PET-CT evaluation of the curative effect of crizotinib on malignant myofibroblastoma with rare mutation of ALK R401: a case report and literature review

OBJECTIVE: The purpose of this article is to explore the targeted treatment of malignant myofibroblastoma and evaluate the role of neoplasm metabolite markers in the evaluation of efficacy after targeted therapy. METHOD: This report described a case of myofibroblastic sarcoma with rare mutation of ALK R401 in a 58-year-old man prescribed with crizotinib, to evaluate its curative effect by positron emission tomography coupled with computed tomography (PET-CT). After the progressive disease in the brain, bevacizumab combined with crizotinib was administered. The Response Evaluation Criteria in Solid Tumors (RECIST), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were used to assess the efficacy. The efficacy was assessed by comparing changes in MTV and TLG. RESULT: After the treatment of crizotinib, the tumor volume was decreased. However, bevacizumab combined with crizotinib had not improved the prognosis. The change of MTV and TLG was consistent with the efficacy. The increase of MTV and TLG is an early indicator of the poor prognosis of patients. CONCLUSION: The treatment of the crizotinib patient with the mutation of ALK R401 was effective. The values of MTV and TLG reflected the prognosis earlier than RECIST.