3D heterogeneous dose distributions for total body irradiation patients.

One major objective of total body irradiation (TBI) treatments is to deliver a uniform dose in the entire body of the patient. Looking at 3D dose distributions for constant speed (CstSpeed) and variable speed (VarSpeed) translating couch TBI treatments, dose uniformity and the effect of body heterogeneities were evaluated. This study was based on retrospective dose calculations of 10 patients treated with a translating couch TBI technique. Dose distributions for CstSpeed and VarSpeed TBI treatments have been computed with Pinnacle3 treatment planning system in homogeneous (Homo) and heterogeneous (Hetero) dose calculation modes. A specific beam model was implemented in Pinnacle3 to allow an accurate dose calculation adapted for TBI special aspects. Better dose coverages were obtained with Homo/VarSpeed treatments compared to Homo/CstSpeed cases including smaller overdosage areas. Large differences between CstSpeed and VarSpeed dose calculations were observed in the brain, spleen, arms, legs, and lateral parts of the abdomen (differences between V100% mean values up to 57.5%). Results also showed that dose distributions for patients treated with CstSpeed TBI greatly depend on the patient morphology, especially for pediatric and overweight cases. Looking at heterogeneous dose calculations, underdosages (2%-5%) were found in high-density regions (e.g., bones), while overdosages (5%-15%) were found in low-density regions (e.g., lungs). Overall, Homo/CstSpeed and Hetero/VarSpeed dose distributions showed more hot spots than Homo/VarSpeed and were greatly dependent on patient anatomy. CstSpeed TBI treatments allow a simple optimization process but lead to less dose uniformity due to the patient anatomy. VarSpeed TBI treatments require more complex dose optimization, but lead to a better dose uniformity independent of the patient morphology. Finally, this study showed that heterogeneities should be considered in dose calculations in order to obtain a better optimization and, therefore, to improve dose uniformity.

Attenuator design for organs at risk in total body irradiation using a translation technique.

Total body irradiation (TBI) is an efficient part of the treatment for malignant hematological diseases. Dynamic TBI techniques provide great advantages (e.g., dose homogeneity, patient comfort) while overcoming treatment room space restrictions. However, with dynamic techniques come additional organs at risk (OAR) protection challenges. In most dynamic TBI techniques, lead attenuators are used to diminish the dose received by the OARs. The purpose of this study was to characterize the dose deposition under various shapes of attenuators in static and dynamic treatments. This characterization allows for the development of a correction method to improve attenuator design in dynamic treatments. The dose deposition under attenuators at different depths in dynamic treatment was compared with the static situation based on two definitions: the coverage areas and the penumbra regions. The coverage area decreases with depth in dynamic treatment while it is stable for the static situation. The penumbra increases with depth in both treatment modes, but the increasing rate is higher in the dynamic situation. Since the attenuator coverage is deficient in the dynamic treatment mode, a correction method was developed to modify the attenuator design in order to improve the OAR protection. The correction method is divided in two steps. The first step is based on the use of elongation charts, which provide appropriate attenuator coverage and acceptable penumbra for a specific depth. The second point is a correction method for the thoracic inclination, which can introduce an orientation problem in both static and dynamic treatments. This two steps correction method is simple to use and personalized to each patient's anatomy. It can easily be adapted to any dynamic TBI techniques.

A brief intervention for fatigue management in breast cancer survivors.

The purpose of this randomized control trial was to verify the effectiveness of a brief group intervention that combines stress management psycho-education and physical activity (ie, independent variable) intervention in reducing fatigue and improving energy level, quality of life (mental and physical), fitness (VO 2submax), and emotional distress (ie, dependent variables) in breast cancer survivors. This study applied Lazarus and Folkman stress-coping theoretical framework, as well as Salmon's unifying theory of physical activity. Eighty-seven French-speaking women who had completed their treatments for nonmetastatic breast cancer at a university hospital in Quebec City, Canada, were randomly assigned to either the group intervention (experimental) or the usual-care (control) condition. Data were collected at baseline, postintervention, and at 3-month follow-up. The 4-week group intervention was cofacilitated by 2 nurses. Results showed that participants in the intervention group showed greater improvement in fatigue, energy level, and emotional distress at 3-month follow-up, and physical quality of life at postintervention, compared with the participants in the control group. These results suggest that a brief psycho-educational group intervention focusing on active coping strategies and physical activity is beneficial to cancer survivors after breast cancer treatments.

Determinants of delay for breast cancer diagnosis.

BACKGROUND: A study was conducted to identify determinants of diagnostic delay in order to develop strategies to reduce the waiting time for breast cancer diagnosis. METHODS: A cohort of 696 women diagnosed with early breast cancer was recruited in two radiation oncology centers of Quebec, Canada, in 2002-2003. A structured questionnaire was administered to identify potential determinants of diagnostic delay. Dates for all of the breast procedures were extracted from medical records. "Diagnostic delay" was defined as a time interval of more than 5 weeks between the first breast specific procedure and the final diagnostic procedure. A logistic regression model was used to estimate adjusted odds ratios (OR) of diagnostic delay and their 95% confidence intervals (CI). RESULTS: The two main determinants of diagnostic delay were the medical indication for the breast investigation and the scheduling of the diagnostic procedures. Compared to screened women, those referred because of clinical findings had an OR of diagnostic delay of 0.34 (95% CI=0.22-0.54). Women who underwent breast procedures during visits on at least four separate days had an OR of 6.31 (95% CI=3.85-10.34) compared to those who completed their investigation during visits on at most two separate days. Women who had complementary procedures the day of the first procedure were less likely to experience a diagnostic delay (OR=0.51, 95% CI=0.31-0.82). Finally, diagnostic delay was also significantly associated with the interpretation of the first diagnostic procedure, type of final diagnostic procedure, size of tumor, and family income. CONCLUSIONS: This study suggests that a promising strategy for reducing the waiting time for breast cancer diagnosis is to better integrate the services during the investigation period.

The impact of the number of excised axillary nodes and of the percentage of involved nodes on regional nodal failure in patients treated by breast-conserving surgery with or without regional irradiation.

PURPOSE: After breast-conserving surgery, recommendations for regional nodal radiotherapy are usually based on the number of positive nodes. This number is dependent on the number of nodes removed during the axillary dissection. This study examines whether the percentage of positive nodes may help to select patients for regional radiotherapy. METHODS AND MATERIALS: A retrospective study was conducted on 1,372 T1-T2 node-positive breast cancer patients treated at L'Hôtel-Dieu de Québec Hospital between 1972 and 1997. RESULTS: Among the patients who did not receive regional radiotherapy, the percentage of involved nodes was significantly associated with axillary failure. Ten-year axillary control rates were 97% and 91% when the percentage of involved nodes was <50% and > or =50%, respectively (p = 0.007). In addition, regional radiotherapy is always significantly associated with a decrease in overall regional failure (axillary and/or supraclavicular), regardless of the percentage of involved nodes. However, regional radiotherapy reduced the axillary failure rate (2% vs. 9%, p = 0.007) only when more than a specific percentage of nodes was involved (> or =40% if N1-3 and > or =50% if N>3 nodes). CONCLUSIONS: The percentage of involved nodes should be taken into consideration in selecting patients for regional radiotherapy. Irradiation of the axilla should be reserved for patients with a specific ratio: >40% involved nodes if N1-3 and > or =50% involved nodes if N>3 nodes.

Impact of locoregional radiotherapy in node-positive patients treated by breast-conservative treatment.

PURPOSE: The aim of this study is to evaluate the impact of locoregional radiation in node-positive patients treated by tumorectomy and radiation therapy. METHODS: A retrospective study including all our 1368 T1-2 node-positive patients was conducted. Conservative surgery was followed by breast irradiation. Axillary and supraclavicular irradiation was left to the discretion of the treating radiation oncologist. RESULTS: In the group receiving locoregional radiation (472 patients), the 10-year regional control was 97% vs. 91% for the group receiving radiation to the breast only (896 patients) (p = 0.004). In a Cox model analysis, locoregional radiation is associated with a better regional control rate (hazard ratio: 0.27; 95% confidence interval: 0.13-0.54, p = 0.0001). Locoregional radiotherapy is associated with a better rate of locoregional control (hazard ratio: 0.56; 95% confidence interval: 0.38-0.8, p = 0.002). In particular, for the N>3 group, the substantial 10-year locoregional failure rate (26% with breast irradiation only) is cut by 50%. Locoregional radiotherapy, however, is not associated with a lower rate of distant metastases. CONCLUSION: Locoregional radiation decreases the rate of locoregional failure by nearly 50%. Locoregional radiotherapy should be considered for node-positive patients, especially if they have more than 3 positive nodes.