Abscopal effect induced by modulated radiation therapy and pembrolizumab in a patient with pancreatic metastatic lung squamous cell carcinoma

Abscopal Effect on Bone Metastases from Solid Tumors: A Systematic Review and Retrospective Analysis of Challenge within a Challenge

BACKGROUND

Abscopal effect (AE) describes the ability of radiotherapy (RT) to induce immune-mediated responses in nonirradiated distant metastasis. Bone represents the third most frequent site of metastasis and an immunologically favorable environment for the proliferation of cancer cells. We revised the literature, searching documented cases of AE involving bone metastases (BMs) and evaluated the incidence of AE involving BMs in patients requiring palliative RT on BMs or non-BMs treated at our department.

METHODS

Articles published in the PubMed/MEDLINE database were selected using the following search criteria: ((abscopal effect)) AND ((metastases)). Patients with BMs, who underwent performed bone scintigraphy before and at least 2-3 months after RT, were selected and screened between January 2015 and July 2022. AE was defined as an objective response according to the scan bone index for at least one nonirradiated metastasis at a distance > 10 cm from the irradiated lesion. The primary endpoint was the rate of AE on BMs.

RESULTS

Ten cases experiencing AE of BMs were identified from the literature and eight among our patients.

CONCLUSIONS

The analysis performed here suggests the use of hypofractionated radiotherapy as the only triggering factor for AE of BMs through the activation of the immune response.

Modeling of radiation effects to immune system: a review

Cancer metastasis is the major cause of cancer mortality and accounts for about 90% of cancer death. Although radiation therapy has been considered to reduce the localized cancer burden, emerging evidence that radiation can potentially turn tumors into an in situ vaccine has raised significant interest in combining radiation with immunotherapy. However, the combination approach might be limited by the radiation-induced immunosuppression. Assessment of radiation effects on the immune system at the patient level is critical to maximize the systemic antitumor response of radiation. In this review, we summarize the developed solutions in three different categories for systemic radiation therapy: blood dose, radiation-induced lymphopenia, and tumor control. Furthermore, we address how they could be combined to optimize radiotherapy regimens and maximize their synergy with immunotherapy.

Solitary pancreatic metastasis from squamous cell lung carcinoma: A case report and review of literature

BACKGROUND

Pancreatic metastases from squamous cell lung carcinoma (SCLC) are unusual. These lesions are often asymptomatic and detected incidentally or during follow-up investigations, occasionally several years after removal of the primary tumor.

CASE SUMMARY

A 56-year-old male with SCLC developed jaundice 1 mo after the cancer diagnosis. An abdominal computed tomography (CT) scan showed a mass in the pancreatic head with distention of both intra- and extrahepatic biliary ducts. Endoscopic retrograde cholangiopancreatography and sphincterotomy were performed first, culminating with plastic biliary stent placement. Cytological examination of the pancreatic mass sample collected by fine-needle aspiration (FNA) under endoscopic ultrasound (EUS) guidance revealed the presence of malignant cells compatible with well-differentiated squamous cell carcinoma. After liver function normalized, chemotherapy was initiated with carboplatin and paclitaxel; however, 4 d later, the patient presented dysphagia. Cervico-thoraco-abdominal CT showed tracheoesophageal fistula and stent migration. After replacement with a 10 cm/10 mm uncovered metallic biliary stent and treatment of the tracheoesophageal fistula with a fully covered esophageal stent, the patient was able to start oral feeding progressively. He died 9 mo after the initial diagnosis.

CONCLUSION

The diagnosis of pancreatic metastasis from SCLC is challenging for clinicians. EUS-FNA is the primary exam for confirmatory diagnosis.

Abscopal effect of radiation therapy and nivolumab in a patient with combined small-cell lung cancer: a case report

The paradigm for combined small-cell lung carcinoma (C-SCLC) is according to standard SCLC treatment with poor outcomes. The efficacy of immune checkpoint inhibitor (ICI) monotherapy for pretreated SCLC is still limited. Clinical researches exploring radiotherapy combined with immunotherapy showed promising synergistic effects in several tumors. We report one C-SCLC case after resistant to comprehensive treatment receiving nivolumab combined with radiotherapy achieving clinical complete remission (CCR). The combination module of ICI and radiation could be an option for relapsed C-SCLC, and the prognostic indicators need further research.

Abscopal Effects in Metastatic Cancer: Is a Predictive Approach Possible to Improve Individual Outcomes?

Patients with metastatic cancers often require radiotherapy (RT) as a palliative therapy for cancer pain. RT can, however, also induce systemic antitumor effects outside of the irradiated field (abscopal effects) in various cancer entities. The occurrence of the abscopal effect is associated with a specific immunological activation in response to RT-induced cell death, which is mainly seen under concomitant immune checkpoint blockade. Even if the number of reported apscopal effects has increased since the introduction of immune checkpoint inhibition, its occurrence is still considered rare and unpredictable. The cases reported so far may nevertheless allow for identifying first biomarkers and clinical patterns. We here review biomarkers that may be helpful to predict the occurrence of abscopal effects and hence to optimize therapy for patients with metastatic cancers.