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Objective: We aim to quantify the magnitude of setup errors in intensitymodulated radiotherapy (IMRT) treated Head and Neck cancer patients and recommend appropriate PTV margin. Methods: 60 patients with head and neck cancer required bilateral neck irradiation were planned and treated by simultaneous integrated boost IMRT technique either treated radically or postoperative. Patients undergoing image-guided radiotherapy (IGRT) each with once weekly scheduled cone beam computed tomography (CBCT). The 3D displacements, systematic and random errors were calculated. The appropriate PTV expansion was determined using Van Herk's formula. Results: Mean 3D displacement was 0.16 cm in the vertical direction, 0.14 cm in the horizontal direction and 0.16 cm in the longitudinal direction. Conclusion: Use of weekly CBCT allows the planning target volume (PTV) expansion to be reduced according to our setup. The appropriate clinical target volume (CTV)-PTV margin for our institute is 0.30 cm, 0.38 cm, and 0.33 cm in the horizontal, vertical, and longitudinal directions, respectively.

Lung cancer is the second most common cancer worldwide. Non-small cell lung cancer (NSCLC) with anaplastic lymphoma kinase ( ALK ) gene rearrangements constitutes 3-5%. Crizotinib was approved for the first-line therapy of advanced ALK-positive NSCLC patients. We present a female patient with advanced ALK-positive NSCLC who was kept on crizotinib as first-line therapy and showed progression-free survival (PFS) of 48 months despite the data suggesting that the majority of patients on crizotinib show relapse within 1 year. Further studies should focus on the molecular and biological factors and the possible effect of the long-term use of this drug.

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