[Gastrointestinal stromal tumours bigger than 20 cm: experience with imatinib chemotherapy in neoadjuvant intention]

The size of the primary tumour is considered the most important risk factor for the development of metastasis or local recurrence in case of gastrointestinal stromal tumour (GIST). Until now no prospective data are available in the literature about the role of neadjuvant therapy with Imatinib. Between 2009 and 2012 seven patients with a giant GIST > 20 cm underwent a neadjuvant treatment with Imatinib, a radical operation, followed by an adjuvant therapy. These patients were controlled with regard to peri- and postoperative morbidity and disease-free survival. Two patients were considered not resectable and one patient showed liver metastasis at the time of diagnosis. RECIST responses to the neoadjuvant Imatinib were: 2/7 patients with stable disease, 3/7 partial response, 2/7 partial response with down-staging (resectable disease). Because of the following tumour localisations (6 gastric and 1 rectal), six gastrectomies (one en-bloc with left pancreas) and one Holm operation were performed. The patient with simultaneous liver metastasis developed a tumour progression during the follow-up but the others are still tumour free after 2 years. We detected a significant tumour volume regression due to the neadjuvant chemotherapy in cases of GIST > 20 cm (30 %). Our series showed good results for a neadjuvant therapy in cases of giant GIST with the achievement of 100 % R0 resection without a high morbidity rate (in the literature a tumor size > 10 cm and poor localisation is associated to a high risk of R1 - 2 and high morbidity). Peri- and postoperative morbidity are acceptable and the tumour free survival at 2 years is 85 %.