Tag: breast-cancer-awareness

Occult Breast Cancer

Rodrigo Arrangoiz MS, MD, FACS, FSSO
  • Occult breast cancer:
    • Which manifests as axillary lymph node metastasis:
      • Without the evidence of a primary breast tumor on clinical examination or mammography
    • It accounts for 0.3% to 1.0% of all breast cancers
  • The American College of Radiology:
    • Recommends the use of MRI for occult breast cancer patients:
      • Who do not have evidence of a breast primary on traditional radiological examination (mammogram and ultrasound) and clinical examination
    • Level I evidence has shown MRI is significantly more sensitive in detecting a primary lesion than mammography or ultrasound:
      • Identifying a primary tumor in 72% of cases that were originally deemed occult
  • Patients with occult breast cancer who have abnormalities demonstrated on MRI should then undergo evaluation with:
    • Targeted ultrasound plus ultrasound-guided needle biopsy or MRI-guided needle biopsy and receive treatment according to the clinical stage of the breast cancer
  • Treatment recommendations for those with negative MRI results and occult breast cancer presenting as isolated axillary metastases:
    • Are based on nodal status and breast cancer subtype
  • Most patients with axillary metastasis from an unknown breast primary:
    • Are candidates for neoadjuvant therapy
  • A meta-analysis reported outcomes for occult breast cancer in patients undergoing axillary lymph node dissection (ALND) (with or without radiation therapy [RT]) versus mastectomy:
    • It included 7 international studies, with 241 patients presenting between 1973 and 2011
    • The mean follow up was 62 months
    • There was no difference in survival, locoregional recurrence rate, or distant metastatic rate between those occult breast cancer patients who underwent mastectomy versus those who underwent ALND + breast RT (without breast surgery)
    • Radiotherapy improves locoregional recurrence and possibly mortality rates of patients undergoing ALND
    • Based on this meta-analysis, combined ALND and RT is an acceptable approach
  • The current National Comprehensive Cancer Network guidelines:
    • Recommend that patients with negative MRI results should be treated with mastectomy plus axillary lymph node dissection (modified radical mastectomy) OR ALND plus whole-breast irradiation
  • Approximately 40% of patients undergoing neoadjuvant chemotherapy for clinically node-positive disease:
    • Are successfully down staged in the axilla, and may be able to avoid ALND
    • Although this may prove to be safe for patients with primary occult breast cancer, there are no studies that have specifically addressed the safety of sentinel lymph node biopsy with targeted axillary dissection in this highly select subset
  • Treatment gold standard for occult breast cancer presenting with axillary metastases which remain clinically positive after neoadjvuant chemotherapy, remains ALND
  • References
    1. Ge L-P, Liu X-Y, Xiao Y, et al. Clinicopathological characteristics and treatment outcomes of occult breast cancer: a SEER population-based study. Cancer Manag Res. 2018;10:4381-4391. doi: 10.2147/CMAR.S169019
    2. Ofri A, Moore K. Occult breast cancer: where are we at? Breast. 2020;54:211-215. doi: 10.1016/j.breast.2020.10.012
    3. American College of Radiology. ACR practice parameter for the performance of contrast-enhanced magnetic resonance imaging (MRI) of the breast. Accessed April 7, 2023. https://www.acr.org/-/media/ACR/Files/Practice-Parameters/MR-Contrast-Breast.pdf?la1⁄4en.
    4. de Bresser J, de Vos B, van der Ent F, Hulsewé K. Breast MRI in clinically and mammographically occult breast cancer presenting with an axillary metastasis: a systematic review. Eur J Surg Oncol. 2010;36(2):114-119. doi: 10.1016/j.ejso.2009.09.007
    5. Macedo FIB, Eid JJ, Flynn J, Jacobs MJ, Mittal VK. Optimal surgical management for occult breast carcinoma: a meta-analysis. Ann Surg Oncol. 2016;23(6):1838-1844. doi: 10.1245/s10434-016-5104-8
    6. National Comprehensive Cancer Network. Breast Cancer. Version: 3.2023. Accessed April 7, 2023. https://www.nccn.org/professionals/physician_gls/pdf/breast.pdf
    7. American Society of Breast Surgeons. Consensus Statement on Axillary Management for Patients With In-Situ and Invasive Breast Cancer: a concise overview. Accessed April 17, 2023. https://www.breastsurgeons.org/docs/statements/management-of-the-axilla.pdf