Abstract book - ESTRO meets Asia

S40 ESTRO meets Asia 2018

Abstract text Hematologic toxicity is an important side effect occurring in patients affected with pelvic malignancies, undergoing combined radio-chemotherapy, with consistent clinical meaningfulness. Since more than a half of bone marrow is comprised within the pelvic region, the radiation dose received by this functional compartment is crucial. Modern imaging modalities may provide a useful tool to identify bone marrow and new delivery technology may enhance the radiation oncologist’s possibility to selectively spare these structures, potentially decreasing acute hematologic toxicity profile in this setting. Correlation between dose to pelvic structures and acute hematologic toxicity has been studied in several oncological settings, mainly on a retrospective frame. Different dose metrics were found to be correlated including mean doses and different points within the dose- volume histogram ranging from low to medium-high doses. Several imaging modalities were used to identify bone marrow both morphological and functional. Several clinical endpoints were used. In general, accounting for bone marrow during the treatment planning process may be important to decrease the acute hematologic toxicity profile during concurrent chemo-radiation in anal cancer patients. The most appropriate strategy to address this issue need further investigation and deserve validation in a prospective clinical framework. SP-103 Challenge with carbon ion radiotherapy for gynecological cancers. T. Ohno 1 1 Gunma University, Gunma University Heavy Ion Medical Center, Maebashi, Japan Abstract text The standard of care for locally advanced cervical cancer is concurrent chemoradiotherapy (CCRT) consisting of external beam radiotherapy (EBRT), brachytherapy, and cisplatin-based chemotherapy. For brachytherapy, the implementation of 3D treatment planning and dose- volume histogram (DVH) parameter evaluation represents a major advancement of the last decade. Recent clinical studies with 3D image-guided brachytherapy (3D-IGBT) have shown increased local control and decreased late morbidities in patients with locally advanced cervical cancer, as compared with historical controls. On the other hand, large gross tumor volume at the time of brachytherapy, large high-risk clinical target volume, prolonged overall treatment period, and adenocarcinoma histology were associated with risk of local failure. Carbon ion radiotherapy (C-ion RT) offers excellent dose distribution, enabling a concentrated administration of a sufficient dose within a target volume while minimizing the dose in the surrounding normal tissues. Additionally, C-ion RT provides biological advantages not seen in proton or photon therapy, owing to high linear energy transfer (LET); C-ion RT induces increased double-strand DNA structures, causing irreversible cell damage independently of cell cycle phase or oxygenation, more so than does lower LET irradiation such as proton and photon therapy. Recently, by using high-resolution microscopy, we reported that complex clustered DNA double strand breaks were detected in a human cervical tumor clinically irradiated with C-ion RT but not in tumor tissue treated with X-rays (First-in-human). C-ion RT has been in use for more than 20-years in Japan and the efficacy and safety of this therapy, especially for photon-resistant tumors such as bone and soft tissue sarcoma, non-squamous cell carcinomas of the head and neck, pancreatic cancer, and rectal cancer is well accepted. For uterine cervical cancer, several dose escalation studies on C-ion RT have been performed without adoption of brachytherapy, mainly due to the lack

of 3D dose calculation and evaluation methods for brachytherapy. Carbon ion beams boost has been used in such studies instead of brachytherapy. The 2-year local control rates at the recommended dose level were 47% to 71% for adenocarcinoma/adenosquamous carcinoma, and 84% to 100% for bulky squamous cell carcinoma. After the emergence of 3D-IGBT, we initiated a new treatment combination of C-ion RT, 3D-IGBT, and concurrent weekly cisplatin in patients with locally advanced cervical cancer. In my talk, our challenges with carbon ion radiotherapy for gynecological cancers will be presented. Teaching lecture: Clinical manifestations of normal tissue damage SP-104 Clinical manifestations of normal tissue damage E. Hau 1 1 Sydney West Radiation Oncology Netword, Radiation Oncology, Sydney, Australia Abstract text This lecture will cover the acute and late clinical manifestations of radiation on normal tissues. The mechanisms of these manifestations will also be covered including discussion of potential modifiers of these responses. SP-105 Immobilisation/repositioning challenges in breast cancer I. Chitapanarux 1 1 Chiang Mai University, Division of Radiation Oncology- Department of Radiology Chiang Mai, Thailand Abstract text Breast is one of the organ that has daily set up errors (errors from patient positioning) which arise from the two main causes; the respiratory movement and the contour shifts due to the loose and pendulous property. Not only the good treatment planning but also the accuracy of patient repositioning and immobilization have been important in effective delivery breast radiotherapy. Since repositioning and immobilization are the area of the most inconsistency in the process of radiotherapy delivery. Many repositioning and immobilizing devices have been settled nowadays such as breast board (supine and prone), vacuum cushion, breast cup, or the latest device; a radiotherapy bra. Together with treatment verification process by using the image guidance, we can improve the accuracy and efficacy of radiotherapy in breast cancer. Symposium: Thorax high tech

SP-106 Modern approaches in locally advanced NSCLC U.Ricardi 1 1 University of Torino, Torino, Italy

Abstract not received

SP-107 Is there still a role for surgery in early stage lung cancer? B. Slotman 1 1 VU University Medical Center, Department of Radiation Oncology, Amsterdam, The Netherlands Abstract text Although surgery has widely been considered as the standard of care for patients with stage I non-small cell lung cancer (NSCLC), a substantial proportion of patients are unable or unwilling to undergo an operation, often due