Enhertu for Breast Cancer: 16 Real Stories

Stage IV triple-negative invasive lobular breast cancer with HER2 mutations: complete metabolic response to trastuzumab deruxtecan

Patient Info: Anonymized, Female, 70+ | Stage IV

Biomarkers: Triple-negative invasive lobular breast cancer with HER2-low/dubious staining and HER2 FISH-negative; somatic ERBB2/HER2 and mutations.

Metastatic Site: iliac bone lesions / bone metastases

As of January 2026, metastatic triple-negative invasive lobular breast cancer with HER2 mutations had a sustained complete metabolic response to trastuzumab deruxtecan for 20 months, with dose reduction for neutropenia and no pulmonary toxicity.

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Recurrent breast cancer complicated by T-DXd-associated dermatomyositis and interstitial lung disease

Patient Info: Anonymized, Female, 40s | Stage III

Biomarkers: Initial tumor had weak ER/AR, PR-negative, HER2 0. Recurrence became ER/PR/AR-negative, HER2-low, PD-L1 CPS ~30.

The cancer progressed after adjuvant therapy and again after 6 cycles of gemcitabine/carboplatin. Trastuzumab deruxtecan was followed by dermatomyositis features and interstitial pneumonia, with symptoms worsening despite glucocorticoid treatment after continued exposure.

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HER2-positive breast cancer: brain recurrence, T-DXd liver injury, and later progression

Patient Info: Anonymized, Female, 40s | Stage IV

Biomarkers: HER2-positive; hormone receptor-negative; grade 3 infiltrative breast carcinoma

Metastatic Site: brain; thoracic lymph nodes

As of October 2025, the patient had developed brain and thoracic nodal recurrence after HER2-directed treatment, experienced T-DXd-associated liver injury, progressed after later paclitaxel/trastuzumab, and died at home in December 2024 under palliative care.

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Stage IV HER2-Positive Breast Cancer: Paul's Patient Story

Patient Info: Paul Forgette, Male, 60s | Stage IV

Biomarkers: HER2-positive; triple-positive breast cancer; CHEK2 mutation

Metastatic Site: Bones; lymph nodes

By October 2025, 9 months after starting Enhertu, Paul’s Stage IV HER2-positive male breast cancer was described as dormant, not cured, with continued City of Hope care and integrative support.

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HER2-low lobular breast cancer with bone marrow involvement responding to T-DXd

Patient Info: Anonymized, Female | Stage IV

Biomarkers: Initial surgical specimen: ER-positive; PR-negative; HER2-negative. Bone marrow relapse: breast cancer infiltration with low HER2 staining.

Metastatic Site: bone marrow

Two years after starting T-DXd, this patient remained free of bone marrow disease and continued the same treatment regimen.

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HER2-low lobular breast cancer with bone marrow involvement treated with T-DXd

Patient Info: Anonymized, Female | Stage IV

Biomarkers: Initial surgical specimen: ER-positive; PR-negative; HER2-negative. Bone marrow relapse: breast cancer infiltration with low HER2 staining.

Metastatic Site: bone marrow

Two years after starting T-DXd, this patient remained free of bone marrow disease and continued the same treatment regimen.

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HER2-Positive Breast Cancer With Brain and Leptomeningeal Metastases Responding to Intrathecal Treatment

Patient Info: Anonymized, Female, 40s | Stage IV

Biomarkers: HER2-positive

Metastatic Site: brain, leptomeninges

More than 5 years after her September 2019 diagnosis, neurological symptoms had resolved, cerebrospinal fluid remained negative for tumor cells, and maintenance treatment was continuing in February 2025.

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HER2-positive breast cancer with brain metastases: responding well to T-DXd

Patient Info: Anonymized, Female, 50s | Stage IV

Biomarkers: ER-positive; PR-positive; HER2-positive / HER2 IHC 3+

Metastatic Site: brain (left cerebellum, left frontal lobe, medulla)

After 14 months and 19 doses of T-DXd, brain metastases remained controlled with no symptomatic or radiological relapse and no severe T-DXd-related adverse events.

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Stage IV HER2-Positive Breast Cancer: Stephani's Survivor Story

Patient Info: Stephani St. Cyr, Female | Stage IV

Biomarkers: HER2-targeted treatments reported; no inherited cancer gene mutation found.

Metastatic Site: Bone; liver; brain

As of March 2025, Stephani had Stage IV metastatic breast cancer involving bone, liver, and brain, had no evidence of disease since July 2021, and continued HER2-targeted/systemic therapy.

Breast Cancer Recurring Years Later With Leptomeningeal Spread and a Brief Response to Trastuzumab Deruxtecan

Patient Info: Anonymized, Female, 60s | Stage IV

Biomarkers: ER-positive, PR-positive, HER2-low

Metastatic Site: peritoneum, retroperitoneum, bones, leptomeninges

Died on May 10, 2024, about 18 years after her April 2006 breast-cancer diagnosis and about 6 years after metastatic recurrence.

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Breast Cancer Recurrence in the Small Intestine and Bone More Than 5 Years After Diagnosis

Patient Info: Anonymized, Female, 50s | Stage IV

Biomarkers: Initial ER-positive, PR-positive, HER2-negative; metastatic lesion ER-negative, PR-negative, triple negative

Metastatic Site: small intestine, bone, right fallopian tube

More than 5 years after her December 2018 diagnosis, she was alive at 1-year follow-up after metastatic recurrence, with multiple bone metastases still present.

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Stage 4 invasive ductal carcinoma: metastatic disease with bone involvement managed successfully

Patient Info: Anonymized, Female, 50s | Stage IV

Biomarkers: ER <1%; PR 0%; HER2 score 3+; Ki-67 60%

Metastatic Site: bone (12th thoracic vertebra/T12)

Stage IV HER2-positive breast cancer had improved T12 bone metastasis, major breast-tumor regression on trastuzumab deruxtecan, and pathologic complete response in the breast after mastectomy; durable systemic disease status was not reported.

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Stage IV Breast Cancer: Britney's Patient Story

Patient Info: Britney Beadle, Female, Under 40 | Stage IV

Metastatic Site: Bone; liver; brain; lungs

As of August 2023, Britney was living with Stage IV breast cancer on Enhertu every 21 days, with liver clear and bone/lung disease showing regression on the latest described scan.

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Stage IV Breast Cancer: Brittney's Patient Story

Patient Info: Brittney Beadle, Female, Under 40 | Stage IV

Metastatic Site: Bones; liver; brain; lungs

As of August 2023, Brittney was living with Stage IV breast cancer on ENHERTU every 21 days, with brain clear for 4.5 years, liver clear, and bone and lung disease regressing.

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Stage IV HR-Positive Breast Cancer: Abigail's Patient Story

Patient Info: Abigail Myers, female, Under 40 | Stage IV

Biomarkers: ER-positive, PR-positive, HER2-positive

Metastatic Site: bones, brain

Abigail continued living with Stage IV metastatic breast cancer after about 8 years of multiple treatment lines, including therapy for bone and brain metastases.

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Metastatic Breast Cancer Treatment Caused Severe Circulation Problems in Her Fingers and Toes

Patient Info: Anonymized, Female | Stage IV

Biomarkers: HER2-positive; ER-negative; PR-negative

The digital ischaemia improved after gemcitabine was stopped, without revascularisation, debridement or amputation, although a small necrotic fingertip area persisted at 3 months. Metastatic breast cancer treatment continued with further systemic lines after progression.

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