What do these records reveal about a female patient with triple‑negative invasive ductal carcinoma of the left breast receiving neoadjuvant docetaxel, carboplatin, and pembrolizumab, including her up‑to‑date immunizations, endocrine laboratory findings (low thyroid‑stimulating hormone, low cortisol and adrenocorticotropic hormone), anemia, leukopenia, and her multiple comorbid conditions?

Medical Record Summary: Triple-Negative Breast Cancer Patient on Neoadjuvant Chemoimmunotherapy

Cancer Diagnosis and Treatment Status

These records document a patient with stage cT2N0 grade 3 invasive ductal carcinoma of the left breast (triple-negative subtype) currently receiving neoadjuvant carboplatin, docetaxel, and pembrolizumab (NEOPACT regimen), having completed 3 of 6 planned cycles. 1

• The patient has germline BRCA-negative disease and is receiving an anthracycline-free regimen due to cardiac contraindications (history of mitral valve replacement and atrial fibrillation) 1
• Clinical response appears favorable, with tumor size decreasing from initial presentation to approximately 1 cm on physical examination 1
• The NEOPACT regimen (carboplatin AUC 6, docetaxel 75 mg/m², pembrolizumab 200 mg every 21 days) has demonstrated pathologic complete response rates of 58% and 3-year event-free survival of 86% in triple-negative breast cancer 1
• This anthracycline-free approach is appropriate given her cardiac history, as the addition of pembrolizumab to carboplatin-docetaxel shows encouraging efficacy without anthracycline-associated cardiotoxicity 1, 2

Critical Endocrine Abnormalities Requiring Immediate Attention

The laboratory findings reveal pembrolizumab-induced endocrinopathies affecting both thyroid and adrenal function, which are potentially life-threatening immune-related adverse events.

Thyroid Dysfunction

• TSH 0.32 mIU/L (reference 0.76-1.80) with Free T4 1.60 ng/dL indicates subclinical hyperthyroidism 3
• This pattern is consistent with pembrolizumab-induced thyroiditis, which typically progresses through a hyperthyroid phase followed by hypothyroidism 3
• Serial thyroid function testing every 3-4 weeks is mandatory to detect progression to overt hypothyroidism requiring levothyroxine replacement 3

Adrenal Insufficiency

• Morning cortisol of 1.8 µg/dL (reference 5-25 µg/dL for 8-10 AM) with ACTH <5 pg/mL (reference 6-50 pg/mL) confirms secondary adrenal insufficiency from pembrolizumab-induced hypophysitis 3
• This represents a medical emergency requiring immediate glucocorticoid replacement to prevent adrenal crisis, particularly during physiologic stress (infection, surgery, trauma) 3
• Hydrocortisone 15-25 mg daily in divided doses (typically 10 mg morning, 5 mg afternoon) should be initiated immediately, with stress-dose protocols (100 mg IV hydrocortisone every 8 hours) for acute illness or surgery 3
• The provider's plan to "arrange thyroid and adrenal monitoring" is insufficient—active treatment with glucocorticoid replacement must begin now, not just monitoring 3

Hematologic Toxicity from Chemotherapy

The complete blood count reveals significant chemotherapy-induced cytopenias that require close monitoring but do not currently mandate treatment delay.

Anemia

• Hemoglobin 8.8 g/dL (reference 11.7-15.5) with hematocrit 27.8% (reference 35.0-47.0) represents grade 2 anemia 4
• The normocytic indices (MCV 93 fL, MCH 29.4 pg, MCHC 31.7 g/dL) with baseline thalassemia trait suggest combined chemotherapy-induced and chronic anemia 4
• Intravenous iron supplementation (ferumoxytol 510 mg) is already prescribed, which is appropriate for chemotherapy-induced anemia 4
• Chemotherapy should proceed as scheduled (cycle 4) without dose reduction, as maintaining dose intensity is critical for optimal outcomes in curative-intent treatment 4
• Transfusion threshold is hemoglobin <7-8 g/dL in asymptomatic patients or <10 g/dL if symptomatic (dyspnea, tachycardia, chest pain) 4

Leukopenia

• White blood cell count 6.8 K/µL (reference 4.0-11.0) is within normal range, but absolute neutrophil count calculation from the differential is needed 4
• The patient declined pegfilgrastim prophylaxis due to bone pain concerns, which increases risk of febrile neutropenia 4
• Mandatory growth factor support (filgrastim or pegfilgrastim) should be strongly reconsidered, as elderly patients with multiple comorbidities face higher myelosuppression risk 4

Comprehensive Comorbidity Burden

This patient exemplifies the complex multiple chronic conditions (MCCs) population described in ASCO guidelines, requiring integrated management of cancer treatment alongside numerous comorbidities. 3

Cardiovascular Disease

• Hypertension with blood pressure 129/83 mmHg (previous visit 134/74 mmHg) on metoprolol tartrate 25 mg twice daily 3
• Atrial fibrillation on anticoagulation with apixaban 5 mg twice daily 3
• History of mitral valve replacement (mechanical or bioprosthetic not specified) 3
• These cardiac conditions appropriately contraindicated anthracycline-based chemotherapy due to cardiotoxicity risk 1

Metabolic Disorders

• Type 2 diabetes (non-obese) managed with metformin 500 mg three times daily and semaglutide 1 mg subcutaneously weekly 3
• Fasting glucose 105 mg/dL (reference 70-100) indicates adequate glycemic control despite corticosteroid exposure from chemotherapy premedication 3
• Hyperlipidemia on atorvastatin 20 mg daily (lipid panel from primary care: total cholesterol 237 mg/dL, LDL 175 mg/dL, HDL 41 mg/dL, triglycerides 107 mg/dL) 3

Pulmonary Disease

• Asthma managed with albuterol inhaler, fluticasone nasal spray, and montelukast 10 mg nightly 3
• Oxygen saturation 98% on room air indicates stable respiratory status 3

Chronic Pain Syndromes

• Fibromyalgia and neuropathic pain managed with gabapentin 400 mg three times daily and baclofen 10 mg twice daily 3, 5
• Hydrocodone/acetaminophen 10 mg/325 mg every 6 hours as needed for breakthrough pain 5
• Mild grade 1 neuropathy reported, which is expected with docetaxel but not yet requiring dose modification 1

Psychiatric Conditions

• ADHD and PTSD (medications not specified in current medication list) 3
• Depression screening should be performed regularly, as this is among the 10 most common comorbidities in breast cancer patients and negatively impacts treatment adherence 3, 5

Gastrointestinal Issues

• Proton pump inhibitor (pantoprazole 40 mg) for gastroesophageal reflux disease 3
• Mild grade 1 diarrhea resolving with loperamide, consistent with pembrolizumab-related colitis (though severe immune-mediated colitis would require corticosteroids and pembrolizumab discontinuation) 1, 2

Immunization Status

The vaccination record demonstrates appropriate preventive care with up-to-date immunizations, though timing relative to chemotherapy cycles requires consideration.

• Multiple influenza vaccinations (Flulaval, Fluarix, Flucelvax) administered annually, most recently in 2024 3
• Pneumococcal vaccination with both Pneumovax-23 (PPSV23) and Prevnar-20 (PCV20), providing comprehensive pneumococcal coverage 3
• Tdap (Adacel) booster for tetanus-diphtheria-pertussis 3
• COVID-19 vaccination series with Pfizer monovalent vaccines (both purple cap and gray cap formulations indicating different product generations) 3
• Live vaccines are contraindicated during chemotherapy and immunotherapy, but inactivated vaccines (influenza, pneumococcal, COVID-19, Tdap) are safe and recommended 3
• Optimal timing for vaccination is either before chemotherapy initiation or >2 weeks after chemotherapy cycle when neutrophil recovery occurs, to maximize immune response 3

Surgical Planning

The patient plans bilateral mastectomy without reconstruction despite negative germline genetic testing, which represents a personal preference requiring informed consent discussion.

• Bilateral mastectomy for unilateral cancer without BRCA mutation reduces contralateral breast cancer risk by approximately 95%, but absolute risk reduction is small (0.5-1% annually) 3
• The decision for bilateral mastectomy without reconstruction should be made after discussion of body image, psychosocial impact, and lack of survival benefit compared to unilateral mastectomy with surveillance 3
• Timing of definitive surgery will occur after completion of 6 neoadjuvant cycles, with pathologic complete response assessment determining adjuvant therapy recommendations 1, 2

Prognosis and Expected Outcomes

The combination of favorable clinical response, appropriate regimen selection, and comprehensive supportive care predicts excellent disease control, though the endocrine toxicities require lifelong management.

• Patients achieving pathologic complete response with pembrolizumab-carboplatin-docetaxel have 3-year event-free survival of 98% compared to 68% without pathologic complete response 1
• The KEYNOTE-522 trial demonstrated 60-month overall survival of 86.6% with pembrolizumab-chemotherapy versus 81.7% with chemotherapy alone in early-stage triple-negative breast cancer 2
• However, pembrolizumab-induced hypophysitis causing secondary adrenal insufficiency is typically permanent, requiring lifelong glucocorticoid replacement and stress-dose protocols 3
• Thyroid dysfunction may also be permanent, potentially requiring levothyroxine replacement if progression to hypothyroidism occurs 3

Critical Action Items

1. Initiate hydrocortisone replacement immediately (15-25 mg daily in divided doses) for confirmed secondary adrenal insufficiency 3
2. Educate patient on stress-dose corticosteroid protocols (doubling or tripling dose during illness, 100 mg IV hydrocortisone for surgery/severe illness) 3
3. Repeat thyroid function tests in 3-4 weeks to monitor for progression to hypothyroidism 3
4. Reconsider pegfilgrastim prophylaxis given elderly age, multiple comorbidities, and curative-intent treatment where maintaining dose intensity is critical 4
5. Proceed with cycle 4 chemotherapy as scheduled without dose reduction, as hemoglobin 8.8 g/dL does not mandate treatment delay in asymptomatic patients 4
6. Monitor for symptoms of adrenal crisis (hypotension, hyponatremia, hyperkalemia, hypoglycemia, altered mental status) and provide emergency glucocorticoid administration instructions 3