Takuya Nishimura - Academia.edu (original) (raw)

Uploads

Papers by Takuya Nishimura

Anticancer Research, Dec 1, 2013

Aim: To evaluate the incidence of rectal toxicity in patients undergoing hypofractionated (2.2 Gy... more Aim: To evaluate the incidence of rectal toxicity in patients undergoing hypofractionated (2.2 Gy) imageguided intensity-modulated radiotherapy (IG-IMRT) for prostate cancer. Patients and Methods: We examined 117 consecutive patients with prostate cancer who underwent IG-IMRT from June 2007 to July 2009. The median follow-up time was 32 months (range 20-42 months). The clinical target volume (CTV) consisted of the prostate and seminal vesicles, and the planning target volume (PTV) consisted of the CTV plus a 5-mm expansion, not avoiding the rectum. The PTV received a dose of 72.6-74.8 Gy in 33-34 fractions (2.2 Gy/fraction). Megavoltage computed tomographic (MVCT) scans were performed before each treatment and corrected to the registered position for planning CT scans using prostate soft tissue matching. Results: Late rectal bleeding of grades 1, 2, and 3 (Common Terminology Criteria for Adverse Events v3.0) occurred in 19 (16%), five (4%), and four (3%) patients, respectively. Late urinary toxicities of grades 1 and 2 occurred in five (4.3%) and eight (6.8%) patients, respectively. We found a paradoxically increased risk of rectal bleeding with more accurate irradiation of the rectum using soft tissue matching, whereas only a small percentage was reported in other IMRT series. Conclusion: IG-IMRT using daily MVCT scans allowed for exact dose delivery, which resulted in an increased rectal dose and exceptionally high incidence of rectal toxicity.

Journal of Medical Case Reports, 2014

Introduction: Radiotherapy is a standard treatment for prostate cancer, and image-guided radiothe... more Introduction: Radiotherapy is a standard treatment for prostate cancer, and image-guided radiotherapy is increasingly being used to aid precision of dose delivery to targeted tissues. However, precision during radiotherapy cannot be maintained when unexpected intrafraction organ motion occurs. Case presentation: We report our experience of internal organ motion caused by persistent gas production in a patient taking an alpha-glucosidase inhibitor. A 68-year-old Japanese man with prostate cancer visited our institution for treatment with helical tomotherapy. He suffered from diabetes mellitus and took an alpha-glucosidase inhibitor. Routine treatment planning computed tomography showed a large volume of rectal gas; an enema was given to void the rectum. Subsequent treatment planning computed tomography again showed a large volume of gas. After exercise (walking) to remove the intestinal gas, a third scan was performed as a test scan without tight fixation, which showed a sufficiently empty rectum for planning. However, after only a few minutes, treatment planning computed tomography again showed extreme accumulation of gas. Therefore, we postponed treatment planning computed tomography and consulted his doctor to suspend the alpha-glucosidase inhibitor, which was the expected cause of his persistent gas. Four days after the alpha-glucosidase inhibitor regimen was suspended, we took a fourth treatment planning computed tomography and made a treatment plan without gas accumulation. Thereafter, the absence of rectal gas accumulation was confirmed using daily megavolt computed tomography before treatment, and the patient received 37 fractions of intensity-modified radiotherapy at 74Gy without rectal gas complications. In this case study, the alpha-glucosidase inhibitor induced the accumulation of intestinal gas, which may have caused unexpected organ motion, untoward reactions, and insufficient doses to clinical targets. Conclusions: We suggest that patients who are taking an alpha-glucosidase inhibitor for diabetes should discontinue use of that particular medicine prior to beginning radiotherapy.

Anticancer Research, Jun 1, 2013

Anticancer Research, Dec 1, 2013

Aim: To evaluate the incidence of rectal toxicity in patients undergoing hypofractionated (2.2 Gy... more Aim: To evaluate the incidence of rectal toxicity in patients undergoing hypofractionated (2.2 Gy) imageguided intensity-modulated radiotherapy (IG-IMRT) for prostate cancer. Patients and Methods: We examined 117 consecutive patients with prostate cancer who underwent IG-IMRT from June 2007 to July 2009. The median follow-up time was 32 months (range 20-42 months). The clinical target volume (CTV) consisted of the prostate and seminal vesicles, and the planning target volume (PTV) consisted of the CTV plus a 5-mm expansion, not avoiding the rectum. The PTV received a dose of 72.6-74.8 Gy in 33-34 fractions (2.2 Gy/fraction). Megavoltage computed tomographic (MVCT) scans were performed before each treatment and corrected to the registered position for planning CT scans using prostate soft tissue matching. Results: Late rectal bleeding of grades 1, 2, and 3 (Common Terminology Criteria for Adverse Events v3.0) occurred in 19 (16%), five (4%), and four (3%) patients, respectively. Late urinary toxicities of grades 1 and 2 occurred in five (4.3%) and eight (6.8%) patients, respectively. We found a paradoxically increased risk of rectal bleeding with more accurate irradiation of the rectum using soft tissue matching, whereas only a small percentage was reported in other IMRT series. Conclusion: IG-IMRT using daily MVCT scans allowed for exact dose delivery, which resulted in an increased rectal dose and exceptionally high incidence of rectal toxicity.

Journal of Medical Case Reports, 2014

Introduction: Radiotherapy is a standard treatment for prostate cancer, and image-guided radiothe... more Introduction: Radiotherapy is a standard treatment for prostate cancer, and image-guided radiotherapy is increasingly being used to aid precision of dose delivery to targeted tissues. However, precision during radiotherapy cannot be maintained when unexpected intrafraction organ motion occurs. Case presentation: We report our experience of internal organ motion caused by persistent gas production in a patient taking an alpha-glucosidase inhibitor. A 68-year-old Japanese man with prostate cancer visited our institution for treatment with helical tomotherapy. He suffered from diabetes mellitus and took an alpha-glucosidase inhibitor. Routine treatment planning computed tomography showed a large volume of rectal gas; an enema was given to void the rectum. Subsequent treatment planning computed tomography again showed a large volume of gas. After exercise (walking) to remove the intestinal gas, a third scan was performed as a test scan without tight fixation, which showed a sufficiently empty rectum for planning. However, after only a few minutes, treatment planning computed tomography again showed extreme accumulation of gas. Therefore, we postponed treatment planning computed tomography and consulted his doctor to suspend the alpha-glucosidase inhibitor, which was the expected cause of his persistent gas. Four days after the alpha-glucosidase inhibitor regimen was suspended, we took a fourth treatment planning computed tomography and made a treatment plan without gas accumulation. Thereafter, the absence of rectal gas accumulation was confirmed using daily megavolt computed tomography before treatment, and the patient received 37 fractions of intensity-modified radiotherapy at 74Gy without rectal gas complications. In this case study, the alpha-glucosidase inhibitor induced the accumulation of intestinal gas, which may have caused unexpected organ motion, untoward reactions, and insufficient doses to clinical targets. Conclusions: We suggest that patients who are taking an alpha-glucosidase inhibitor for diabetes should discontinue use of that particular medicine prior to beginning radiotherapy.

Anticancer Research, Jun 1, 2013