BACKGROUND: Local failure is the one of the most frequent cause of tumor related death in locally advanced non-small cell lung cancer (LAD-NSCLC). Dose escalation has the promise of increased loco-regional tumor control but is limited by the tolerances of critical organs. PATIENTS AND METHODS: To evaluate the potential of IMRT in comparison to conventional three-dimensional conformal planning (3DCRT) dose constraints were defined: Maximum dose (D(max)) to spinal cord < 48 Gy, mean lung dose </= 24 Gy, D(max) esophagus > 70 Gy in not more than 5 cm of the total length. For ten patients two plans were compared: (1) 3DCRT with 5 weekly fractions (SD) of 2 Gy to a total dose (TD) of 50 Gy to the planning target volume of second order (PTV2). If the tolerance of the critical organs was not exceeded, patients get a boost plan with a higher TD to the PTV1. (2) IMRT: concomitant boost with 5 weekly SD of 2 Gy (PTV1) and 1.5 Gy to a partial (p)PTV (pPTV=PTV2 profile of a line PTV1) to a TD of 51 Gy to the pPTV and 68 Gy to the PTV1. If possible, patients get a boost plan to the PTV1 with 5 weekly SD of 2 Gy to the highest possibly TD. RESULTS: Using 3DCRT, 3/10 patients could not be treated with TD > 50 Gy, but 9/10 patients get higher TD by IMRT. TD to the PTV1 could be escalated by 16% on average. The use of non-coplanar fields in IMRT lead to a reduction of the irradiated lung volume. There is a strong correlation between physical and biological mean lung doses. CONCLUSION: IMRT gives the possibility of further dose escalation without an increasing mean lung dose especially in patients with large tumors.
BACKGROUND: Local failure is the one of the most frequent cause of tumor related death in locally advanced non-small cell lung cancer (LAD-NSCLC). Dose escalation has the promise of increased loco-regional tumor control but is limited by the tolerances of critical organs. PATIENTS AND METHODS: To evaluate the potential of IMRT in comparison to conventional three-dimensional conformal planning (3DCRT) dose constraints were defined: Maximum dose (D(max)) to spinal cord < 48 Gy, mean lung dose </= 24 Gy, D(max) esophagus > 70 Gy in not more than 5 cm of the total length. For ten patients two plans were compared: (1) 3DCRT with 5 weekly fractions (SD) of 2 Gy to a total dose (TD) of 50 Gy to the planning target volume of second order (PTV2). If the tolerance of the critical organs was not exceeded, patients get a boost plan with a higher TD to the PTV1. (2) IMRT: concomitant boost with 5 weekly SD of 2 Gy (PTV1) and 1.5 Gy to a partial (p)PTV (pPTV=PTV2 profile of a line PTV1) to a TD of 51 Gy to the pPTV and 68 Gy to the PTV1. If possible, patients get a boost plan to the PTV1 with 5 weekly SD of 2 Gy to the highest possibly TD. RESULTS: Using 3DCRT, 3/10 patients could not be treated with TD > 50 Gy, but 9/10 patients get higher TD by IMRT. TD to the PTV1 could be escalated by 16% on average. The use of non-coplanar fields in IMRT lead to a reduction of the irradiated lung volume. There is a strong correlation between physical and biological mean lung doses. CONCLUSION: IMRT gives the possibility of further dose escalation without an increasing mean lung dose especially in patients with large tumors.
Authors: Frank Michael Klenke; Amir Abdollahi; Marc Bischof; Martha-Maria Gebhard; Volker Ewerbeck; Peter E Huber; Axel Sckell Journal: Strahlenther Onkol Date: 2010-12-23 Impact factor: 3.621
Authors: Tejan P Diwanji; Pranshu Mohindra; Melissa Vyfhuis; James W Snider; Chaitanya Kalavagunta; Sina Mossahebi; Jen Yu; Steven Feigenberg; Shahed N Badiyan Journal: Transl Lung Cancer Res Date: 2017-04