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Page 2 of 18 D'Angelo et al. J Cancer Metastasis Treat 2019;5:30 I http://dx.doi.org/10.20517/2394-4722.2018.86

INTRODUCTION
Breast cancer is the most common malignant tumor in the female population. Different histologies
[1]
metastatize to different organs : ductal cancer metastatizes mainly to lungs, bones and liver, while lobular
[2,3]
cancer has a tendency to metastatize to the gastrointestinal system . Gastric metastases from breast
[3,4]
cancer are not common, but the autoptic incidence is not negligible, and varies from 5% to 18% . Gastric
metastases are metachronous in most cases and even in patients with a known history of breast cancer it
may be difficult to correlate the two diseases to a common cause, since the gastric disease often presents only
[5,6]
several years after the treatment for the breast tumor . This late manifestation of the disease may lead to
erroneous diagnosis in clinical practice and a correct identification of the disease becomes possible only after
performing surgery, even though this approach is used only in limited cases. With this study we want to
compare current clinical practice found in case reports with the results presented in recent reviews.

METHODS
We performed a literature search aimed at finding reviews published from January 1st 2000 to October 31st
2018 about gastric metastasis from breast cancer and case reports on the same argument from January 1st
2013 to October 31st 2018. The results presented in the reviews and in the case reports were compared with
the aim of analyzing eventual similarity and differences in the findings discussed therein.

Characteristics of the included studies are summarized in Table 1 [7-17] , whereas characteristic of patients from
case reports (2013-2018) are reported in Tables 2-4 [9,14,18-51] .

RESULTS
Part 1. Reviews
The search for reviews about gastric metastasis from breast cancer was carried out using the combination
of words (gastric OR stomach) and (metastasis OR metastases) and (breast) for the PubMed database, using
the filter for reviews. Articles written in languages other than English, articles about primary gastric cancer
with breast metastasis and about primary breast cancer metastatizing in organs other than the stomach were
excluded. The time span considered went from January 1st 2000 to October 31st 2018 and 11 articles fulfilling
the criteria were found as a result of the search. The main aspects of the included studies are summarized in
Table 1.

Incidence
Nine of the articles reported the incidence of gastric metastasis from breast cancer: the incidence ranged
from 0.3% to 35%, with the value 2%-18% reported in 3 articles.

Breast histology
Nine reviews reached the same conclusion that the most common histological type of breast cancer
responsible for gastric metastasis is the lobular cancer. Two of the articles also reported the occurrence of
metastasis associated with different types of cancer, with lobular cancer being identified as the cause of
metastasis in 83% of the cases.

Disease Free survival
Nine of the reviews cited interval time from the appearance of the primary breast cancer to the presentation
of gastric metastasis, however the time intervals were not specifically defined, as for example two articles
reported “many years” and one article “few months to several years”. Other articles reported a median
disease free survival of 5 years, but gastric metastasis may occur up to 30 years after the primary tumor.