Page 47 - 2014 Printable Abstract Book
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the dosimetric advantage of protons are marginal or only confined present in low-dose range. Lastly, it
will be important to develop cost-effective proton therapy technology.
(S704) Clinical Overview of Carbon Ion Radiotherapy. Hirohiko Tsujii, NIRS, Chiba, Japan
Rationale for using carbon-ions for cancer therapy lies primarily on improved dose distribution
and radiobiological characteristics of high-LET radiations, permitting the potential modification of
treatment efficacy to increase the differential in the biological response of tumor and the surrounding
normal tissues. There are currently 7 carbon-ion therapy facilities in operation in the world, in which more
than 10,000 patients have been treated with >70% of them treated at NIRS, Japan. Through clinical
experiences at NIRS and GSI, photon-resistant tumors have been successfully treated and a significant
reduction in overall treatment time has been achieved. NIRS started clinical trials in 1994 to evaluate the
clinical efficacy of carbon-ions generated from the HIMAC. Since then, trials have been carried out to
determine the tumor types that can be effectively treated with carbon-ions, to identify the optimum dose-
fractionation patterns, and to develop irradiation techniques for precise delivery of carbon-ions. In 2010,
a new treatment building was built to develop a pencil beam scanning and a compact rotating gantry.
Treatment with a scanning method was started in 2011, and its indications have been expanded to many
types of tumors. A total number of patients so far treated is more than 8,000. The experiences to date
indicate that C-ion RT is advantageous for the tumors that are generally photon-resistant and those
located in the vicinity of critical organs. These include skull base tumors, head and neck cancer, NSCLC,
HCC, pancreatic cancer, prostate cancer, post-operative recurrence of rectal cancer, bone/soft tissue
sarcoma, and uterine cervix adenocarcinoma. However, if the tumor infiltrates or originates in the
digestive tract, it was difficult to control them with C-ions. A significant reduction in fractions and
treatment time has been obtained with acceptable toxicities in most cases. For example, stage I lung
cancer and liver cancer can be treated with only one or two fractions, respectively. Even for prostate
cancers, 12 fractions in three weeks have been sufficient. Currently, treatment with pencil beam scanning
is applied to most tumors and will soon become available for treatment of a moving target.
S 08 TUMOR OXYGENATION: IMPACT ON CANCER THERAPY
Aberrant microenvironmental conditions in solid tumors negatively impact the response to
conventional anticancer therapies such as radiation and chemotherapy. Indeed the presence of hypoxia
in the primary tumor has been identified as a prognostic indicator of treatment outcome and several
clinical studies have shown excellent correlation between tumor therapy outcome and the distribution of
intra-tumor oxygen concentration. Hypoxic conditions can arise at the limits of oxygen diffusion from
blood vessels (diffusion or chronic hypoxia) or as a consequence of vascular collapse (perfusion or acute
hypoxia). Both types of hypoxia have been shown to upregulate key signaling pathways associated with
treatment resistance and metastasis; key reasons for treatment failures. Speakers at this symposium will
discuss (i) molecular approaches to identify critical insights into tumors that are hypoxic, (ii) the role of
factors associated with hypoxia-mediated treatment resistance and strategies directed at overcoming
such resistance, and (iii) how tumor microenvironmental conditions can favor cancer cell dissemination,
and the therapeutic potential of targeting strategies designed to impair the spread of cancer cells. Gaining
insights and better understanding of the molecular and physiologic facets of tumor hypoxia and their
45 | P a g e
will be important to develop cost-effective proton therapy technology.
(S704) Clinical Overview of Carbon Ion Radiotherapy. Hirohiko Tsujii, NIRS, Chiba, Japan
Rationale for using carbon-ions for cancer therapy lies primarily on improved dose distribution
and radiobiological characteristics of high-LET radiations, permitting the potential modification of
treatment efficacy to increase the differential in the biological response of tumor and the surrounding
normal tissues. There are currently 7 carbon-ion therapy facilities in operation in the world, in which more
than 10,000 patients have been treated with >70% of them treated at NIRS, Japan. Through clinical
experiences at NIRS and GSI, photon-resistant tumors have been successfully treated and a significant
reduction in overall treatment time has been achieved. NIRS started clinical trials in 1994 to evaluate the
clinical efficacy of carbon-ions generated from the HIMAC. Since then, trials have been carried out to
determine the tumor types that can be effectively treated with carbon-ions, to identify the optimum dose-
fractionation patterns, and to develop irradiation techniques for precise delivery of carbon-ions. In 2010,
a new treatment building was built to develop a pencil beam scanning and a compact rotating gantry.
Treatment with a scanning method was started in 2011, and its indications have been expanded to many
types of tumors. A total number of patients so far treated is more than 8,000. The experiences to date
indicate that C-ion RT is advantageous for the tumors that are generally photon-resistant and those
located in the vicinity of critical organs. These include skull base tumors, head and neck cancer, NSCLC,
HCC, pancreatic cancer, prostate cancer, post-operative recurrence of rectal cancer, bone/soft tissue
sarcoma, and uterine cervix adenocarcinoma. However, if the tumor infiltrates or originates in the
digestive tract, it was difficult to control them with C-ions. A significant reduction in fractions and
treatment time has been obtained with acceptable toxicities in most cases. For example, stage I lung
cancer and liver cancer can be treated with only one or two fractions, respectively. Even for prostate
cancers, 12 fractions in three weeks have been sufficient. Currently, treatment with pencil beam scanning
is applied to most tumors and will soon become available for treatment of a moving target.
S 08 TUMOR OXYGENATION: IMPACT ON CANCER THERAPY
Aberrant microenvironmental conditions in solid tumors negatively impact the response to
conventional anticancer therapies such as radiation and chemotherapy. Indeed the presence of hypoxia
in the primary tumor has been identified as a prognostic indicator of treatment outcome and several
clinical studies have shown excellent correlation between tumor therapy outcome and the distribution of
intra-tumor oxygen concentration. Hypoxic conditions can arise at the limits of oxygen diffusion from
blood vessels (diffusion or chronic hypoxia) or as a consequence of vascular collapse (perfusion or acute
hypoxia). Both types of hypoxia have been shown to upregulate key signaling pathways associated with
treatment resistance and metastasis; key reasons for treatment failures. Speakers at this symposium will
discuss (i) molecular approaches to identify critical insights into tumors that are hypoxic, (ii) the role of
factors associated with hypoxia-mediated treatment resistance and strategies directed at overcoming
such resistance, and (iii) how tumor microenvironmental conditions can favor cancer cell dissemination,
and the therapeutic potential of targeting strategies designed to impair the spread of cancer cells. Gaining
insights and better understanding of the molecular and physiologic facets of tumor hypoxia and their
45 | P a g e
