Receiving Pembrolizumab? Your Breast Cancer Diagnosis May Have Been Delayed

Pembrolizumab (Keytruda), an innovative immune checkpoint inhibitor that targets the PD-1 protein, has emerged as a groundbreaking treatment option primarily for triple-negative breast cancer (TNBC), one of the most aggressive breast cancer subtypes. When your oncologist prescribes this immunotherapy, particularly for later-stage disease, it often signals a treatment for a challenging breast cancer variant—occurring in the context where five-year survival rates may have already decreased substantially from nearly 100% in early stages to approximately 66-87% for stage III and only 29-32% for stage IV. 

If you or a loved one has been prescribed Pembrolizumab, it’s worth investigating whether earlier detection of your breast cancer might have been possible. In some cases, the need for this advanced immunotherapy may indicate a missed or delayed diagnosis that could potentially have been prevented with appropriate medical vigilance.

At the Porter Law Group, we understand the critical impact of a delayed breast cancer diagnosis, particularly for aggressive subtypes like triple-negative breast cancer. Our specialized medical malpractice attorneys offer no-cost consultations to evaluate your situation and determine whether healthcare providers failed to identify your breast cancer at an earlier, more treatable stage. We are dedicated to pursuing accountability when medical negligence fundamentally alters treatment trajectories and survival prospects.

Understanding Pembrolizumab and Delayed Diagnosis

Pembrolizumab, which received FDA approval in 2020 for metastatic triple-negative breast cancer and in 2021 for high-risk early-stage TNBC, works through a revolutionary mechanism unlike traditional chemotherapy. This immunotherapy blocks the PD-1 protein, effectively releasing the “brakes” on immune cells so they can better recognize and attack cancer cells. While this approach has transformed treatment outcomes, particularly for triple-negative breast cancer patients with high PD-L1 expression (CPS ≥10), its introduction typically signals the presence of an aggressive cancer subtype or advanced disease stage.

The prescription of Pembrolizumab indicates either that your breast cancer is triple-negative (lacking estrogen receptors, progesterone receptors, and HER2 overexpression) with specific high-risk features, or that it has already advanced to a metastatic stage. While Pembrolizumab has improved outcomes for these challenging scenarios, the need for this medication often suggests that the cancer represents a particularly aggressive variant or has progressed beyond the earliest, most readily treatable stages. This progression is especially distressing when considering that breast cancer detected at stages 0-I, regardless of subtype, has an exceptional five-year survival rate exceeding 99%. At these early stages, treatment approaches are typically less intensive and more likely to result in cure.

The legal team at the Porter Law Group has represented numerous individuals with aggressive breast cancers who ultimately required advanced treatments like Pembrolizumab after healthcare professionals overlooked critical opportunities for early detection. Through comprehensive examination of medical documentation, our attorneys can identify concerning patterns where symptoms were minimized, imaging results were misinterpreted, or standard screening protocols weren’t properly followed. The significant difference between treatment options for early-stage disease versus the necessity for advanced immunotherapies like Pembrolizumab frequently suggests a potential failure in meeting the established standard of care.

Indicators of a Delayed Breast Cancer Diagnosis

Medical negligence in breast cancer diagnosis can manifest in various ways, regardless of the cancer’s molecular subtype. If you encountered any of the following situations before eventually receiving a diagnosis requiring Pembrolizumab treatment, you might have grounds for a medical malpractice claim:

• Healthcare providers downplayed or dismissed early breast symptoms (such as lumps, skin changes, or nipple abnormalities)
• Abnormal findings on mammograms, ultrasounds, or other imaging studies weren’t properly investigated
• Appropriate screening based on your specific risk factors and age wasn’t recommended
• Referrals to breast specialists were unnecessarily delayed despite concerning findings
• Necessary diagnostic testing wasn’t ordered despite persistent symptoms
• Biopsy results were incorrectly interpreted or misreported
• Molecular testing (for hormone receptors and HER2) wasn’t performed properly, potentially missing triple-negative status
• Genetic testing wasn’t considered despite significant family history of breast cancer

The Porter Law Group attorneys specialize in identifying these patterns of potential negligence through detailed reviews of medical records and collaboration with expert witnesses in oncology and diagnostic medicine. We understand that building these cases demands both legal expertise and in-depth medical knowledge regarding breast cancer progression and established standards of care. Contact us for a free case evaluation, and view the results we’ve achieved for previous clients to learn more about how we can help you recover compensation. 

How Pembrolizumab Is Used in Breast Cancer Treatment

When breast cancer is diagnosed, particularly triple-negative breast cancer with specific high-risk features, Pembrolizumab may become an important component of treatment due to its demonstrated effectiveness in enhancing immune system recognition of cancer cells. The medication functions by blocking the interaction between PD-1 (on immune cells) and PD-L1 (often expressed on cancer cells), allowing the immune system to more effectively target and destroy the cancer.

Pembrolizumab is prescribed in several clinical contexts:

• Metastatic/Advanced Triple-Negative Breast Cancer: In combination with chemotherapy for patients whose tumors express high levels of PD-L1 (combined positive score [CPS] ≥10), which represents approximately 20% of TNBC cases
• High-Risk Early-Stage Triple-Negative Breast Cancer: Used with chemotherapy before surgery (neoadjuvant) and as a single agent after surgery (adjuvant) for patients with tumors at least 1 cm with lymph node involvement, or tumors at least 2 cm without lymph node involvement
• Investigational use in other breast cancer subtypes, including some high-risk, early-stage, estrogen receptor-positive/HER2-negative breast cancers, though not yet standard of care

The medication is administered intravenously, typically 200 mg every 3 weeks or 400 mg every 6 weeks, over 30 minutes. Treatment duration varies by clinical context but may continue for up to a year in early-stage settings or longer for metastatic disease, depending on response and tolerability.

A significant consideration with Pembrolizumab is its unique side effect profile, particularly immune-related adverse events, which necessitates careful monitoring throughout treatment. Regular assessments for potential immune-mediated inflammation of various organs and systems are essential to ensure patient safety while maximizing therapeutic benefit.

While Pembrolizumab represents a major advancement in breast cancer treatment, particularly for triple-negative disease, its use—especially in metastatic settings—often indicates that the cancer has progressed beyond the earliest, most treatable stages or represents a particularly aggressive variant. In many instances, this progression or the development of aggressive biology might have been detected earlier with timely and appropriate screening and diagnostic measures.

Serious Risks and Side Effects

Pembrolizumab’s therapeutic benefits come with significant potential toxicities that require vigilant monitoring and management. These side effects are particularly concerning when considering they might have been avoided with earlier diagnosis and treatment at an earlier disease stage. Major side effects include:

1. Immune-Related Adverse Events: Pembrolizumab can cause the immune system to attack healthy organs and tissues, leading to potentially serious or life-threatening conditions affecting:
   • Lungs (pneumonitis): Causing cough, chest pain, and shortness of breath
   • Liver (hepatitis): Leading to jaundice, abdominal pain, and abnormal liver function tests
   • Colon (colitis): Resulting in severe diarrhea, abdominal pain, and bloody stools
   • Kidneys (nephritis): Causing changes in urine output and kidney function
   • Endocrine glands: Affecting thyroid, adrenal, and pituitary function, potentially causing fatigue, weight changes, and hormonal imbalances
   • Other organs and tissues: Including the heart, pancreas, skin, eyes, and nervous system
2. Infusion Reactions: Patients may experience dizziness, headache, chest tightness, trouble breathing, swelling, or allergic reactions during or after infusion, requiring careful monitoring during administration.
3. Blood Disorders: The medication can cause low blood cell counts, anemia, and increased risk of infection or bleeding, necessitating regular blood tests throughout treatment.

Common side effects experienced by many patients include:

• Fatigue and weakness
• Nausea, vomiting, diarrhea, and constipation
• Loss of appetite and weight loss
• Rash, itching, and skin changes
• Muscle, bone, or joint pain
• Cough and shortness of breath
• Mouth sores and taste changes

At the Porter Law Group, we believe these serious side effects represent an especially unjust burden when they result from preventable diagnostic delays. When healthcare providers miss opportunities for early detection of breast cancer, particularly aggressive subtypes like triple-negative disease, patients face not only reduced survival probabilities but must also endure potentially more intensive treatment regimens and associated toxicities that might have been minimized with proper medical attention.

Legal Options Following a Delayed Diagnosis

When a breast cancer diagnosis is delayed, potentially necessitating advanced treatments like Pembrolizumab at later disease stages, patients may have legitimate grounds for a medical malpractice claim. Successfully pursuing these cases requires establishing four fundamental elements:

1. Duty of Care: The healthcare provider had a professional obligation to deliver care according to accepted medical standards for breast cancer screening, diagnosis, and follow-up.
2. Breach of Standard: The provider failed to fulfill this standard through either action or inaction (such as misinterpreting imaging results, dismissing reported symptoms, failing to order appropriate tests, or not performing proper molecular testing).
3. Causation: This failure directly resulted in a delayed diagnosis, allowing the cancer to advance to a more serious stage requiring more aggressive treatment approaches.
4. Damages: The patient suffered measurable harm as a consequence, including decreased survival probability, requirement for more intensive treatment protocols, additional medical expenses, lost wages, pain and suffering, and diminished quality of life.

The Porter Law Group attorneys construct these cases through exhaustive investigation, including:

• Thorough examination of all relevant medical records
• Consultation with expert oncologists who can establish how earlier diagnosis would have altered treatment approaches and prognosis
• Detailed analysis of imaging studies, pathology reports, and molecular testing results
• Comprehensive evaluation of the medical timeline to identify critical missed opportunities
• Assessment of specific breaches in the standard of care at each stage

Our firm has successfully advocated for numerous clients in delayed breast cancer diagnosis cases throughout New York State. We understand the complex medical evidence required to demonstrate how earlier intervention would have significantly altered both treatment courses and likely outcomes. While specific results cannot be guaranteed, our established record demonstrates our commitment to securing justice for victims of medical negligence.

Legal History of Pembrolizumab

Pembrolizumab has a relatively recent but well-documented medical and legal history that can strengthen potential malpractice claims related to delayed breast cancer diagnosis. Its FDA approval in 2020 for metastatic triple-negative breast cancer with high PD-L1 expression was based on the landmark KEYNOTE-355 trial, which demonstrated improved overall survival from 16.1 months with chemotherapy alone to 23.0 months with the addition of pembrolizumab.

The subsequent 2021 approval for high-risk early-stage triple-negative breast cancer as neoadjuvant and adjuvant therapy, supported by the KEYNOTE-522 trial, established pembrolizumab as the first immunotherapy approved for early-stage breast cancer. This marked a significant advancement in treatment options for patients with this aggressive breast cancer subtype.

The medical community has established evolving guidelines regarding breast cancer screening, diagnosis, molecular subtyping, and treatment protocols. When a patient ultimately requires advanced immunotherapies like Pembrolizumab following missed opportunities for earlier diagnosis, these established guidelines can serve as compelling evidence of deviations from the standard of care.

Additionally, the documented survival benefits in both metastatic and high-risk early-stage settings underscores the critical importance of timely diagnosis and treatment initiation, particularly for aggressive subtypes like triple-negative breast cancer. Delays in diagnosis that result in more advanced disease at presentation represent significant lost opportunities for optimal treatment outcomes.

Why Choose the Porter Law Group

The lawyers at the Porter Law Group have decades of experience representing individuals and families whose lives have been devastated by catastrophic injuries. We have obtained large settlements and verdicts in courts throughout the State of New York. We are a state-wide firm that handles cases with a hometown feel.

Our clients come to us looking for guidance and answers. With seasoned trial lawyers, the Porter Law Group has the resources necessary to help you navigate the most complex cases, against goliath insurance companies that will stop at nothing to prevent you from receiving the compensation you deserve.

You only get one chance to hire the best lawyer for you and your family. Hire the breast cancer lawyers most recommended by former clients and local attorneys, and the firm that obtains superior results.

When you or a loved one’s life has been devastated by a serious personal injury in New York, don’t hire a lawyer without calling the Porter Law Group to learn why so many of our clients are thankful they trusted us with their case in their time of need.

When to Contact a Cancer Misdiagnosis Attorney

If you or a loved one has received a diagnosis of breast cancer requiring treatment with Pembrolizumab, consider consulting with our medical malpractice attorneys if:

• You previously reported breast symptoms that healthcare providers dismissed or minimized
• Abnormal findings appeared on mammograms or other imaging studies that weren’t appropriately addressed
• You needed to persistently advocate before receiving proper diagnostic evaluation
• Unusual delays occurred between your initial concerns and receiving a definitive diagnosis
• Medical professionals assured you not to worry about symptoms that later proved to be cancer
• Your healthcare provider failed to recommend appropriate screening protocols based on your age and risk profile
• Upon switching providers, a new doctor immediately identified concerning findings that previous providers overlooked
• Your pathology results or molecular testing were incorrectly interpreted, resulting in delayed treatment

The earlier you contact our firm, the better positioned we’ll be to preserve critical evidence and begin constructing your case.

Consult with a Breast Cancer Misdiagnosis Lawyer Today

If you or someone you love is now facing breast cancer requiring Pembrolizumab treatment following what you believe might have been a preventable diagnostic delay, the Porter Law Group stands ready to assist. Our experienced medical malpractice attorneys understand the profound impact of delayed cancer diagnosis and are committed to helping you secure the compensation you deserve.

We handle all medical malpractice cases on a contingency fee basis, meaning you pay absolutely nothing unless we recover compensation on your behalf. This arrangement allows you to concentrate on your health and treatment while we vigorously pursue justice for you.

The window for action is limited by New York’s statute of limitations for medical malpractice claims. Don’t postpone seeking the legal guidance you need. Contact the Porter Law Group today at 833-PORTER9 or info@porterlawteam.com to schedule your free, confidential consultation.

Together, we can hold negligent healthcare providers accountable and secure the resources necessary for your ongoing treatment, lost income, and the pain and suffering caused by unnecessary progression of your breast cancer.

DISCLAIMER: This article is not intended to provide medical advice. The medical information provided is for general informational purposes only. Always consult with qualified healthcare professionals regarding any medical conditions or treatments. This content does not establish an attorney-client relationship, and prior results do not guarantee a similar outcome. Every case is unique and outcomes depend on the specific facts and circumstances involved.