Treatment dilemmas in patients with gastrointestinal stromal tumors (GIST) who experienced imatinib-induced pneumonitis: A case series

Introduction: Imatinib has led to a phenomenal progress in the treatment of GIST. A rare and lesser -known side effect of imatinib is pneumonitis, an uncommon multicausal interstitial lung disease. Methods: Patients registered within the Dutch GIST Registry (DGR) were reviewed. For the patients identified with an imatinib-induced pneumonitis we reported the time on imatinib to develop pneumonitis, how the pneumonitis was diagnosed, graded and managed, and how the GIST treatment was managed. Cases: Of the 1934 patients registered in the DGR, 1161 patients received imatinib at some point, of which nine patients (0.8 %) were identified with an imatinib-induced pneumonitis. At time of the pneumonitis, patients received a daily imatinib dose of 200-400 mg for a mean duration of 486 days. One patient was able to continue imatinib in a lower dose, in the other eight patients imatinib was interrupted, and six of these patients started prednisolone treatment. After management of the imatinib-induced pneumonitis, four patients stopped imatinib permanently, two patients were rechallenged with imatinib, and two patients started treatment with second -line sunitinib. Conclusion: Imatinib-induced pneumonitis is a rare side effect, which may affect GIST management considerably. After the management of imatinib-induced pneumonitis, clinicians are left with difficult treatment dilemmas.