Interfractional Variations in the Setup of Pelvic Bony Anatomy and Soft Tissue, and Their Implications on the Delivery of Proton Therapy for Localized Prostate Cancer

Abstract In recent years, a novel technique has been employed to maintain a distance between the prostate and the rectum by transperineally injecting a hydrogel spacer (HS). However, the effect of HS on the prostate positional displacement is poorly understood, despite its stability with HS in place. In this study, we investigated the effect of HS insertion on the interfraction prostate motion during the course of proton therapy (PT) for Japanese prostate cancer patients. The study population consisted of 22 cases of intermediate-risk prostate cancer with 11 cases with HS insertion and 11 cases without HS insertion. The irradiation position and preparation were similar for both groups. To test for reproducibility, regular confirmation computed tomography (RCCT) was done four times during the treatment period, and five times overall [including treatment planning CT (TPCT)] in each patient. Considering the prostate position of the TPCT as the reference, the change in the center of gravity of the prostate relative to the bony anatomy in the RCCTs of each patient was determined in the left–right (LR), superior–inferior (SI) and anterior–posterior (AP) directions. As a result, no significant difference was observed across the groups in the LR and SI directions. Conversely, a significant difference was observed in the AP direction (P < 0.05). The proportion of the 3D vector length ≤5 mm was 95% in the inserted group, but 55% in the non-inserted group. Therefore, HS is not only effective in reducing rectal dose, but may also contribute to the positional reproducibility of the prostate.

Download Full-text

Intensity-Modulated Radiation Therapy, Proton Therapy, or Conformal Radiation Therapy and Morbidity and Disease Control in Localized Prostate Cancer

Yearbook of Urology ◽

10.1016/j.yuro.2012.06.022 ◽

2012 ◽

Vol 2012 ◽

pp. 80-81

Author(s):

A.S. Kibel

Keyword(s):

Prostate Cancer ◽

Radiation Therapy ◽

Disease Control ◽

Proton Therapy ◽

Intensity Modulated Radiation Therapy ◽

Localized Prostate Cancer ◽

Conformal Radiation Therapy ◽

Intensity Modulated

Download Full-text

Gastrointestinal toxicities following radiation therapy for localized prostate cancer.

Journal of Clinical Oncology ◽

10.1200/jco.2011.29.7_suppl.64 ◽

2011 ◽

Vol 29 (7_suppl) ◽

pp. 64-64

Author(s):

G. L. Lu-Yao ◽

S. Kim ◽

D. Moore ◽

W. Shih ◽

Y. Lin ◽

...

Keyword(s):

Prostate Cancer ◽

Radiation Therapy ◽

Proton Therapy ◽

Background Radiation ◽

Early Years ◽

Localized Prostate Cancer ◽

External Beam Radiation ◽

Beam Radiation ◽

Gi Toxicity ◽

3D Crt

64 Background: Radiation therapy (RAD) is commonly employed to treat localized prostate cancer; however, representative data regarding treatment related toxicities compared to conservative management (CM) is sparse. Methods: We performed a population-based cohort study, using Medicare claims data linked to the Surveillance, Epidemiology, and End Results data, to evaluate gastrointestinal (GI) toxicities in men aged 65-85 years treated with either primary RAD or CM for T1-T2 prostate cancer diagnosed in 1992-2005. In this study, only GI toxicities requiring interventional procedures occurring after 6 months of cancer diagnosis were included. Competing risk models were used with the following covariates: year of diagnosis, comorbidity, age, tumor stage, cancer grade, hormone use within 1 year of diagnosis, region, race, poverty and marital status. Results: Among 41,859 patients in this study, 28,021 patients received radiation therapy, 19,287 with external beam radiation therapy (EBRT) alone, and 5,138 with brachytherapy alone. The most common GI toxicity was GI bleeding or ulceration. GI toxicity rates were 6.1% after 3D-conformal therapy (3D-CRT), 2.8% after intensity modulated radiation therapy (IMRT), 2.6% after brachytherapy, 8.2% after proton therapy and 1.1% for CM patients. In the multivariate models, RAD group was associated with a higher hazard of GI toxicities (hazard ratio [HR] 4.68; 95% CI, 3, 93-5.58) than CM. Comparing to 3D-CRT, brachytherapy (HR 0.62; 95% CI, 0.51-0.75) and IMRT (HR 0.67; 95% CI, 0.55-0.82) are associated with a lower hazard of GI toxicities, while proton therapy is associated with a higher hazard of GI toxicities (HR 2.15; 95% CI, 1.45-3.17). Conclusions: Radiation therapy is associated with a higher risk of GI toxicities than CM. Among different modalities of radiation therapy, protons therapy is associated with the highest risk of GI toxicities, followed by 3D-CRT, IMRT, and brachytherapy. The increased GI toxicities for patients with proton therapy may reflect a learning curve in the early years. No significant financial relationships to disclose.

Download Full-text