What is the diagnosis and treatment for Invasive Ductal Carcinoma (IDC)?

From the Guidelines

Invasive ductal carcinoma should be treated with a multidisciplinary approach, including surgery, radiation therapy, and adjuvant therapy based on cancer characteristics, as recommended by the most recent guidelines 1. The treatment of invasive ductal carcinoma (IDC) typically involves surgery, either lumpectomy with radiation or mastectomy, often followed by adjuvant therapy based on cancer characteristics.

• For early-stage IDC, standard treatment includes:
  • Surgical removal of the tumor
  • Sentinel lymph node biopsy to check for spread
  • Radiation therapy if breast-conserving surgery was performed
• Systemic treatments may include:
  • Chemotherapy (such as adriamycin/cyclophosphamide followed by paclitaxel)
  • Hormone therapy (tamoxifen or aromatase inhibitors like anastrozole for 5-10 years) for hormone receptor-positive tumors
  • Targeted therapy (trastuzumab for 1 year) for HER2-positive disease
• Treatment decisions depend on:
  • Tumor size
  • Grade
  • Hormone receptor status
  • HER2 status
  • Lymph node involvement
  • Genomic testing results According to the most recent guidelines 1, the pathological diagnosis should be based on a core needle biopsy, and the final pathological diagnosis should be made according to the World Health Organization (WHO) classification and the eighth edition of the American Joint Committee on Cancer (AJCC) tumour, node, metastasis (TNM) staging system.
• The pathological report should include:
  • Presence/absence of ductal carcinoma in situ (DCIS)
  • Histological type
  • Grade
  • Immunohistochemistry (IHC) evaluation of ER status
  • IHC evaluation of PgR and HER2 expression or HER2 gene amplification Regular follow-up care is essential, including mammograms, physical exams, and sometimes blood tests, as IDC is dangerous because cancer cells can spread through the bloodstream or lymphatic system to other parts of the body, but with early detection and appropriate treatment, many patients have excellent outcomes, as supported by the guidelines 1.

From the FDA Drug Label

In women with DCIS, following breast surgery and radiation, tamoxifen citrate tablets are indicated to reduce the risk of invasive breast cancer The primary objective was to determine whether 5 years of tamoxifen therapy (20 mg/day) would reduce the incidence of invasive breast cancer in the ipsilateral (the same) or contralateral (the opposite) breast For the primary endpoint, the incidence of invasive breast cancer was reduced by 43% among women assigned to tamoxifen (44 cases-tamoxifen, 74 cases-placebo; p = 0.004; relative risk (RR) = 0.57,95% CI: 0.39 to 0. 84)

• Invasive ductal carcinoma is a type of breast cancer that begins in the milk ducts of the breast.
• The provided text does not directly address the treatment of invasive ductal carcinoma with tamoxifen.
• However, it does discuss the use of tamoxifen in reducing the risk of invasive breast cancer in women with ductal carcinoma in situ (DCIS) 2.
• The results of the NSABP B-24 trial show that tamoxifen reduces the incidence of invasive breast cancer by 43% in women with DCIS 2.
• It is essential to note that the provided information does not directly address the treatment of invasive ductal carcinoma, and therefore, no conclusion can be drawn regarding its treatment with tamoxifen.

From the Research

Invasive Ductal Carcinoma Overview

• Invasive ductal carcinoma (IDC) is the most common type of breast cancer, primarily affecting women in the United States and across the world 3.
• IDC causes include mutations on BRCA1 and BRCA2, different levels of expression of specific genes in signaling pathways, menopause status, alcohol consumption, aging, and hormone imbalances 3.
• Prompt IDC diagnosis and early intervention have been reported to demonstrate a greater probability of eradicating IDC and preventing further recurrence in the future 3.

Treatment Approaches

• Treatment options for IDC include surgery, radiation, and systemic treatment 4, 5.
• Whole-breast radiation therapy following breast-conserving surgery (BCS) was consistently associated with a reduced incidence of local DCIS recurrence and local invasive carcinoma 4.
• Tamoxifen use reduced risk of recurrent DCIS or invasive carcinoma 4.
• Treatment with lumpectomy and radiotherapy was associated with a significant reduction in breast cancer mortality compared with either lumpectomy alone or mastectomy alone 5.

Patient Experiences and Decision-Making

• Breast cancer survivors' experiences can aid future patients in making decisions between mastectomy and lumpectomy 6.
• Mastectomy patients reported less chronic pain frequency and lower incidence of post-surgical side effects compared to lumpectomy patients, but lower cosmetic satisfaction 6.
• Lumpectomy patients reported being more satisfied with cosmetic outcomes, but almost all reported radiation side-effects 6.
• Overall surgical treatment satisfaction was similar between mastectomy and lumpectomy respondents 6.

Complex Cases and Future Research

• Bilateral breast cancer with distinct histological subtypes poses a significant clinical challenge, requiring an individualised approach to management 7.
• The optimal treatment of synchronous bilateral breast cancers with differing histological subtypes remains uncertain, highlighting the need for further research 7.