Breast Cancer Staging and Treatment

Posted on Apr 29, 2024 in Biology

ITEM 7: Study Extension (d)

Purpose and Techniques

Explorations and techniques are used to obtain information on the spread of neoplasia at the local, regional, and systemic levels. This allows for the assignment of each given stage (NFERM 1) and provides secure information for prognosis and therapeutic strategies. It also facilitates the exchange of information and evaluation of statistical data.

ITEM 8: Tumor Markers

Tumor markers are substances secreted by the tumor itself or by normal cells in response to the tumor. These markers can be detected and quantified in peripheral blood. They are generally associated with tumor burden and sometimes have prognostic value. The clinical stage depends on the following factors:

Tumor Detection

  • Low sensitivity and specificity
  • High number of false positives
  • Not useful for diagnosis of a primary tumor and its location

Uses of Tumor Markers

  • Diagnosing metastases and finding the primary tumor
  • Orienting towards the location of the tumor
  • For primary tumors already diagnosed:
  1. Obtain a baseline pretreatment marker
  2. Correlate the extent of disease with marker levels
  3. Evaluate the efficacy of treatment
  4. Demonstrate the existence of residual disease
  5. Predict relapses

ITEM 10: Pathological Classification of Breast Cancer

Noninvasive Carcinoma

  • Ductal carcinoma in situ: A premalignant situation, often bilateral and multicentric.
  • Lobular carcinoma in situ: A premalignant situation with the presence of microcalcifications.

Invasive Carcinoma

  • Invasive ductal carcinoma: 80% of breast cancers, stony hard.
  • Invasive lobular carcinoma: 5% of breast cancers, bilateral and multicentric.
  • Other histological types: tubular, medullary, mucinous, papillary, infiltrating inflammatory, mesenquinales, and secondary tumors (metastasis).

T Classification of Breast Cancer

  • Tx: Unable to assess the existence of the tumor.
  • T0: No primary tumor.
  • Tis: In situ.
  • T1: Tumor smaller than 2 cm.
  • T2: Tumor larger than 2 cm but smaller than 5 cm.
  • T3: Tumor larger than 5 cm.
  • T4: Tumor of any size that extends to:
    • T4a: Chest wall
    • T4b: Skin
    • T4c: Chest wall and skin
    • T4d: Inflammatory carcinoma

Treatment of Breast Carcinoma In Situ

  • Conservative surgery + external radiotherapy: 50 Gy (total dose) with an 8.2% recurrence rate.
  • Mastectomy (radical surgery): If conservative surgery is not possible.

Note: Axillary lymphadenectomy is rarely indicated due to the low risk of axillary involvement in carcinoma in situ. Postoperative mammography is performed to confirm complete removal.

Treatment of Stage 1 Breast Cancer

  • Radical or conservative surgery + RT (external radiotherapy): Provided with lymphadenectomy.
  • Sentinel node biopsy: Used to identify the first node in the lymphatic chain that receives lymph flow.
  • Adjuvant chemotherapy: Used in high-risk patients with axillary involvement.
  • Adjuvant hormone therapy: If the patient is hormone receptor-positive.
  • Radiotherapy: If conservative surgery is performed, the whole mammary gland is irradiated before 16 weeks after surgery with a dose of 50 Gy.

Factors Influencing Choice Between Radical or Conservative Surgery + RT

  • Tumor size greater than 3 cm
  • Small breast size
  • Microcalcifications
  • Multicentric tumors
  • Extensive intraductal component
  • Patient’s age and preference

“Boost” Technique

This technique involves administering an additional dose to the tumor bed area. It is advisable if there is microinvasion of resection margins, presence of an intraductal component, or a high-grade tumor histologically.

Treatment of Stage 2 Breast Cancer

  • Surgery: Mastectomy or conservative surgery + RTE, always associated with axillary lymphadenectomy.
  • Adjuvant radiotherapy: Always after conservative surgery, irradiating the entire breast. After mastectomy, it is only indicated in high-risk patients (4 or more involved nodes, deep narrow margin, affected vascular or lymphatic involvement, tumor size greater than 3 cm).
  • Adjuvant chemotherapy and hormone therapy: Increases overall survival and disease-free survival. Hormone therapy is only possible if the patient is hormone receptor-positive.

Treatment of Stage 3 Breast Cancer

If axillary lymph nodes are mobile, surgery is the primary treatment:

  • Radical surgery: Radical mastectomy or modified radical mastectomy.
  • Adjuvant radiotherapy: Chest wall and lymph node chains with a boost if resection margins are narrow or positive.
  • Adjuvant chemotherapy and hormone therapy: If lymph nodes are not operable or fixed due to very large tumors, neoadjuvant chemotherapy is given before surgery.

Treatment of Stage 4 Breast Cancer

Treatment depends on the presence or absence of metastasis:

  • Minimal or absent visceral disease and hormone receptor-positive: Hormone therapy with tamoxifen or ovariectomy.
  • Visceral disease or hormone receptor-negative: Chemotherapy.

Target Volume for Radiotherapy in Breast Cancer

  • Complete breast (if conservative surgery) or chest wall scar (if not conservative or radical)
  • Tumor bed (if conservative surgery) with boost
  • Axillary lymph nodes (anteroposterior)
  • Supraclavicular lymph nodes (anteroposterior)
  • Internal mammary lymph nodes (anteroposterior)

Limitations of Conventional Radiotherapy Simulation for Breast Fields

  • Upper limit: Located at the 2nd intercostal space. If the supraclavicular field is included, it becomes the lower limit.
  • Lower limit: Located between 1 and 2 cm below the inframammary fold.
  • Medial limit: Located where the root of the breast implantation begins. If the internal mammary field is included, the medial boundary is the lateral border of the internal mammary field.
  • External limit: Located where the outer root of the breast ends.