Deep inspiration breath-hold for patients with left-sided breast cancer - A one-fits-all approach? A prospective analysis of patient selection using dosimetrical and practical aspects.

OBJECTIVE: To prospectively analyze the feasibility of an algorithm for patient preparation, treatment planning, and selection for deep inspiration breath-hold (DIBH) treatment of left-sided breast cancer. METHODS: From February 2017 to July 2019, 135 patients with left-sided breast cancer were selected and prepared for radiotherapy in DIBH. 99 received radiotherapy for the breast alone and 36 for the breast including the lymphatic drainage (RNI). Treatment plans DIBH and free breathing (FB) were calculated. Dosimetrical analyses were performed, and criteria were defined to assess whether a patient would dosimetrically profit from DIBH. RESULTS: Of the 135 patients, 97 received a DIBH planning CT and 72 were selected for treatment in DIBH according to predefined criteria. When using DIBH, there was a mean reduction of the DmeanHeart of 2.8 Gy and DmeanLAD of 4.2 Gy. seven patients did not benefit from DIBH regarding DmeanHeart, 23 regarding DmeanLAD. For the left lung, the V20Gy was reduced by 4.9%, the V30Gy by 2.7% with 15 and 29 patients not benefiting from DIBH, respectively. In the 25 patients treated in FB, the benefit of DIBH would have been lower than for patients treated with DIBH (ΔDmeanHeart0.7 Gy vs 3.4 Gy). CONCLUSION: Dosimetrically, DIBH is no "one-fits-all" approach. However, there is a statistically significant benefit when looking at a larger patient population. DIBH should be used for treatment of left-sided breast cancer in patients fit for DIBH. ADVANCES IN KNOWLEDGE: This analysis offers a well-designed dosimetrical analysis in patients treated with DIBH radiotherapy in an "every day" cohort.

Changes of lung parenchyma density following high dose radiation therapy for thoracic carcinomas - an automated analysis of follow up CT scans.

BACKGROUND: An objective way to qualify the effect of radiotherapy (RT) on lung tissue is the analysis of CT scans after RT. In this analysis we focused on the changes in Hounsfield units (ΔHU) and the correlation with the corresponding radiation dose after RT. METHODS: Pre- and post-RT CT scans were matched and ΔHU was calculated using customized research software. ΔHU was calculated in 5-Gy-intervals and the correlation between ΔHU and the corresponding dose was calculated as well as the regression coefficients. Additionally the mean ΔHU and ΔHU in 5-Gy-intervals were calculated for each tumor entity. RESULTS: The mean density changes at 12 weeks and 6 months post RT were 28,16 HU and 32,83 HU. The correlation coefficient between radiation dose and ΔHU at 12 weeks and 6 months were 0,166 (p = 0,000) and 0,158 (p = 0,000). The resulting regression coefficient were 1439 HU/Gy (p = 0,000) and 1612 HU/Gy (p = 0,000). The individual regression coefficients for each patient range from - 2,23 HU/Gy to 7,46 HU/Gy at 12 weeks and - 0,45 HU/Gy to 10,51 HU/Gy at 6 months. When looking at the three tumor entities individually the highest ΔHU at 12 weeks was seen in patients with SCLC (38,13 HU) and at 6 month in those with esophageal carcinomas (40,98 HU). CONCLUSION: For most dose intervals there was an increase of ΔHU with an increased radiation dose. This is reflected by a statistically significant, although low correlation coefficient. The regression coefficients of all patients show large interindividual differences.

Changes in pulmonary function and influencing factors after high-dose intrathoracic radio(chemo)therapy.

PURPOSE: Using prospectively collected patient-related, dose-related, and pulmonary function test (PFT) data before radiotherapy (RT) and at several follow-up visits after RT, the time course of PFT changes after high-dose radio(chemo)therapy and influencing factors were analyzed. MATERIALS AND METHODS: From April 2012 to October 2015, 81 patients with non-small-cell lung carcinoma (NSCLC), small cell lung carcinoma (SCLC), or esophageal carcinoma where treated with high-dose radio(chemo)therapy. PFT data were collected before treatment and 6 weeks, 12 weeks, and 6 months after RT. The influence of patient- and treatment-related factors on PFT was analyzed. RESULTS: Mean forced expiratory volume in 1 s (FEV1) constantly declined during follow-up (p = 0.001). In total, 68% of patients had a reduced FEV1 at 6 months. Mean vital capacity (VC) didn't change during follow-up (p > 0.05). Mean total lung capacity (TLC) showed a constant decline after RT (p = 0.026). At 6 months, 60% of patients showed a decline in VC and 73% in TLC. The mean diffusion capacity for carbon monoxide (DLCO) declined at 6 and 12 weeks, but recovered slightly at 6 months (p < 0.0005). At 6 months, 86% of patients had a reduced DLCO. After treatment, the partial pressure of CO2 in the blood (pCO2) was increased and pO2 was decreased (p > 0.05). Only the pretreatment PFT classification had a significant influence on the post-RT FEV1. CONCLUSION: DLCO seems to be the most reliable indicator for lung tissue damage after thoracic RT. Ventilation parameters appear to be less reliable. Concerning patient- or treatment-related factors, no reliable conclusion can be drawn regarding which factors may be relevant.

Patient's quality of life after high-dose radiation therapy for thoracic carcinomas : Changes over time and influence on clinical outcome.

PURPOSE: Quality of life (QoL) is an important factor in patient care. This analysis is focused on QoL before and after radio(chemo)therapy in patients with thoracic carcinomas, as well as on its influence on clinical follow-up and survival, and the correlation with treatment-related toxicities. MATERIALS AND METHODS: The analysis included 81 patients with intrathoracic carcinoma receiving radio(chemo)therapy. For analysis of QoL, the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30) and the lung cancer-specific supplement (EORTC QLQ-LC13) were used. QoL data were collected before radiation treatment (RT), and 6 weeks, 12 weeks, 6 months, and 12 months after RT. Other factors were additionally analyzed, including clinical outcome, survival, and side effects. RESULTS: The functional scales showed maximum values or at least a recovery 12 weeks after RT. Symptoms with a high mean symptom score (> 40) at all appointments were fatigue, dyspnea, and coughing. Insomnia, peripheral neuropathy, appetite loss, dyspnea (from QLQ-LC13), and all pain parameters had an intermediate mean score (10-40). There were low mean scores of < 10 for nausea and vomiting, diarrhea, sore mouth, and hemoptysis. There was a significant correlation between clinical dysphagia and radiation pneumonitis with the associated symptom scales. None of the QoL scores had a significant influence on local and distant control or survival. CONCLUSION: 12 weeks after RT the QLQ-C30 functional scales show the highest scores or at least a temporary recovery. The symptom scales accurately reflect the common symptoms and treatment-related toxicities. QoL did not prove to be a significant predictor for local and distant control or survival.

A lot to a little or a little to a lot-which dose-volume relationship ensures the best clinical outcome in the high dose radiation therapy of thoracic tumors? A prospective approach.

BACKGROUND: The purpose of this prospective randomized trial is to determine which constellation of dose and corresponding volume of the lung tissue-either a lot to a little or a little to a lot-should be preferred to ensure the best possible outcome for patients with thoracic carcinomas. METHODS: From Apr 2012 to Oct 2015, 81 patients with NSCLC, SCLC or esophageal carcinoma were randomized and treated with either a 4-field-IMRT or a VMAT technique with or without additional chemotherapy. Data regarding clinical outcome, pulmonary function tests (PFT) and quality of life (QoL) was collected before RT, 6 weeks, 12 weeks and 6 months after treatment, QoL data additionally 1 year post RT. Follow up CTs were done 12 weeks and 6 months after RT. RESULTS: There is no significant difference regarding the local (P=0.954) and distant (P=0.206) outcome, side effects (all P>0.05) or survival (P=0.633) at any follow-up appointment. The comparison of the PFT shows a statistically significant difference for the DLCO 6 weeks post RT (P=0.028). All other parameters do not differ significantly at any follow up appointment. Regarding the QoL there is no statistically significant difference at any follow up appointment (P>0.1). There is a statistically significant difference between the mean density of the lung parenchyma at 12 weeks (P<0.0005) and 6 months post RT (P<0.0005). CONCLUSIONS: Since there is no significant and relevant difference between both treatment arms regarding PFT, clinical outcome and QoL it does not seem to relevant how the DVH is shaped exactly as long as established dose constraints for the organs at risk are respected. As to whether the difference between the CT density changes is clinically relevant further analysis is needed.

Rotational IMRT techniques compared to fixed gantry IMRT and tomotherapy: multi-institutional planning study for head-and-neck cases.

BACKGROUND: Recent developments enable to deliver rotational IMRT with standard C-arm gantry based linear accelerators. This upcoming treatment technique was benchmarked in a multi-center treatment planning study against static gantry IMRT and rotational IMRT based on a ring gantry for a complex parotid gland sparing head-and-neck technique. METHODS: Treatment plans were created for 10 patients with head-and-neck tumours (oropharynx, hypopharynx, larynx) using the following treatment planning systems (TPS) for rotational IMRT: Monaco (ELEKTA VMAT solution), Eclipse (Varian RapidArc solution) and HiArt for the helical tomotherapy (Tomotherapy). Planning of static gantry IMRT was performed with KonRad, Pinnacle and Panther DAO based on step&shoot IMRT delivery and Eclipse for sliding window IMRT. The prescribed doses for the high dose PTVs were 65.1Gy or 60.9Gy and for the low dose PTVs 55.8Gy or 52.5Gy dependend on resection status. Plan evaluation was based on target coverage, conformity and homogeneity, DVHs of OARs and the volume of normal tissue receiving more than 5Gy (V5Gy). Additionally, the cumulative monitor units (MUs) and treatment times of the different technologies were compared. All evaluation parameters were averaged over all 10 patients for each technique and planning modality. RESULTS: Depending on IMRT technique and TPS, the mean CI values of all patients ranged from 1.17 to 2.82; and mean HI values varied from 0.05 to 0.10. The mean values of the median doses of the spared parotid were 26.5Gy for RapidArc and 23Gy for VMAT, 14.1Gy for Tomo. For fixed gantry techniques 21Gy was achieved for step&shoot+KonRad, 17.0Gy for step&shoot+Panther DAO, 23.3Gy for step&shoot+Pinnacle and 18.6Gy for sliding window.V5Gy values were lowest for the sliding window IMRT technique (3499 ccm) and largest for RapidArc (5480 ccm). The lowest mean MU value of 408 was achieved by Panther DAO, compared to 1140 for sliding window IMRT. CONCLUSIONS: All IMRT delivery technologies with their associated TPS provide plans with satisfying target coverage while at the same time respecting the defined OAR criteria. Sliding window IMRT, RapidArc and Tomo techniques resulted in better target dose homogeneity compared to VMAT and step&shoot IMRT. Rotational IMRT based on C-arm linacs and Tomotherapy seem to be advantageous with respect to OAR sparing and treatment delivery efficiency, at the cost of higher dose delivered to normal tissues. The overall treatment plan quality using Tomo seems to be better than the other TPS technology combinations.