Long-term safety of high-dose whole pelvic IMRT for high-risk localized prostate cancer through 10-year follow-up.

BACKGROUND: The aim of this study was to evaluate the long-term efficacy and safety of whole pelvic intensity-modulated radiation therapy with a simultaneous-integrated boost (WP-SIB-IMRT) for locally advanced prostate cancer (LAPCa). METHODS: All patients with cT3-4N0M0 prostate cancer treated with WP-SIB-IMRT between February 2006 and September 2009 at our institution were analyzed retrospectively. The prescribed dose was 78 Gy to the prostate and 58.5 Gy to the prophylactic pelvic lymph nodal area in 39 fractions delivered using the simultaneous-integrated boost technique. All patients received short-term neoadjuvant androgen-deprivation therapy alone (median 8.3 months). Propensity-score matching (PSM) analysis was performed to evaluate the additional benefit of prophylactic whole pelvic radiation therapy (WPRT), using the cohort of 203 LAPCa patients treated with prostate-only IMRT (PO-IMRT). RESULTS: In total, 47 consecutive patients were analyzed. The median estimated risk of pelvic lymph node involvement was 57.5%. The median follow-up period was 10.5 years. The 10 year prostate cancer-specific survival and biochemical failure (BF) rates were 92.2 and 54.8%, respectively. The 10 year cumulative incidence rates of ≥ grade 2 late genitourinary and gastrointestinal toxicities were 21.6 and 17.2%, respectively. From a total of 250 patients, PSM analysis identified 76 patients with similar characteristics, and no significant difference in BF rates was observed between WP-SIB-IMRT and PO-IMRT cohorts (p = 0.261). CONCLUSIONS: WP-SIB-IMRT for LAPCa was safe over long-term observation, although no clear benefit of WPRT was observed among our small and highly selected cohort. Regarding the additional efficacy of WPRT, further investigations are needed.

Clinical effect of multileaf collimator width on the incidence of late rectal bleeding after high-dose intensity-modulated radiotherapy for localized prostate carcinoma.

BACKGROUND: Several studies have confirmed a dosimetric advantage associated with use of a smaller leaf in intensity-modulated radiation therapy (IMRT). However, no studies have identified any clinical benefits. We investigated the effect of a smaller multileaf collimator (MLC) width on the onset of late rectal bleeding after high-dose prostate IMRT. MATERIALS AND METHODS: Two hundred and five prostate cancer patients were treated with a total dose of 78 Gy in 39 fractions by use of a dynamic MLC technique; however, two different MLC were used: a 10-mm-wide device and a 5-mm-wide device. Gastrointestinal toxicity and several clinical factors were assessed. RESULTS: The 5-year actuarial risk of grade 2 or higher rectal bleeding was 6.9 % for the 10-mm-wide group (n = 132) and 1.8 % for the 5-mm-wide group (n = 73) (p = 0.04). The median estimated rectal doses for the two groups were 55.1 and 50.6 Gy (p < 0.001), respectively. Univariate analysis showed that acute toxicity, rectal V30-60, median rectal dose, normal tissue complication probability (NTCP), and MLC type were significant predictive factors for late rectal toxicity. In multivariate analysis, acute toxicity and NTCP remained significant. CONCLUSION: In our planning approach for prostate IMRT, a decrease in MLC width from 10 to 5 mm contributed to further rectal dose reduction, which was the most important predictor of late rectal toxicity.

Long-term outcomes of intensity-modulated radiation therapy combined with neoadjuvant androgen deprivation therapy under an early salvage policy for patients with T3-T4N0M0 prostate cancer.

BACKGROUND: Long-term outcomes of dose-escalated intensity-modulated radiation therapy (IMRT) combined with neoadjuvant (NA) androgen deprivation therapy (ADT) under an early salvage policy in patients with locally advanced prostate cancer (LAPC) were evaluated. METHODS: Data from 120 patients with T3-T4N0M0 adenocarcinoma of the prostate treated with IMRT were analyzed. NA-ADT with a median duration of 6 months was provided in all cases. Seventy-eight Gy, at 2 Gy per fraction, was delivered to the prostate and seminal vesicles. Adjuvant ADT (A-ADT) was not provided for any patient following the completion of IMRT. Salvage ADT (S-ADT) commenced when PSA values >4 ng/ml. RESULTS: The median follow-up period was 97 months. S-ADT was initiated in 39 patients. The median PSA value at the initiation of S-ADT was 5.7 ng/ml. The 8-year biochemical relapse-free survival, prostate cancer-specific survival, overall survival and S-ADT-free rates were 53.2 % [95 % confidence interval (CI) 43.4, 62.1], 96.6 % (95 % CI 91.2, 98.7), 89.1 % (95 % CI 81.5, 93.7) and 66.6 % (95 % CI 60, 74.6), respectively. The estimated 8-year cumulative incidence rates of grade 2-3 late gastrointestinal, and grade 2-3 genitourinary toxicity were 7.6 and 10.7 %, respectively. No grade 4 toxicity was observed. CONCLUSIONS: High-dose IMRT, combined with NA-ADT for LAPC, was associated with favorable long-term disease-specific and overall survival outcomes, despite non-provision of A-ADT under the early S-ADT provision policy. This approach may represent a viable alternative to uniform provision of long-term A-ADT, because two-thirds of the patients maintained ADT-free status over an 8-year period after IMRT. Prospective trials will be required.

Ten-year outcomes of intensity-modulated radiation therapy combined with neoadjuvant hormonal therapy for intermediate- and high-risk patients with T1c-T2N0M0 prostate cancer.

BACKGROUND: We aimed to analyze the 10-year outcomes of intensity-modulated radiation therapy (IMRT) combined with neoadjuvant hormonal therapy (HT) for patients with intermediate- and high-risk T1c-T2N0M0 prostate cancer. METHODS: Fifty patients with T1c-T2N0M0 prostate cancer, who were treated with high-dose IMRT combined with neoadjuvant HT, were evaluated. Of these patients, 19 and 31 were classified into the intermediate- and high-risk groups, respectively. Neoadjuvant HT was administered over a median duration of 6 months; 74 and 78 Gy in 2 Gy per fraction were essentially delivered to the intermediate- and high-risk cases, respectively. Adjuvant HT was not administered to any of the patients after the completion of IMRT. RESULTS: Over a median follow-up period of 118 months, the 10-year prostate-specific antigen failure-free survival, prostate-specific antigen failure-free, salvage hormonal therapy-free, prostate cancer-specific survival, and overall survival rates were 70.2 %, 78.7 %, 89.2 %, 100 %, and 88.8 %, respectively. No grade 3 or higher acute or late toxicities were observed. The 10-year likelihoods of developing grade 2 late urinary and rectal toxicities were 13.7 % and 4.2 %, respectively. Compared with the outcomes of a cohort of historical controls who were locally irradiated with 70 Gy by three-dimensional conformal radiotherapy, the prostate-specific antigen failure-free rate was significantly better in the IMRT groups (78.7 % vs. 53.4 % at 10 years; p = 0.027). CONCLUSIONS: High-dose IMRT combined with neoadjuvant HT achieved not only high prostate-specific antigen control, but also excellent survival outcomes with acceptable morbidities, for a Japanese cohort of intermediate- and high-risk T1c-T2N0M0 prostate cancer patients, and these results warrant further investigation.

Long-term outcomes of dynamic conformal arc irradiation combined with neoadjuvant hormonal therapy in Japanese patients with T1c-T2N0M0 prostate cancer: case series study.

OBJECTIVE: There are few reports of the outcomes of external beam radiotherapy in Asian males with localized prostate cancer. The aim of this study is to evaluate the long-term outcomes of external beam irradiation using three-dimensional two-dynamic conformal arc therapy, combined with neoadjuvant hormonal therapy, in patients with T1c-T2N0M0 prostate cancer. METHODS: Between March 2003 and August 2007, 150 Japanese patients with T1c-T2N0M0 prostate cancer were definitively treated with three-dimensional two-dynamic conformal arc therapy. The median age, pretreatment prostate-specific antigen values and neoadjuvant hormonal therapy period were 73 years, 9.4 ng/ml and 6 months, respectively. In principle, 74 Gy was delivered to the planning target volume, although the total dose was reduced to 70 Gy in patients with unfavorable risk factors, such as severe diabetes mellitus or anticoagulant therapy. No adjuvant hormonal therapy was given to any patient. Salvage hormonal therapy was started when the prostate-specific antigen value exceeded 4 ng/ml in a monotonically increasing manner. RESULTS: The median follow-up period was 79 months. Salvage hormonal therapy was initiated in 10 patients and the median prostate-specific antigen value at the initiation was 4.7 ng/ml. The 5-year Kaplan-Meier estimates of the biochemical relapse-free survival rate, the salvage hormonal therapy -free rate and the overall survival rate were 83.3% (95% confidence interval = 77.1-89.6%), 94.3% (95% confidence interval = 90.4-98.1%) and 96.3% (95% confidence interval = 93.1-99.5%), respectively. The 5-year cumulative incidence rates of developing more than Grade 2 late rectal and urinary toxicities were 5.5 and 2.9%, respectively. CONCLUSIONS: Three-dimensional two-dynamic conformal arc therapy, with up to 74 Gy, in patients with T1c-T2N0M0 prostate cancer with neoadjuvant hormonal therapy was well tolerated and achieved good biochemical control and survival outcomes.

Safety and effectiveness of stereotactic body radiotherapy for a clinically diagnosed primary stage I lung cancer without pathological confirmation.

BACKGROUND: Pathological diagnosis fails in some pulmonary tumors, although they may be highly suspected to be primary lung cancer. We studied the outcome of stereotactic body radiotherapy for a clinically diagnosed primary stage I lung cancer without pathological confirmation. METHODS: The current study included 37 patients (39 lesions) treated with stereotactic body radiotherapy who were clinically diagnosed with primary stage I lung cancer between August 1998 and April 2009 at our hospital. Pulmonary tumors were highly suspected to be malignant from physical and imaging examinations. Biopsies were performed for 62 % of patients, although malignancy was not pathologically confirmed. In the other 38 % of patients, a biopsy was not feasible. Median age of the patients was 77 years. Median tumor diameter was 20 mm. A total median dose of 48 Gy was prescribed to the isocenter in four fractions. Median follow-up period was 39 months. RESULTS: The 3-year overall survival, local control, and regional-distant control were 74.2, 94.0, and 68.6 %, respectively. In patients with tumors ≤20 mm, overall survival and regional-distant control were significantly higher than in patients with tumors >20 mm (p ≤ 0.001), whereas no significant difference was observed regarding local control. No grade 3-5 adverse events possibly, probably, or definitely related to the treatment were observed. CONCLUSIONS: Stereotactic body radiotherapy is safe and effective for a clinically diagnosed primary stage I lung cancer when pathological diagnosis is difficult even with repeat biopsies, or a biopsy is not feasible for reasons of the patient's health condition or wishes.

Late recurrence of nonseminomatous germ cell tumor successfully treated with intensity-modulated radiation therapy.

We report the case of a 41-year-old man with a late recurrence of nonseminomatous germ cell tumor, which was successfully treated with intensity-modulated radiation therapy. For the residual retrocrural tumor invading the 11th and 12th thoracic vertebrae with an abnormal level of tumor marker (α-fetoprotein: 23.2 ng/ml) after salvage chemotherapy, chemotherapy could not be continued due to its neurotoxicity, and surgery could not be performed due to the location. In this situation, intensity-modulated radiation therapy achieved a complete response of tumor marker. The patient remained in complete clinical remission after 3 years. The efficacy of radiotherapy, especially intensity-modulated radiation therapy, for a nonseminomatous germ cell tumor is discussed.

Risk factors predicting the outcome of salvage radiotherapy in patients with biochemical recurrence after radical prostatectomy.

OBJECTIVES: Salvage radiotherapy is the only curative treatment for patients with prostate cancer showing biochemical progression after radical prostatectomy. In this study, we evaluated the clinicopathological parameters that influence the outcome of salvage radiotherapy. METHODS: Medical records of 49 patients who underwent salvage radiotherapy after radical prostatectomy from 1997 to 2008 at the Graduate School of Medicine, Kyoto University, were retrospectively reviewed. Radiotherapy was carried out with 66 Gy on the prostatic bed. RESULTS: Biochemical progression-free survival after salvage radiotherapy at 2, 5 and 7 years was 51.0%, 42.2% and 42.2%, respectively. Significant parameters predicting biochemical progression after salvage radiotherapy by Cox regression analysis were prostatectomy Gleason score sum ≥ 8 (hazard ratio 0.08; 95% confidence interval 0.03-0.22; P=0.001), prostate-specific antigen nadir after radical prostatectomy ≥ 0.04 ng/mL (hazard ratio 0.30; 95% confidence interval 0.13-0.69; P=0.005) and negative surgical margin (hazard ratio 0.28; 95% confidence interval 0.12-0.70; P=0.006). When the patients were subgrouped by these risk factors, the 5-year progression-free survival rates after salvage radiotherapy were 77.8%, 50.0% and 6.7% in patients with 0, 1 and ≥ 2 predictors, respectively. CONCLUSION: In order to discriminate favorable candidates for salvage radiotherapy, Gleason score of prostatectomy, prostate-specific antigen nadir after prostatectomy and positive surgical margin represent independent predictors. Thus, progression-free survival might be more precisely predicted according to the presence/absence of these risk factors. The significance of this risk classification should be confirmed by large prospective studies.

Ten-year outcomes of whole-pelvic intensity-modulated radiation therapy for prostate cancer with regional lymph node metastasis.

BACKGROUND: Management of pelvic node-positive prostate cancer has been challenging and controversial. We conducted a study to evaluate the outcomes of whole-pelvic (WP) simultaneous integrated boost (SIB) intensity-modulated radiation therapy (IMRT) combined with androgen deprivation therapy (ADT). METHODS: A total of 67 consecutive patients with cT1c-4N1M0 prostate cancer were definitively treated by WP SIB-IMRT. Neoadjuvant ADT (median: 8.3 months) was administered in all cases. WP SIB-IMRT was designed to simultaneously deliver 78, 66.3, and 58.5 Gy in 39 fractions to the prostate plus seminal vesicles, metastatic lymph nodes (LNs), and the pelvic LN region, respectively. Adjuvant ADT (median: 24.7 months) was administered in 66 patients. RESULTS: The median follow-up period was 81.6 months (range: 30.5-160.7). Biochemical relapse-free, overall, and prostate cancer-specific survival rates at 10 years were 59.8%, 79.6%, and 86.3%, respectively. Loco-regional recurrence was not observed. Being in International Society of Urological Pathology grade group 5 and having a posttreatment detectable nadir prostate-specific antigen (PSA) level (≥0.010 ng/ml) were significantly associated with worse prostate cancer-specific survival and progression of castration resistance. The 10-year cumulative incidence rates of grade 2 and 3 late toxicities were, respectively, 1.5% and 0% for genitourinary, 0% and 1.5% for gastrointestinal events. No grade 4 acute or late toxicities were observed. CONCLUSIONS: WP SIB-IMRT can be safely administered to patients with pelvic node-positive prostate cancer. Since grade group 5 and detectable nadir PSA levels are risks for castration resistance, we may need to increase the intensity of treatment for such cases.

Long-term outcomes of three-dimensional conformal radiation therapy combined with neoadjuvant hormonal therapy for Japanese patients with T1c-T2N0M0 prostate cancer.

BACKGROUND: The outcomes of three-dimensional conformal radiation therapy (3D-CRT) combined with neoadjuvant hormonal therapy (NAHT) in Japanese patients with T1c-T2N0M0 prostate cancer, with initiation of salvage hormonal therapy (SHT) at a relatively early phase, were analyzed. METHODS: Fifty-nine Japanese patients with T1c-T2N0M0 prostate cancer who received radical 3D-CRT between January 1999 and January 2003 were evaluated. The median age, initial prostate-specific antigen (PSA) level, and duration of NAHT were: 72 years, 9.4 ng/ml, and 6 months, respectively. Seventy Gy was given in 35 fractions confined to the prostate ± seminal vesicles. AHT was not administered after 3D-CRT in any patients. RESULTS: The median follow-up period was 89 months. The median PSA value at the time of initiation of SHT was 4.7 ng/ml (range 0.1-21.6 ng/ml). The overall, disease-specific, PSA failure-free (based on the Phoenix definition), and SHT-free survival rates at 8 years were 82.8% (95% confidence interval [CI] 72.4-93.2), 100%, 62.4% (47.1-77.8), and 82.6% (71.3-94.0), respectively. Only one patient developed grade 3 late toxicity. CONCLUSIONS: The PSA control rates in our series of Japanese patients with stage T1c-T2N0M0 prostate cancer treated with the standard dose of 3D-CRT combined with NAHT seemed at least comparable to those reported from Western countries; as well, the patients had excellent outcomes. The present outcomes can be used as basic data for evaluating the impact of dose escalation with intensity-modulated radiation therapy for Japanese patients with prostate cancer in the future.

Detailed dosimetric evaluation of intensity-modulated radiation therapy plans created for stage C prostate cancer based on a planning protocol.

BACKGROUND: Intensity-modulated radiation therapy (IMRT) has been employed as a precision radiation therapy with higher conformity to the target. Although clinical outcomes have been reported for many investigations, detailed treatment planning results have not been mentioned to date. The aim of this study was to evaluate the dose specifications of our IMRT treatment plans for locally advanced prostate cancer. METHODS: Seventy-seven clinically applied IMRT plans treated between September 2003 and December 2005, in which patients were irradiated with 78 Gy in the prone position, were retrospectively analyzed. Dosimetric data output from dose volume histograms were evaluated in detail. RESULTS: The mean dose ± standard deviation, homogeneity index, and conformity index to the planning target volume (PTV) were 78.3 ± 0.7 Gy (100.4 ± 0.9%), 13.7 ± 3.0, and 0.83 ± 0.04, respectively. For the clinical target volume, the mean dose was 80.3 ± 0.7 Gy (102.9 ± 0.9%).The V40, V60, and V70 Gy of the rectal wall were 58.3 ± 2.8, 29.6 ± 2.7, and 15.2 ± 3.0%, respectively. Planning difficulties were encountered in patients whose bowels were displaced downward, as constraints imposed by the bowel position altered the dose index of the PTV. In many cases, additional bowel optimization parameters were required to satisfy constraints for organs at risk. However, major deviation could be avoided by inverse planning with computer optimization. CONCLUSION: IMRT allowed the creation of acceptable and practical treatment plans for locally advanced prostate cancer. Reports regarding detailed dosimetric evaluations are mandatory for interpreting clinical outcomes in the future.

[Salvage hormonal therapy against recurrence after curative external beam radiotherapy for locally advanced prostate cancer at Kyoto University Hospital].

Fifty-three patients with biochemical relapse (BCR) after receiving external beam radiotherapy (EBRT) against locally advanced prostate cancer (stage III : International Union Against Cancer [UICC] 6th edition) between September 1997 and January 2006 at our institution, who were treated with salvage hormonal therapy (HTx), were followed for a mean period of 75.5 months. There was progression to castrationresistant prostate cancer (CRPC) during the follow-up period in 17 patients (32.0%). The median time to CRPC after initial HTx was 17 months. Univariate analysis revealed that time to BCR after EBRT was significantly associated with progression to CRPC (p＝0.022), while PSA-doubling time just before salvage HTx was marginally associated with irradiation dose (p＝0. 088, p＝0.128 respectively). Multivariate analysis showed that time to BCR after EBRT was the only significant predictor of progression to CRPC (p＝ 0.035, Hazard ratio ; 0.252, 95% confidence interval ; 0.070-0.905) conclusion, time to BCR after EBRT might be a good predictor for the efficiency of salvage HTx after EBRT against locally advanced prostate cancer.

A consensus-based guideline defining clinical target volume for primary disease in external beam radiotherapy for intact uterine cervical cancer.

OBJECTIVE: To develop a consensus-based guideline to define clinical target volume for primary disease (clinical target volume primary) in external beam radiotherapy for intact uterine cervical cancer. METHODS: The working subgroup of the JCOG Radiation Therapy Study Group began developing a guideline for primary clinical target volume in November 2009. The group consisted of 10 radiation oncologists and 2 gynecologic oncologists. The process started with comparing the contouring on computed tomographic images of actual cervical cancer cases among the members. This was followed by a comprehensive literature review that included primary research articles and textbooks as well as information on surgical procedures. Extensive discussion occurred in face-to-face meetings (three occasions) and frequent e-mail communications until a consensus was reached. RESULTS: The working subgroup reached a consensus on the definition for the clinical target volume primary. The clinical target volume primary consists of the gross tumor volume, uterine cervix, uterine corpus, parametrium, vagina and ovaries. Definitions for these component structures were determined. Anatomical boundaries in all directions were defined for the parametrium. Examples delineating these boundaries were prepared for the posterior border of the parametrium for various clinical situations (i.e. central tumor bulk, degree of parametrial involvement). CONCLUSIONS: A consensus-based guideline defining the clinical target volume primary was developed for external beam radiotherapy for intact uterine cervical cancer. This guideline will serve as a template for radiotherapy protocols in future clinical trials. It may also be used in actual clinical practice in the setting of highly precise external beam radiotherapy, including intensity-modulated radiotherapy.

Impact of double-balloon rectal catheter use in external-beam radiotherapy for prostate cancer.

BACKGROUNDS: Prostate motion and rectal sparing are important treatment strategy issues in external-beam radiotherapy for localized prostate cancer. To address these issues, we prospectively investigated the feasibility of using a double-balloon rectal catheter. METHODS: The rectal catheter has inner and outer balloons that wedge the anus between them. Computed tomography (CT) examinations with and without the catheter were conducted in seven patients with localized prostate cancer treated by external-beam radiotherapy. The rectal wall sparing effect was evaluated using virtual three-dimensional conformal radiotherapy plans in each arm. To evaluate interfractional prostate motion, each patient underwent a series of four CT examinations consisting of a planning CT followed by three additional series of CT with and without a catheter during the course of radiotherapy. RESULTS: Virtual plans demonstrated the reduction of the dose to the rectum by expanding the posterior wall to lie outside the high- to intermediate-dose area when a catheter was applied. Interfractional prostate motion in the anteroposterior direction was effectively reduced by catheter usage; the mean ± standard deviation (SD) of the displacement was 1.3 ± 0.9 mm with a catheter as compared to 2.8 ± 1.8 mm without a catheter (P = 0.014), and the maximum displacement was successfully suppressed to 3 mm with a catheter compared to 6 mm without a catheter. Systematic and random components were also reduced with the catheter. CONCLUSION: These results suggest the feasibility and clinical applicability of the double-balloon rectal catheter.

Long-term outcomes of three-dimensional conformal radiation therapy combined with neoadjuvant hormonal therapy in Japanese patients with locally advanced prostate cancer.

BACKGROUND: The outcomes of three-dimensional conformal radiation therapy (3D-CRT) combined with neoadjuvant hormonal therapy (NAHT) in Japanese patients with locally advanced prostate cancer who initiated salvage hormonal therapy (SHT) at a relatively early phase were evaluated. METHODS: Between April 1998 and April 2003, 70 Japanese patients with T3N0M0 prostate cancer who received radical 3D-CRT treatment were evaluated. The median age, initial prostate-specific antigen (PSA) level, and duration of NAHT were 73 years old, 26.3 ng/ml, and 4 months, respectively. Seventy grays were given in 35 fractions that were confined to the prostate and seminal vesicles. Adjuvant hormonal therapy was not administered after 3D-CRT in any of the cases. RESULTS: The median follow-up period was 64.9 months. The median PSA value at the time of initiation of SHT was 5.0 ng/ml (range 0.1-21.6 ng/ml). Overall, disease-specific, PSA failure-free (based on the Phoenix definition) and SHT-free survival rates at 5 years were 90.3% (95% CI 86.5-94.0), 96.5% (94.0-98.9), 60.5% (48.2-72.7), and 63.5% (57.2-69.8), respectively. Therefore, two-thirds of the patients were still hormone-free at 5 years. CONCLUSIONS: PSA control rates in our series of Japanese patients with stage T3N0M0 prostate cancer treated with the standard dose of 3D-CRT combined with NAHT seemed higher than expected. This approach involving 3D-CRT combined with NAHT with the initiation of SHT at PSA values of around 5 ng/ml may be one option for Japanese patients with locally advanced prostate cancer, although further prospective study is required to confirm the validity.

Impact of multileaf collimator width on intraprostatic dose painting plans for dominant intraprostatic lesion of prostate cancer.

The aim of this study was to investigate the impact of multileaf collimator width (MLC-W) on intraprostatic dose painting plans for prostate cancer.Prostate cancer maps based on the histopathological findings were superimposed onto simulation CT images. Clinical target volume (CTV) 1 was defined as the prostate and the base of the seminal vesicles, and CTV2 was defined as the dominant intraprostatic lesions. Planning target volume (PTV) 1 and PTV2 were delineated by adding 5 mm margins to CTV1 and CTV2, respectively. For each case, two dose painting plans were created to deliver 74 Gy to PTV1 and 84 Gy to PTV2 with dynamic multileaf collimator technique using two different MLCs: m3 (MLC-W: 3mm) and Millennium (5 mm). Plans were evaluated by comparing the conformation number (CN), a quantity that defines the degree of conformality.The CNs for plans using the m3 and Millennium were 0.68 and 0.67 for PTV1 and 0.59 and 0.58 for PTV2, respectively. The CNs tended to be higher for a thinner leaf width (p < 0.05).Dosimetric advantages associated with smaller leaves were observed. However, differences between 3 mm and 5 mm leaf width were relatively small, which suggested that 5 mm leaf width would be acceptable in dose painting plans for prostate cancer.

Stereotactic body radiotherapy for oligometastatic lung tumors.

PURPOSE: Since 1998, we have treated primary and oligometastatic lung tumors with stereotactic body radiotherapy (SBRT). The term "oligometastasis" is used to indicate a small number of metastases limited to an organ. We evaluated our clinical experience of SBRT for oligometastatic lung tumors. METHODS AND MATERIALS: A total of 34 patients with oligometastatic lung tumors were included in this study. The primary involved organs were the lung (n = 15), colorectum (n = 9), head and neck (n = 5), kidney (n = 3), breast (n = 1), and bone (n = 1). Five to seven, noncoplanar, static 6-MV photon beams were used to deliver 48 Gy (n = 18) or 60 Gy (n = 16) at the isocenter, with 12 Gy/fraction within 4-18 days (median, 12 days). RESULTS: The overall survival rate, local relapse-free rate, and progression-free rate at 2 years was 84.3%, 90.0%, and 34.8%, respectively. No local progression was observed in tumors irradiated with 60 Gy. SBRT-related pulmonary toxicities were observed in 4 (12%) Grade 2 cases and 1 (3%) Grade 3 case. Patients with a longer disease-free interval had a greater overall survival rate. CONCLUSION: The clinical result of SBRT for oligometastatic lung tumors in our institute was comparable to that after surgical metastasectomy; thus, SBRT could be an effective treatment of pulmonary oligometastases.

Geometrical differences in target volumes between slow CT and 4D CT imaging in stereotactic body radiotherapy for lung tumors in the upper and middle lobe.

Since stereotactic body radiotherapy (SBRT) was started for patients with lung tumor in 1998 in our institution, x-ray fluoroscopic examination and slow computed tomography (CT) scan with a rotation time of 4 s have been routinely applied to determine target volumes. When lung tumor motion observed with x-ray fluoroscopy is larger than 8 mm, diaphragm control (DC) is used to reduce tumor motion during respiration. After the installation of a four-dimensional (4D) CT scanner in 2006, 4D CT images have been supplementarily acquired to determine target volumes. It was found that target volumes based on slow CT images were substantially different from those on 4D CT images, even for patients with lung tumor motion no larger than 8 mm. Although slow CT scan might be expected to fare well for lung tumors with motion range of 8 mm or less, the potential limitations of slow CT scan are unknown. The purpose of this study was to evaluate the geometrical differences in target volumes between slow CT and 4D CT imaging for lung tumors with motion range no larger than 8 mm in the upper and middle lobe. Of the patients who underwent SBR between October 2006 and April 2008, 32 patients who had lung tumor with motion range no larger than 8 mm and did not need to use DC were enrolled in this study. Slow CT and 4D CT images were acquired under free breathing for each patient. Target volumes were manually delineated on slow CT images (TV(slow CT)). Gross tumor volumes were also delineated on each of the 4D CT volumes and their union (TV(4D CT)) was constructed. Volumetric and statistical analyses were performed for each patient. The mean +/- standard deviation (S.D.) of TV(slow CT)/TV(4D CT) was 0.75 +/- 0.17 (range, 0.38-1.10). The difference between sizes of TV(slow CT) and TV(4D CT) was not statistically significant (P = 0.096). A mean of 8% volume of TV(slow CT) was not encompassed in TV(4D CT) (mean +/- S.D. = 0.92 +/- 0.07). The patients were separated into two groups to test whether the quality of target delineation on slow CT scans depends on respiratory periods below or above the CT rotation time of 4 s. No significant difference was observed between these groups (P = 0.229). Even lung tumors with motion range no larger than 8 mm might not be accurately depicted on slow CT images. When only a single slow CT scan was used for lung tumors with motion range of 8 mm or less, 95% confidence values for additional margins for TV(slow CT) to encompass TV(4D CT) were 4.0, 5.4, 4.9, 5.1, 1.8, and 1.7 mm for lateral, medial, ventral, dorsal, cranial, and caudal directions, respectively.

Interinstitutional variations in planning for stereotactic body radiation therapy for lung cancer.

PURPOSE: The aim of this study was to assess interinstitutional variations in planning for stereotactic body radiation therapy (SBRT) for lung cancer before the start of the Japan Clinical Oncology Group (JCOG) 0403 trial. METHODS AND MATERIALS: Eleven institutions created virtual plans for four cases of solitary lung cancer. The created plans should satisfy the target definitions and the dose constraints for the JCOG 0403 protocol. RESULTS: FOCUS/XiO (CMS) was used in six institutions, Eclipse (Varian) in 3, Cadplan (Varian) in one, and Pinnacle3 (Philips/ADAC) in one. Dose calculation algorithms of Clarkson with effective path length correction and superposition were used in FOCUS/XiO; pencil beam convolution with Batho power law correction was used in Eclipse and Cadplan; and collapsed cone convolution superposition was used in Pinnacle3. For the target volumes, the overall coefficient of variation was 16.6%, and the interinstitutional variations were not significant. For maximal dose, minimal dose, D95, and the homogeneity index of the planning target volume, the interinstitutional variations were significant. The dose calculation algorithm was a significant factor in these variations. No violation of the dose constraints for the protocol was observed. CONCLUSION: There can be notable interinstitutional variations in planning for SBRT, including both interobserver variations in the estimate of target volumes as well as dose calculation effects related to the use of different dose calculation algorithms.

Correlation between urinary dose and delayed radiation cystitis after 78 Gy intensity-modulated radiotherapy for high-risk prostate cancer: A 10-year follow-up study of genitourinary toxicity in clinical practice.

PURPOSE: To investigate the factors associated with the risk of long-term genitourinary (GU) toxicity among high-risk prostate cancer (PC) patients treated with high-dose intensity-modulated radiotherapy (IMRT). METHODS AND MATERIALS: Between 2000 and 2011, PC patients treated with 78 Gy in 39 fractions delivered by IMRT combined with neo-adjuvant hormonal therapy were selected from among our database. GU toxicities and clinical factors, as well as separate anatomical urinary structures, were evaluated in terms of their associations. RESULTS: A total of 309 patients was included in this study. The median follow-up was 104 months (range: 24-143 months). The most frequently observed late grade ≥2 GU toxicity was hematuria (11.2%: 10-year actuarial risk) with radiation cystitis observed in the majority of patients. In univariate analysis, late grade ≥2 hematuria was associated with the exposure to doses >75 Gy (V75) of the bladder neck and V70 of the bladder wall, as well as with T stage. V75 of the bladder neck remained significant in multivariate analysis (p = 0.049). CONCLUSIONS: At the 10-year follow up of high-dose IMRT, a major concern was proved to be delayed cystitis related to the higher volume of bladder neck dose exposed excess over 75 Gy.