BackgroundDue to the development of diagnostic imaging technology, we have increased chance of detecting multiple primary cancers. However, simultaneous triple cancer is still a very rare finding whose frequency is not yet known. Treatment of simultaneous triple cancer is a clinical challenge because it requires multimodal strategies including surgery, chemotherapy and radiotherapy.Case presentationHere, we present the case of a 74-year-old male with triple cancer involving esophageal and pancreatic cancer, and rectal carcinoma. Each cancer was surgically resectable, but simultaneous resection of all cancers seemed to cause too much surgical stress for the patient. First, we performed a laparoscopic Hartmann’s operation for rectal cancer to minimize the risk of postoperative complications. Then treatment for pancreatic cancer was initiated by administering neoadjuvant chemotherapy with gemcitabine plus nab-paclitaxel. The pancreatic tumor shrank in size, so pancreatoduodenectomy was performed. We chose S-1 as adjuvant chemotherapy. The esophageal cancer showed regression during the treatment of the other two cancers, likely because the chemotherapeutic agents administered for pancreatic cancer had some effect on the esophageal cancer. Definitive chemoradiotherapy was selected instead of esophagectomy because the patient had already undergone two major surgeries. The patient is still alive nine months after the whole course of treatment with no sign of recurrence.ConclusionsThe treatment of triple cancer requires an elaborate strategy to determine which cancer has to be dealt with first and which can be treated later. An aggressive multimodal treatment strategy may be an important option for a patient with triple cancer.