Breast Cancer: A Contemporary Review of Risk Factors, Molecular Advances and Precision Therapy
Kunal I. Patil1, Junaid S. Shaikh2*
1Final Year Student, Shree Sureshdada Jain Institute of Pharmaceutical Education Research, Jamner, India.
2Assistant Professor, Department of Pharmaceutics,
Shree Sureshdada Jain Institute of Pharmaceutical Education Research, Jamner, Maharashtra, India.
*Corresponding Author E-mail: skjunaid.pharm@gmail.com
ABSTRACT:
Breast cancer is the most frequently diagnosed malignancy among women worldwide and remains a leading cause of cancer-related mortality¹. Recent global estimates indicate a rising incidence across both developed and developing nations, with disparities in survival linked to access to screening and treatment². Breast cancer is a biologically heterogeneous disease influenced by genetic susceptibility, hormonal exposure, environmental factors, and lifestyle behaviors³. Molecular characterization based on hormone receptors and HER2 expression has transformed clinical decision-making and enabled precision-based therapeutic approaches⁴. Standard management involves a multidisciplinary strategy incorporating surgery, radiotherapy, chemotherapy, endocrine therapy, targeted agents, and immunotherapy⁵⁻⁸. Innovations such as antibody–drug conjugates, CDK4/6 inhibitors, PARP inhibitors, immune checkpoint inhibitors, and genomic profiling have substantially improved patient outcomes⁶⁻⁹. Despite these advances, challenges including metastatic progression, therapeutic resistance, long-term toxicity, and healthcare inequities persist¹⁰. This comprehensive review discusses epidemiology, risk factors, molecular mechanisms, classification, clinical presentation, screening, diagnosis, staging, therapeutic strategies, complications, prevention, and emerging research directions in breast cancer management.
KEYWORDS: Breast cancer, BRCA mutation, HER2, Triple-negative breast cancer, Mammography, CDK4/6 inhibitors, Immunotherapy, Precision oncology, Antibody-drug conjugates, Screening.
1. INTRODUCTION:
Breast cancer originates from epithelial cells of the mammary ducts or lobules and is characterized by uncontrolled cellular proliferation and invasive potential³. It represents the most commonly diagnosed cancer globally, surpassing lung cancer in incidence¹. The biological behaviour of breast cancer varies widely due to genetic heterogeneity and molecular diversity⁴.
If untreated, tumour cells may invade adjacent tissues and metastasize to distant organs, most frequently the bone, lung, liver, and brain³. Advances in molecular oncology have refined classification and guided individualized therapeutic interventions⁵.
According to global cancer statistics, breast cancer accounts for more than 2 million new cases annually¹. Incidence rates are highest in North America, Western Europe, and Australia, largely due to lifestyle factors and effective screening programs². However, mortality is disproportionately high in low- and middle-income countries because of late diagnosis and limited treatment access¹⁰. The risk increases with age, particularly after 40 years². Male breast cancer constitutes approximately 1% of cases and often presents at advanced stages¹.
Female sex and increasing age are the strongest predictors². Germline mutations in BRCA1 and BRCA2 significantly increase lifetime risk and are associated with early-onset disease⁹. Additional genetic mutations such as PALB2 and TP53 also contribute to susceptibility³. Early menarche and late menopause extend oestrogen exposure and increase risk⁴.
Obesity, especially after menopause, elevates oestrogen levels and promotes carcinogenesis². Alcohol consumption demonstrates a dose-dependent association with breast cancer risk². Physical inactivity, prolonged hormone replacement therapy, and delayed childbirth are recognized contributing factors³. Lifestyle modification plays a key preventive role¹¹.
Breast cancer develops through sequential genetic and epigenetic alterations leading to dysregulated cell growth³. Amplification of the HER2 oncogene promotes aggressive tumour proliferation and poor prognosis if untreated⁴. Mutations in tumour suppressor genes such as TP53 impair genomic stability³. BRCA mutations compromise homologous recombination DNA repair mechanisms⁹. Oestrogen receptor signaling drives proliferation in hormone- dependent tumours⁴. The tumour microenvironment, including stromal cells, immune infiltrates, and angiogenic factors, facilitates invasion and metastatic spread⁶.
Emerging research highlights the importance of PI3K/AKT/mTOR signaling pathways and epigenetic modifications in tumour progression⁵.
Invasive ductal carcinoma accounts for approximately 70–80% of cases³. Invasive lobular carcinoma represents 10– 15%³. Less common variants include inflammatory breast cancer and Paget’s disease of the nipple7.
Molecular profiling divides breast cancer into distinct categories⁴:
· Luminal A: ER+, low Ki-67; favourable prognosis
· Luminal B: ER+, higher proliferation index
· HER2-enriched: HER2 overexpression; aggressive but targetable
· Triple-negative breast cancer (TNBC): ER−, PR−, HER2−; aggressive phenotype⁴ Genomic assays such as Oncotype DX assist in predicting recurrence risk and guiding therapy⁵.
Patients commonly present with a painless breast lump, nipple discharge, skin thickening, nipple inversion, or axillary lymphadenopathy⁶. Advanced disease may manifest with systemic symptoms related to metastasis³.
The clinical manifestations of breast cancer vary according to tumour size, anatomical location, molecular subtype, and stage of disease. In early stages, the condition may remain asymptomatic and is frequently detected through routine screening mammography4. When symptoms are present, the most common finding is a painless, firm breast lump with irregular borders and limited mobility3. Although pain is not typically an early symptom, some patients may experience localized tenderness or discomfort.
Alterations in breast shape, contour, or skin texture may indicate underlying malignancy. Skin dimpling or retraction occurs due to tumour involvement of Cooper’s ligaments. A characteristic “peau d’orange” appearance results from dermal lymphatic obstruction and is particularly associated with inflammatory breast cancer8. Nipple-related abnormalities, including inversion, ulceration, crusting, or spontaneous unilateral discharge—especially if bloody— should prompt immediate clinical evaluation6.
Regional spread to axillary lymph nodes may manifest as painless swelling or a palpable mass in the underarm region3. In advanced stages, systemic manifestations develop depending on metastatic involvement. Bone metastases commonly present with persistent skeletal pain or pathological fractures, while pulmonary spread may lead to dyspnoea or chronic cough. Hepatic metastasis can cause abdominal discomfort or jaundice, and central nervous system involvement may result in headaches, seizures, or focal neurological deficits6.
Symptom progression may vary across molecular subtypes. Triple-negative breast cancer often demonstrates rapid tumour growth and early progression, whereas hormone receptor–positive cancers may follow a comparatively slower clinical course3. Early recognition of warning signs and timely medical intervention significantly improve prognosis and survival outcomes10.
Population-based mammographic screening significantly reduces mortality⁴. Clinical breast examination and breast self-awareness complement screening strategies¹¹. MRI is recommended for high-risk individuals, including BRCA mutation carriers9. Artificial intelligence-assisted mammography interpretation is emerging as a supportive diagnostic tool12.
Diagnosis relies on the triple assessment approach: clinical examination, imaging, and histopathology⁵. Core needle biopsy confirms malignancy⁶. Immunohistochemistry determines ER, PR, and HER2 status, which guide therapy⁴. Molecular testing identifies actionable mutations and informs targeted treatment strategies⁵.
The TNM staging system evaluates tumour size (T), nodal involvement (N), and metastasis (M)⁵.
· Stage 0: Carcinoma in situ
· Stage I–III: Localized/regional disease
· Stage IV: Distant metastasis⁶
Accurate staging determines prognosis and therapeutic planning⁵.
Management requires multidisciplinary coordination⁵.
Breast-conserving surgery followed by radiotherapy offers survival comparable to mastectomy in early-stage disease⁵. Sentinel lymph node biopsy minimizes morbidity⁶.
Adjuvant radiotherapy reduces local recurrence and improves survival⁵.
Anthracyclines and taxanes remain foundational agents⁴. Neoadjuvant chemotherapy improves surgical outcomes and allows tumour response assessment⁶.
Tamoxifen and aromatase inhibitors reduce recurrence in ER-positive cancers⁴.
Trastuzumab and pertuzumab target HER2-positive tumours⁴. CDK4/6 inhibitors (palbociclib, ribociclib) improve survival in metastatic ER-positive disease⁵. PARP inhibitors such as olaparib benefit BRCA-mutated cancers⁹. Antibody–drug conjugates like trastuzumab-deruxtecan show promising results in advanced disease¹³.
Checkpoint inhibitors, including pembrolizumab, improve outcomes in triple-negative breast cancer⁷.
Bone is the most common metastatic site, followed by liver, lung, and brain³. Metastatic breast cancer remains incurable but treatable, focusing on survival prolongation and quality of life⁶.
Treatment-related complications include lymphedema, cardiotoxicity from HER2-directed therapy, chemotherapy- induced neuropathy, osteoporosis, infertility, and psychological distress⁴⁻⁶. Survivorship care emphasizes long-term monitoring and supportive interventions¹⁰.
Lifestyle modifications, including maintaining optimal body weight, physical activity, and limiting alcohol intake, reduce risk². Genetic counselling is recommended for high-risk families⁹. Prophylactic mastectomy and chemoprevention with selective oestrogen receptor modulators may be considered in select individuals⁹.
Precision medicine using genomic sequencing enables individualized therapy⁵. Liquid biopsy detecting circulating tumour DNA facilitates real-time disease monitoring⁶. Artificial intelligence–assisted imaging enhances diagnostic accuracy and reduces false-positive rates¹²”. Novel antibody–drug conjugates and personalized cancer vaccines are under investigation¹³.
Breast cancer remains a major global health challenge with significant clinical and socioeconomic impact¹. Advances in molecular biology, targeted therapies, and immunotherapy have improved survival outcomes⁴⁻⁷. However,metastasis, treatment resistance, and disparities in healthcare access continue to limit global control efforts¹⁰. Continued research, early detection strategies, and equitable healthcare policies are essential to reduce the global burden of breast cancer.
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Received on 17.04.2026 Revised on 12.05.2026 Accepted on 01.06.2026 Published on 10.07.2026 Available online from July 14, 2026 Res.J. Pharmacology and Pharmacodynamics.2026;18(3):297-300. DOI: 10.52711/2321-5836.2026.00040 ©A and V Publications All right reserved
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