Photodynamic Therapy of Presumed Choroidal Metastasis Secondary to Colorectal Carcinoma: Literature Review

Rare metastasis in a patient with BRAF-mutated rectal cancer: choroidal metastasis - case report and literature review

Purpose

Colorectal cancers are common and have high mortality, and metastasis is common in follow up. Choroidal metastasis is encountered rarely in rectum cancers, and there is no previous case reported from Turkey. We present our patient who developed choroidal metastasis in his cancer follow-up.

Case report

A 74-year-old male patient had undergone operation due to the diagnosis of rectum cancer two years ago, and lung (L) metastasis developed in the 4th month after the adjuvant therapy, but he refused to receive treatment and remained out of follow-up. The patient presented with complaints of decreased vision and light flashes in his eye 21 months after the diagnosis.

Management and outcome

Ocular examination revealed a choroidal mass and radiologically choroidal and multiple brain metastases were detected. In our case, whole-brain radiotherapy was administered in the treatment since there were also multiple brain metastases. However, as the ECOG (Eastern Cooperative Oncology Group) performance status of the patient was 3-4 after radiotherapy, systemic treatment was not considered appropriate, and the best supportive care was given. The patient died 2 months after the diagnosis of choroidal metastasis.

Conclusion

Currently, there are few suggestions in case reports regarding appropriate treatment approaches for the treatment of rectal cancerchoroidal metastases. Multidisciplinary approaches may be effective for local and systemic treatment. Our case highlights a pathological entity with poor prognosis, which is rarely encountered during the course of rectal adenocarcinomas, and it is the first case of choroidal metastasis reported from our country. However, we believe that it will be important to draw attention to the fact that it is the first reported case of choroid metastasis in a rectal cancer patient with a BRAF V600 E mutation, and patients with BRAF V600 E mutation may develop metastasis to atypical areas due to their aggressive biology.

Role of Metastasis Suppressor KAI1/CD82 in Different Cancers

Metastasis is one of the characteristics of malignant tumors and the main cause of death worldwide. The process of metastasis is mainly affected by tumor metastasis genes, tumor metastasis suppressor genes, tumor microenvironment, extracellular matrix degradation, and other factors. Thus, it is essential to elucidate the mechanism of metastasis and find the therapeutic targets in order to prevent the development of malignant tumors. KAI1/CD82, a member of tetraspanin superfamily of glycoproteins, has been reported as a tumor metastasis suppressor gene in various types of cancers without affecting the tumor formation. Many studies have demonstrated that low expression of KAI1/CD82 might lead to poor prognosis due to its interactions with other tetraspanins and integrins, resulting in the regulation of cell motility and invasion, cell-cell adhesion, and apoptosis. Considering its pathological and physiological significance, KAI1/CD82 could be a potential strategy for clinical predicting and preventing tumor progression and metastasis. The present review aims to discuss the role of KAI1/CD82 in metastasis for different cancers and examine its prospects as a metastasis biomarker and a therapeutic target.