title: Early tumor cavitation with regorafenib in metastatic colorectal cancer: A case report.
abstract: Tumoral cavity formation is a characteristic phenomenon reported in anti-angiogenic therapy in lung lesions. A 57-year-old male with multiple pulmonary metastases from colorectal cancer treated with an oral tyrosine kinase inhibitor, regorafenib, exhibited a characteristic cavity formation after the first two cycles. The decrease in the size of tumors was calculated as 38%, and there were associated decreases in the serum concentrations of the tumor markers carcinoembryonic antigen and CA19-9. After eight cycles of treatment, the cavity gradually disappeared through filling-in. This unique morphological response is not only reported in lung cancer but also in liver metastasis in colorectal cancer. However, the association between morphological changes including cavity formation and clinical benefit remains controversial. Pulmonary hemorrhage and pneumothorax are well-known consequences of cavitation, as reported with the other anti-angiogenic inhibitors. Early tumor cavitation in lung metastasis may demonstrate the predictive potential of regorafenib in colorectal cancer, although it is necessary to be mindful of toxicity.
authors: Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Shinjuku-Ku, Tokyo 160-8587, Japan.
authors: Kenta
authors: K
authors: Kawasaki
authors: Keio Cancer Center, Keio University School of Medicine, Shinjuku-Ku, Tokyo 160-8587, Japan.
authors: Yasuo
authors: Y
authors: Hamamoto
authors: Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Shinjuku-Ku, Tokyo 160-8587, Japan.
authors: Masayuki
authors: M
authors: Adachi
authors: Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Shinjuku-Ku, Tokyo 160-8587, Japan.
authors: Takanori
authors: T
authors: Kanai
authors: Keio Cancer Center, Keio University School of Medicine, Shinjuku-Ku, Tokyo 160-8587, Japan.
authors: Hiromasa
authors: H
authors: Takaishi
keywords: cavity formation; colorectal cancer; lung metastasis; regorafenib