the group as a whole, urinary and bowel subscales were at their lowest. (worse QOL) at ... and 3% experienced rectal incontinence > weekly, 4% and 4% experi-.
Digital Poster Discussion Abstracts S213
Volume 84 Number 3S Supplement 2012 Author Disclosure: Y. Hou: None. E. Lobos: None. K. Diao: None. L.H. Hendrix: None. A.K. Willson: None. J. Mintz: None. S.M. Miller: None. A.Z. Wang: None. X. Zhu: None. R.C. Chen: None.
1120
1119
Purpose/Objective(s): The interest in radiation therapy treatment planning which incorporates metabolic information obtained by non-invasive tumor imaging, and the consequent capability of targeting the identified biological regions with the appropriate radiation doses, has increased the interested in dose-painting techniques. These approaches, by which the dose distribution is modified to take into account the local characteristics of the tumor, generally require specific inverse-planning engines where the ‘biological’ properties associated with each individual target voxel are considered into the optimization phases. Because such devices are not yet present on the market, two methods based on a commercial treatment planning system (TPS) together with an external bio-optimization tool were applied and compared. Materials/Methods: The ‘best’ theoretical doses for each voxel of the target as a function of the corresponding signal intensity maps of the biological image-based tumor has been realized. To achieve this goal, a homemade inverse-planning tool was realized where objective functions (TCP - tumor control probability and EUD -equivalent uniform dose) can be selected to guide the target integral dose (kept constant) redistribution. The dose patterns obtained were then reprocessed in two different ways. In the first case, geometric structures have been realized by matching the shapes of some isodose levels opportunely selected. In the second case instead, the calculated doses have been inverted to create specific dose molds. Both these objects have been imported into a commercial TPS and used to replicate the pre-calculated dose maps. The critical organ dose constraints were added in the optimization process; while for the second method uniform target dose distributions were required in addition. Seven patients have been simulated to verify these two approaches, where FluoroCholine positron emission tomography imaging has been used as a surrogate marker for their prostate tumor clonogen-densities. Results: Both the proposed methods can simulate voxel-based dosepainting plans. Although neither approach was able to replicate the biologically estimated dose distributions, the first method has proved to be the most accurate in reaching ‘acceptable’ dose patterns. Because the TCPbased optimizations generally result in dose distributions which are more heterogeneous (mean coefficient of dose variation CV Z 6.8%) and with larger voxel-dose ranges than the EUD-based optimizations (CV Z 4.6%), such solutions deviating most from the theoretical. Conclusions: Being able to include, on a voxel scale, the molecularimaging data into the dose optimization process, both methods seem able to yield deliverable dose-painting treatment plans. Author Disclosure: M. Iori: None. M. Orlandi: None. E. Cagni: None. A. Botti: None. E. Mezzenga: None. V. D’Errico: None. C. Iotti: None. A. Versari: None.
Patient-reported Quality of Life Following Treatment of Prostate Cancer With Proton Therapy B.S. Hoppe,1 R.C. Nichols,1 R. Henderson,1 W.M. Mendenhall,1 C. Williams,2 J. Costa,2 C.G. Morris,1 Z. Su,1 Z. Li,1 and N.P. Mendenhall1; 1University of Florida Proton Therapy Institute, Jacksonville, FL, 2University of Florida, Jacksonville, FL Purpose/Objective(s): To evaluate patient-reported quality of life (QOL) after treatment with proton therapy for prostate cancer using the Expanded Prostate Index Composite questionnaire (EPIC). Materials/Methods: From 2006 to 2007, 366 men were treated for prostate cancer with proton therapy to doses of 78-82 Gy (RBE) at 2 Gy per fraction and enrolled on an outcomes-tracking protocol. Patients routinely responded to the 50-question EPIC at baseline and every 6-12 months after treatment. Patients were excluded from the analysis if they received androgen deprivation therapy or weekly docetaxel or died within 3 months of treatment, leaving 268 men for analysis, including 50% low-risk, 47% intermediate-risk, and 3% high-risk patients. The mean age at the start of treatment was 67 years old and 91% were white. Baseline patient-related medical characteristics included diabetes (14%), hypertension (51%), high cholesterol (54%), and blood thinners (50%). Results: EPIC data was available for 94%, 96%, 90%, and 78% at 6 months, 1, 2, and 3 years after completion of treatment. The baseline, 6 month, 1-, 2-, and 3- year QOL subscale data are shown in the Table. For the group as a whole, urinary and bowel subscales were at their lowest (worse QOL) at 1 year and subsequently improved over the following 2 years. Sexual subscales had their sharpest decline over the first year. Univariate analysis demonstrated a significantly worse sexual bother score associated with high cholesterol (p Z 0.03) and a trend in men with diabetes (p Z 0.07). Worse sexual function score was associated with blood thinner use (p Z 0.05). No other factors were significant for any other sub scale. Responses to specific questions at baseline and 2 years included: 3% and 3% requiring 1 pad for urinary incontinence daily, 2% and 3% reporting dripping of urine being a moderate or big problem, 2% and 3% experienced rectal incontinence > weekly, 4% and 4% experienced bloody stools > half the time, 1% and 2% reported that losing control of stool was a moderate or big problem. At baseline, 64% reported erections firm enough for intercourse, 67% had sexual intercourse monthly, and 41% had sexual intercourse weekly. At 2 years, 46% reported erections firm enough for intercourse, 52% had sexual intercourse monthly, and 29% had sexual intercourse weekly. Conclusions: In the first 3 years after treatment with proton therapy, QOL data as reported by EPIC demonstrated promising results with the largest decline at 1 year after treatment. Longer follow-up is needed to confirm these findings. Author Disclosure: B.S. Hoppe: None. R.C. Nichols: None. R. Henderson: None. W.M. Mendenhall: None. C. Williams: None. J. Costa: None. C.G. Morris: None. Z. Su: None. Z. Li: None. N.P. Mendenhall: None.
Digital Poster Abstract 1119; Table Mean EPIC QOL scores in men treated with proton therapy. Standard deviations in parentheses. EPIC Subscale Sexual bother Sexual function Bowel bother Bowel function Urinary bother Urinary function Urinary incontinence Urinary obstructive
Baseline 67 53 92 94 84 95 93 87
(32) (26) (8) (10) (13) (9) (14) (10)
6 months 63 48 91 91 84 93 92 86
(32) (27) (12) (13) (16) (12) (14) (14)
1 year
2 year
3 year
53 41 87 86 81 92 90 84
52 41 91 88 83 93 91 87
50 38 90 88 84 93 90 87
(32) (26) (12) (17) (17) (12) (16) (16)
(34) (27) (9) (14) (15) (10) (15) (12)
(33) (27) (9) (14) (15) (11) (15) (12)
Voxel-based Dose-painting With a Commercial Treatment Planning System by Using 2 Different Planning Methods M. Iori, M. Orlandi, E. Cagni, A. Botti, E. Mezzenga, V. D’Errico, C. Iotti, and A. Versari; ASMN-IRCCS of Reggio Emilia, Reggio Emilia, Italy
1121 Using Mid-ventilation Phase for Calculation of Treatment Plan for Lung Cancer Patients Might Not Be Optimal C. Brink,1,2 M. Nielsen,2 O. Hansen,1,3 and T.B. Nielsen1,2; 1Institute of Clinical Research, University of Southern Denmark, DK-5000 Odense, Denmark, 2Laboratory of Radiation Physics, Odense University Hospital, DK-5000 Odense, Denmark, 3Department of Oncology, Odense University Hospital, DK-5000 Odense, Denmark Purpose/Objective(s): Treatment planning and irradiation of lung cancer patients is often based on the mid-ventilation phase in order to minimize planning margins. Imaging artifacts are most pronounced in the midventilation phase due to the rapid tumor motion in this phase. Thus, tumor delineation and dose calculation on a different phase might be optimal if the treatment is still performed at the mid-ventilation phase. The only hindrance is the potential difference in dose between different respiration phases as investigated in this study.
