# Long-Term Survival of Metachronous Isolated Adrenal Metastasis in Luminal Breast Cancer: A Case Report and Literature Review

## TL;DR

A patient with luminal breast cancer survived over 20 years after developing a rare adrenal metastasis, highlighting the importance of long-term monitoring and treatment strategies.

## Contribution

This case report presents an exceptional long-term survival outcome following treatment of a rare adrenal metastasis in luminal breast cancer.

## Key findings

- The patient remained asymptomatic with no evidence of disease over 20 years after treatment.
- Adrenalectomy combined with hormonal therapy is recommended for metachronous adrenal metastasis.
- A lifelong cancer registry is proposed to track rare recurrences and improve treatment strategies.

## Abstract

Metachronous metastasis occurs many years later in cases of hormone-positive, human epidermal growth factor receptor 2 (HER2)-negative breast cancer, with the most common sites being the lymph nodes, bones, liver, lungs, and brain. The late recurrence of estrogen receptor (ER)-positive breast cancer is attributed to prolonged adjuvant therapy and the high expression of dormancy-associated genes, allowing cancer cells to survive for decades without proliferating. It is a form of chronic breast cancer that remains asymptomatic, with no clinical signs of progression or recurrence. Estrogen receptor-negative breast cancers, on the other hand, have no long-term tumor dormancy due to their fast growth and low expression of dormancy-related genes. Adrenal gland metastasis, particularly as an oligometastatic presentation, is exceedingly rare, and optimal treatment strategies remain elusive.

In this report, we present a case demonstrating long-term survival after treatment of adrenal gland metastasis, accompanied by a comprehensive literature review. At the age of 48, our patient was diagnosed with invasive ductal carcinoma of the left breast. Treatment included breast-conserving surgery, radiotherapy, and adjuvant hormone therapy. Ten years later, she developed a solitary left adrenal metastasis. Treatment included laparoscopic adrenalectomy and a change in hormonal therapy. Our patient is currently still asymptomatic with no evidence of disease. Her overall survival of over 20 years is exceptional.

Resection of the adrenal metastasis combined with systemic hormonal therapy represents the recommended approach for this metachronous metastasis. In the contemporary context, antihormonal therapy in combination with CDK4/6 inhibitors should be considered. The present case underscores the necessity of establishing a lifelong (inter)national cancer registry to document rare recurrences systematically. Such a registry would provide insights into the prevalence of uncommon scenarios and offer invaluable data on proposed treatments, facilitating the development of uniform treatment strategies.