Consolidative involved-node proton therapy for Stage IA-IIIB mediastinal Hodgkin lymphoma: preliminary dosimetric outcomes from a Phase II study.

To compare the dose reduction to organs at risk (OARs) with proton therapy (PT) versus three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT) in patients with mediastinal Hodgkin lymphoma (HL) enrolled on a Phase II study of involved-node radiotherapy (INRT). Between June 2009 and October 2010, 10 patients were enrolled on a University of Florida institutional review board-approved protocol for de novo "classical" Stage IA-IIIB HL with mediastinal (bulky or nonbulky) involvement after chemotherapy. INRT was planned per European Organization for Research and Treatment of Cancer guidelines. Three separate optimized plans were developed for each patient: 3D-CRT, IMRT, and PT. The primary end point was a 50% reduction in the body V4 with PT compared with 3D-CRT or IMRT. The median relative reduction with PT in the primary end point, body V4, was 51% compared with 3D-CRT (p = 0.0098) and 59% compared with IMRT (p = 0.0020), thus all patients were offered treatment with PT. PT provided the lowest mean dose to the heart, lungs, and breasts for all 10 patients compared with either 3D-CRT or IMRT. The median difference in the OAR mean dose reduction with PT compared with 3D-CRT were 10.4 Gy/CGE for heart; 5.5 Gy/CGE for lung; 0.9 Gy/CGE for breast; 8.3 Gy/CGE for esophagus; and 4.1 Gy/CGE for thyroid. The median differences for mean OAR dose reduction for PT compared with IMRT were 4.3 Gy/CGE for heart, 3.1 Gy/CGE for lung, 1.4 Gy/CGE for breast, 2.8 Gy/CGE for esophagus, and 2.7 Gy/CGE for thyroid. All 10 patients benefitted from dose reductions to OARs with PT compared with either 3D-CRT or IMRT. It is anticipated that these reductions in dose to OAR will translate into lower rates of late complications, but long-term follow-up on this Phase II INRT study is needed.

Hoppe BS ，Flampouri S ，Su Z ，Morris CG ，Latif N ，Dang NH ，Lynch J ，Li Z ，Mendenhall NP ... -  《-》

Dosimetric comparison of three different involved nodal irradiation techniques for stage II Hodgkin's lymphoma patients: conventional radiotherapy, intensity-modulated radiotherapy, and three-dimensional proton radiotherapy.

Chera BS ，Rodriguez C ，Morris CG ，Louis D ，Yeung D ，Li Z ，Mendenhall NP ... -  《-》

Radiotherapy for early mediastinal Hodgkin lymphoma according to the German Hodgkin Study Group (GHSG): the roles of intensity-modulated radiotherapy and involved-node radiotherapy.

Cure rates of early Hodgkin lymphoma (HL) are high, and avoidance of late complications and second malignancies have become increasingly important. This comparative treatment planning study analyzes to what extent target volume reduction to involved-node (IN) and intensity-modulated (IM) radiotherapy (RT), compared with involved-field (IF) and three-dimensional (3D) RT, can reduce doses to organs at risk (OAR). Based on 20 computed tomography (CT) datasets of patients with early unfavorable mediastinal HL, we created treatment plans for 3D-RT and IMRT for both the IF and IN according to the guidelines of the German Hodgkin Study Group (GHSG). As OAR, we defined heart, lung, breasts, and spinal cord. Dose-volume histograms (DVHs) were evaluated for planning target volumes (PTVs) and OAR. Average IF-PTV and IN-PTV were 1705 cm(3) and 1015 cm(3), respectively. Mean doses to the PTVs were almost identical for all plans. For IF-PTV/IN-PTV, conformity was better with IMRT and homogeneity was better with 3D-RT. Mean doses to the heart (17.94/9.19 Gy for 3D-RT and 13.76/7.42 Gy for IMRT) and spinal cord (23.93/13.78 Gy for 3D-RT and 19.16/11.55 Gy for IMRT) were reduced by IMRT, whereas mean doses to lung (10.62/8.57 Gy for 3D-RT and 12.77/9.64 Gy for IMRT) and breasts (left 4.37/3.42 Gy for 3D-RT and 6.04/4.59 Gy for IMRT, and right 2.30/1.63 Gy for 3D-RT and 5.37/3.53 Gy for IMRT) were increased. Volume exposed to high doses was smaller for IMRT, whereas volume exposed to low doses was smaller for 3D-RT. Pronounced benefits of IMRT were observed for patients with lymph nodes anterior to the heart. IN-RT achieved substantially better values than IF-RT for almost all OAR parameters, i.e., dose reduction of 20% to 50%, regardless of radiation technique. Reduction of target volume to IN most effectively improves OAR sparing, but is still considered investigational. For the time being, IMRT should be considered for large PTVs especially when the anterior mediastinum is involved.

Koeck J ，Abo-Madyan Y ，Lohr F ，Stieler F ，Kriz J ，Mueller RP ，Wenz F ，Eich HT ... -  《-》

Dosimetric comparison of involved-field three-dimensional conformal photon radiotherapy and breast-sparing proton therapy for the treatment of Hodgkin's lymphoma in female pediatric patients.

To assess the potential reduction in breast dose for young girls with Hodgkin's lymphoma (HL) treated with breast-sparing proton therapy (BS-PT) as compared with three-dimensional conformal involved-field photon radiotherapy (3D-CRT). The Clarian Health Cancer Registry was queried for female pediatric patients with the diagnosis of HL who received radiotherapy at the Indiana University Simon Cancer Center during 2006-2009. The original CT simulation images were obtained, and 3D-CRT and BS-PT plans delivering 21 Gy or cobalt gray equivalent (CGE) in 14 fractions were created for each patient. Dose-volume histogram data were collected for both 3D-CRT and BS-PT plans and compared by paired t test for correlated samples. The cancer registry provided 10 female patients with Ann Arbor Stage II HL, aged 10-18 years at the time of treatment. Both mean and maximum breast dose were significantly less with BS-PT compared with 3D-CRT: 0.95 CGE vs. 4.70 Gy (p < 0.001) and 21.07 CGE vs. 23.11 Gy (p < 0.001), respectively. The volume of breast receiving 1.0 Gy/CGE and 5.0 Gy/CGE was also significantly less with BS-PT, 194 cm(3) and 93 cm(3), respectively, compared with 790 cm(3) and 360 cm(3) with 3D-CRT (p = 0.009, 0.013). Breast-sparing proton therapy has the potential to reduce unnecessary breast dose in young girls with HL by as much as 80% relative to involved-field 3D-CRT.

Andolino DL ，Hoene T ，Xiao L ，Buchsbaum J ，Chang AL ... -  《-》

Effective dose reduction to cardiac structures using protons compared with 3DCRT and IMRT in mediastinal Hodgkin lymphoma.

We investigated the dosimetric impact of proton therapy (PT) on various cardiac subunits in patients with Hodgkin lymphoma (HL). From June 2009 through December 2010, 13 patients were enrolled on an institutional review board-approved protocol for consolidative involved-node radiotherapy (INRT) for HL. Three separate treatment plans were developed prospectively by using three-dimensional conformal radiotherapy (3DCRT), intensity-modulated radiotherapy (IMRT), and PT. Cardiac subunits were retrospectively contoured on the 11 patients with intravenous-contrast simulation scans, and the doses were calculated for all treatment plans. A Wilcoxon paired test was performed to evaluate the statistical significance (p < 0.05) of 3DCRT and IMRT compared with PT. The mean heart doses were 21 Gy, 12 Gy, and 8 Gy (relative biologic effectiveness [RBE]) with 3DCRT, IMRT, and PT, respectively. Compared with 3DCRT and IMRT, PT reduced the mean doses to the left and right atria; the left and right ventricles; the aortic, mitral, and tricuspid valves; and the left anterior descending, left circumflex, and right circumflex coronary arteries. Compared with 3DCRT and IMRT, PT reduced the radiation doses to all major cardiac subunits. Limiting the doses to these structures should translate into lower rates of cardiac toxicities.

Hoppe BS ，Flampouri S ，Su Z ，Latif N ，Dang NH ，Lynch J ，Joyce M ，Sandler E ，Li Z ，Mendenhall NP ... -  《-》