Tumor Boards

Metastatic breast cancer


  • This molecular tumor board case describes a patient with metastatic breast cancer who survived for 10 years after diagnosis
  • Her disease course was notable for disease biology that evolved over time
    • Initial diagnosis in 2008: ER+/PR+/HER-2-
    • Metastatic disease demonstrated later in 2008: ER+/PR+/HER-2+
    • Repeat biopsy of metastatic disease in 2011: ER+/PR+/HER-2+
    • Repeat biopsy of metastatic focus in 2016: weakly ER+, PR-, HER-2-
  • It is not uncommon for these markers to change over time in patients receiving ongoing treatment; it is therefore valuable to obtain repeat biopsies of metastatic foci periodically
  • Evolving results may influence systemic treatment recommendations
  • Her initial treatment included a combination of cytotoxic and endocrine therapies
  • After HER-2 amplification was demonstrated, HER-2-targeted agents were utilized
  • When repeat biopsy showed non-amplification of HER-2, she resumed cytotoxic therapy alone
  • Ultimately, genomic profiling revealed the following alterations:
    • PIK3CA
    • PTEN
    • TP53
    • TLE3
    • AR/ER/HER2
    • CHEK
  • In November 2017, ASCO TAPUR expanded to offer pembrolizumab to patients with metastatic breast cancer and a high tumor mutation burden
  • This offered a non-cytotoxic option to this heavily pretreated patient with chemo- and endocrine-resistant disease
  • She ultimately received 2 cycles of treatment, achieving stable disease per RECIST criteria
  • She continued to experience significant fatigue and general debilitation
  • Four months after enrolling in the clinical trial, she elected to pursue comfort-based care alone
  • The patient enrolled in hospice care and passed away shortly thereafter, nearly 10 years after her initial diagnosis


1. http://ascopubs.org/doi/10.1200/JCO.2011.37.2482
2. http://ascopubs.org/doi/10.1200/jco.2012.30.27_suppl.92