Dose comparison image credit to Oklahoma Proton Center.

Esophageal cancer is a malignancy that arises in the esophagus, the tube that carries food from the mouth to the stomach. For early-staged esophageal cancers ( small tumours without nodal spread), surgery alone is sufficient. When tumours are bigger or have spread to lymph nodes, chemotherapy and/or radiotherapy is necessary to reduce distant and local recurrence. Esophageal cancers are either adenocarcinoma ( more common in Western population) or squamous cell carcinoma ( more common in Asia). Squamous cell carcinomas are sensitive to chemo and radiotherapy, and in selected patients, surgery maybe omitted due to high response rates with chemoradiotherapy.

Here are some key points about concurrent chemoradiotherapy for esophageal squamous cell carcinoma:

1. Rationale:
   • Combining chemotherapy with radiation therapy is thought to enhance the treatment’s effectiveness by attacking cancer cells through different mechanisms.
   • The concurrent approach aims to maximize local control of the tumor and address potential micrometastases.
2. Treatment Plan:
   • Patients typically receive both chemotherapy and radiation therapy during the same time frame.
   • Chemotherapy drugs commonly used include cisplatin, 5-fluorouracil (5-FU), and taxanes. These drugs can enhance the effects of radiation on cancer cells.
3. Radiation Therapy:
   • External beam radiation therapy is the most common form used for esophageal cancer.
   • Radiation is focused on the tumor site and surrounding lymph nodes to destroy cancer cells and prevent them from dividing and growing.
4. Chemotherapy:
   • Chemotherapy drugs may be administered before, during, or after radiation therapy sessions.
   • The choice of chemotherapy drugs and their administration schedule may vary based on the specific characteristics of the tumor and individual patient factors.

However, since the esophagus is located close to the heart and lungs, traditional x-ray can increase the risk of side effects. Proton therapy is a potential treatment option for both operable and non-operable patients. Proton therapy may even be used if patients have had prior radiation for esophageal cancer.

A large study from South Korea with more than a hundred patients found a high cure rate and safety with proton beam therapy. Overall survival at 5-years were about 80, 60 and 50% for stages I, II and III respectively. This finding was confirmed in a large meta-analysis of several separate clinical studies.

Although a trial investigating higher radiotherapy dose with traditional x-ray did not show benefit, newer studies with proton therapy is underway.