If stomach cancer has recurred where surgical operations are not applicable, some radiotherapies are considered to be implemented as an additional treatment with chemotherapies.
However, transferring a sufficient radiation dose is hard to achieve since normal organs around the abdominal sites (including duodenum, small and large intestine, liver, kidney) are vulnerable to radiation.
In this case, proton treatment can be applied in order to increase the tumor control rate safely.

In the case of stomach cancer, the role regarding radiotherapy is still controversial, however, according to the randomized 3 phase study implemented by our hospital, a tumor was removed and the progression-free survival was increased when the combined treatment of chemotherapy and radiotherapy were applied to the stomach cancer with lymph nodes metastasis after the surgical operation. When applying the combined treatment of chemotherapy and radiotherapy to stomach cancer with lymph nodes metastasis after surgical operation, the radiation dose can be safely increased and chemotherapy can be implemented with a sufficient radiation dose without concerns regarding an acute/subacute side effects.

Moreover, according to the study conducted by our hospital to assess the transferred radiation dose by comparing proton treatment to X-ray treatments, it was confirmed that the radiation dose exposed to most of the normal organs was significantly lower in the proton treatment compared to X-ray treatments.
However, the actual clinical approach of the proton treatment is rare and there are not many cases which confirm the efficacy of the proton treatment that can remove tumors without significant side effect by transferring a high radiation does safely through applying this approach to stomach cancers where surgical operations are not applicable.