This clinical trial is focused on studying a type of cancer known as esophageal carcinoma, which affects the esophagus, the tube that carries food from the mouth to the stomach. The study is investigating the effects of a medication called pembrolizumab, also known by its code name MK-3475, compared to a placebo. Pembrolizumab is a type of treatment that helps the immune system fight cancer cells. The purpose of the study is to see how well pembrolizumab works when given alongside standard cancer treatments, which include chemotherapy and radiation therapy, in people with esophageal carcinoma.

Participants in the study will receive either pembrolizumab or a placebo, in addition to their regular cancer treatment. The study will last for a period of time during which participants will receive treatment and be monitored for any changes in their health. The study aims to understand how pembrolizumab affects the length of time participants live without the cancer getting worse and overall survival. The study will also look at any side effects that participants may experience during the treatment.

Other medications involved in the study include calcium folinate, folinic acid, fluorouracil, cisplatin, and oxaliplatin, which are commonly used in cancer treatment. These medications are given as solutions for infusion, meaning they are administered directly into the bloodstream through a vein. The study is designed to provide valuable information about the effectiveness and safety of pembrolizumab in treating esophageal carcinoma, potentially leading to improved treatment options for patients with this type of cancer.