inhibitors are used for hormone-receptor-positive breast cancers.
• Radiation therapy is often given daily over 3-6 weeks following breast-conserving surgery or for rectal cancers, and targeted therapy or immunotherapy may also be considered as adjuvant treatment options.
• The goal of adjuvant therapy is to eliminate any remaining microscopic cancer cells, thereby reducing the risk of cancer recurrence and improving survival rates.

From the FDA Drug Label

The Early Breast Cancer Trialists’ Collaborative Group (EBCTCG) conducted worldwide overviews of systemic adjuvant therapy for early breast cancer in 1985,1990, and again in 1995. In 1998,10 year outcome data were reported for 36,689 women in 55 randomized trials of adjuvant tamoxifen using doses of 20 to 40 mg/day for 1 to 5+ years Among women with ER positive or unknown breast cancer and positive nodes who received about 5 years of treatment, overall survival at 10 years was 61.4% for tamoxifen vs. 50.5% for control (logrank 2p < 0.00001). A multicenter, open-label, randomized trial (TAX316) evaluated the efficacy and safety of Docetaxel Injection for the adjuvant treatment of patients with axillary-node-positive breast cancer and no evidence of distant metastatic disease In study TAX316, the docetaxel-containing combination regimen TAC showed significantly longer disease-free survival (DFS) than FAC (hazard ratio=0.74; 2-sided 95% CI=0.60,0.92, stratified log rank p=0. 0047).

Adjuvant therapy with tamoxifen or docetaxel has been shown to be effective in the treatment of early breast cancer.

• Tamoxifen has been shown to improve overall survival and reduce the risk of recurrence in women with ER positive or unknown breast cancer.
• Docetaxel has been shown to improve disease-free survival and overall survival in patients with axillary-node-positive breast cancer when used in combination with doxorubicin and cyclophosphamide. The use of adjuvant therapy should be determined on a case-by-case basis, taking into account the individual patient's risk factors and medical history 2 3.

From the Research

Adjuvant Therapy Overview

• Adjuvant therapy is a treatment given in addition to the primary treatment to prevent the recurrence of cancer.
• Studies have shown that adjuvant therapy can improve disease-free survival and overall survival in patients with breast cancer 4, 5.

Types of Adjuvant Therapy

• Chemotherapy: Doxorubicin plus cyclophosphamide (AC) is a standard adjuvant chemotherapy regimen 4.
• Targeted therapy: Trastuzumab is a targeted therapy used in combination with chemotherapy for HER2-positive breast cancer 6, 5, 7, 8.
• Hormone therapy: Tamoxifen is used for patients with hormone receptor-positive disease 4.

Efficacy of Adjuvant Therapy

• A study comparing doxorubicin plus cyclophosphamide with docetaxel plus cyclophosphamide as adjuvant therapy for operable breast cancer found that docetaxel plus cyclophosphamide was associated with a superior disease-free survival rate 4.
• Another study found that the addition of trastuzumab to a non-anthracycline regimen, docetaxel plus cyclophosphamide, improved disease-free survival in patients with HER2-amplified early stage breast cancer 5.
• A phase II study of pegylated liposomal doxorubicin, docetaxel, and trastuzumab as neoadjuvant treatment for HER2-positive breast cancer found a high pathological complete response rate 7.

Safety and Tolerability

• Adjuvant therapy can be associated with toxicities such as myalgia, arthralgia, edema, and febrile neutropenia 4.
• The use of liposomal doxorubicin can reduce cardiotoxicity compared to traditional anthracyclines 7, 8.
• Metformin has been added to adjuvant therapy regimens to improve activity and reduce toxicity 8.