Metastasis to the rectum: A systematic review of the literature

Gastric cancer causing Schnitzler's metastasis: case report and systematic review of the features

BACKGROUND

Rectal metastasis from gastric cancer (GC), also known as Schnitzler's metastasis, is a rare phenomenon. The clinicopathological characteristics, outcomes, and prognostic factors of this condition remain poorly understood.

METHODS

We describe a case of GC causing Schnitzler's metastasis and present a systematic review on case reports and case series. Data extracted and analyzed include clinicopathological features, treatment modalities received, outcomes, and follow-up.

RESULTS

A total of 34 records, including our own, encompassing 41 cases were incorporated into the study. The median age of patients at admission was 59 years, with females accounting for 53.7% of cases. The predominant histological subtype of Schnitzler's metastasis was moderate-to-poorly differentiated adenocarcinoma, representing 31 cases (86.1%). Among the patients in this cohort, 38.9% exhibited signet-ring cell carcinoma. Regarding the initial diagnosis of GC, 28.6% were categorized as stage IIIA, and 28.6% were classified as stage IV. The median overall survival (OS) time was 72 months (95% confidence interval [CI]: 27-NA), while the median OS since the diagnosis of metastatic cancer was 16 months (95% CI: 9-NA).

INTERPRETATION

Schnitzler's metastasis presents a challenge in the pathology of colorectal endoscopy and may lead to treatment delays. Imaging features such as increased thickness of the intestinal wall and significant layered enhancement can aid in diagnosis; however, deep core biopsy of intestinal lesions remains the gold standard for diagnosing rectal metastases. Accurately distinguishing rectal metastases from primary rectal cancer is crucial for preventing unnecessary therapeutic interventions.

Rectal metastasis arising from breast cancer: a case report

Breast cancer is the most common cancer among women worldwide. Breast cancer often metastasizes to the regional lymph nodes, bone, brain, liver, and lungs, whereas gastrointestinal tract metastases are rare. Herein, we present a rare case of rectal metastasis from breast cancer that occurred during palliative chemotherapy. A 69-year-old female with a history of invasive ductal carcinoma, negative for hormonal receptors and positive for human epidermal growth factor receptor 2 (HER2) receptor, underwent various treatments, including neoadjuvant chemotherapy, breast-conserving surgery, and adjuvant therapy. Eight months postoperatively, the patient experienced axillary lymph node recurrence, requiring palliative chemotherapy. Despite ongoing treatment, metastatic lesions were confirmed in the lungs and pleura. During palliative chemotherapy, the patient developed anal pain, and subsequent examination revealed an infiltrating rectal lesion. Despite histological confirmation of metastatic breast carcinoma and tubular adenoma, a multidisciplinary decision was made regarding palliative chemotherapy over surgical intervention. Eribulin was administered, but due to the patient's inability to tolerate the treatment, she passed away 3 months after rectal lesion diagnosis. Although breast cancer metastasis to the rectum is rare, clinicians should consider the possibility of rectal involvement and perform a digital rectal examination if anal symptoms are present.

Development and Validation of a Novel Hypoxia Score for Predicting Prognosis and Immune Microenvironment in Rectal Cancer

Hypoxia plays a major role in various tumor types. However, few studies have concentrated on the prognostic model of hypoxia-related genes in rectal cancer and the effect of hypoxia on neutrophil-mediated immunosuppression. We performed Kaplan–Meier analysis, random survival forest analysis, and Cox regression analysis on 342 hypoxia-related genes, constructed hypoxia score in the Gene Expression Omnibus (GEO) cohort, and verified them in the Cancer Genome Atlas (TCGA) cohort. Then the patients were divided into two groups according to the risk level. The overall survival rate of the high-risk (HRisk) group was significantly higher than that of the low-risk (LRisk) group (GEO, p < 0.001; TCGA, p = 0.016). Through receiver operating characteristic and decision curve analysis, the nomogram based on hypoxia score has excellent prediction ability. Functional enrichment analysis showed that hypoxia, metastasis, inflammation, immunity, and other related pathways were enriched. The HRisk group was associated with lower tumor purity, higher immune and stromal score, higher neutrophils, and lower activated memory CD4 + T cells. More importantly, the checkpoint of neutrophil-mediated immunosuppression increased in the HRisk group. In conclusion, a hypoxia score based on 5 hypoxia-related genes can be used to predict the prognosis of rectal cancer and ANLN with a cancer-suppressing effect and SRPX (Sushi Repeat Containing Protein X-Linked) with a cancer-promoting effect may be potential therapeutic targets for rectal cancer.