Dear Editors,
Recent global cancer data indicates that breast cancer is the second most common cancer and the fourth leading cause of cancer-related deaths worldwide.1 Despite advancements in various treatment modalities, including surgery, radiation therapy, chemotherapy, endocrine therapy, targeted therapy, and immunotherapy, the prognosis remains poor for patients with advanced breast cancer and distant organ metastases.2
Metastatic spread of breast carcinoma to the lower gastrointestinal tract is uncommon. In a study conducted by Da Cunha et al.,3 a case of breast cancer metastasizing to the colorectal region was documented, alongside a comprehensive analysis of existing literature on this subject. The research primarily examines metastatic occurrences in the lower gastrointestinal tract, highlighting the discordance observed between metastatic frequencies reported in postmortem examinations versus clinical investigations, and unveiling the varying metastatic propensities across distinct subtypes of breast cancer. The study underscores the importance of prompt diagnosis and intervention for suspected cases, serving as a valuable directive for clinical management.
The article outlines the correlation between E-cadherin deficiency and metastasis, a viewpoint widely accepted by the scholarly community. It suggests that E-cadherin loss facilitates epithelial-mesenchymal transition, subsequently enhancing breast cancer metastasis.4 However, one study posited that while E-cadherin depletion may heighten local invasion, it concurrently diminishes the establishment of cancer cell seeding and distant organ metastasis.5 This discrepancy necessitates further investigation.
The absence of E-cadherin has been linked to a cascade of alterations. Initially, a distinctive growth pattern emerges, whereby infiltrating tumor cells tend to organize concentrically (in a targetoid manner) around intact ducts or anatomical structures.6 This configuration minimally disrupts normal tissue architecture and has negligible impact on physiological functions, thus remaining asymptomatic. Consequently, the inconspicuous nature of these changes poses challenges in early detection, often resulting in delayed diagnosis spanning several years. As a result, numerous metastases can be observed without apparent clinical manifestations, leading to a higher rate of positive findings in postmortem examinations compared to clinical investigations.7
The inconspicuous nature of various imaging modalities and the characteristic invasive growth pattern of the tumor, primarily confined to the submucosa, pose challenges in early detection. This unique growth behavior can mask the tumor’s presence during endoscopic examinations, as the mucosa may exhibit a normal appearance in the initial stages. A vigilant approach involving deep or repeated biopsies is imperative in cases where metastatic spread is suspected due to the deceptive nature of the growth pattern. Furthermore, metastatic lesions often exhibit signet ring cell features, complicating accurate histopathological interpretation. Similarly, positron emission tomography-computed tomography (PET/CT) scans may not reliably distinguish metastatic lesions from normal tissue due to comparable physiological activity. Consequently, the identification of occult distant metastases originating from invasive lobular carcinoma through PET/CT imaging remains challenging, underscoring the complexity of diagnosing pathological alterations based on imaging findings.8
The decision-making process regarding treatment options for these individuals remains challenging. The patient’s demise, as detailed in the authors’ case study, was attributed to complications arising from liver metastasis rather than metastasis in the digestive tract. This observation is consistent with existing literature, indicating that gastrointestinal metastases are predominantly observed in cases of extensive metastatic disease, leading to an unfavorable prognosis.9 As such, a preference for non-surgical interventions is recommended for these patients due to their potential positive impact. While palliative surgery may be necessary in instances of acute complications such as bleeding, perforation, or obstruction, the primary focus of treatment should address factors posing a threat to the patient’s life.10
In summary, this study provides a crucial notification for professionals in clinical and scientific sectors, emphasizing the infrequent occurrence of gastrointestinal metastases originating from breast cancer (Fig. 1). Examination of the study’s results reveals substantial implications regarding the metastatic spread of breast cancer to the gastrointestinal tract. These findings may stimulate further investigation into the clinical characteristics, pathophysiological mechanisms, and molecular foundations of gastrointestinal metastases arising from breast cancer.
Declarations
Funding
None.
Conflict of interest
PYZ has served as an Early Career Editor of Oncology Advances since 2024. The other authors have no other potential conflicts of interest to declare.
Authors’ contributions
Manuscript drafting and writing (YZM, ZTZ, BL), figure conception and drawing (YZM), conception and design of the work (XHD, PYZ). All authors have approved the final version of the manuscript.