Efficacy evaluation of 2D, 3D U-Net semantic segmentation and atlas-based segmentation of normal lungs excluding the trachea and main bronchi

This study aimed to examine the efficacy of semantic segmentation implemented by deep learning and to confirm whether this method is more effective than a commercially dominant auto-segmentation tool with regards to delineating normal lung excluding the trachea and main bronchi. A total of 232 non-small-cell lung cancer cases were examined. The computed tomography (CT) images of these cases were converted from Digital Imaging and Communications in Medicine (DICOM) Radiation Therapy (RT) formats to arrays of 32 × 128 × 128 voxels and input into both 2D and 3D U-Net, which are deep learning networks for semantic segmentation. The number of training, validation and test sets were 160, 40 and 32, respectively. Dice similarity coefficients (DSCs) of the test set were evaluated employing Smart SegmentationⓇ Knowledge Based Contouring (Smart segmentation is an atlas-based segmentation tool), as well as the 2D and 3D U-Net. The mean DSCs of the test set were 0.964 [95% confidence interval (CI), 0.960-0.968], 0.990 (95% CI, 0.989-0.992) and 0.990 (95% CI, 0.989-0.991) with Smart segmentation, 2D and 3D U-Net, respectively. Compared with Smart segmentation, both U-Nets presented significantly higher DSCs by the Wilcoxon signed-rank test (P < 0.01). There was no difference in mean DSC between the 2D and 3D U-Net systems. The newly-devised 2D and 3D U-Net approaches were found to be more effective than a commercial auto-segmentation tool. Even the relatively shallow 2D U-Net which does not require high-performance computational resources was effective enough for the lung segmentation. Semantic segmentation using deep learning was useful in radiation treatment planning for lung cancers.

Influence of chemoradiotherapy on nutritional status in locally advanced rectal cancer: Prospective multicenter study

OBJECTIVE

The aim of this study was to investigate the influence of chemoradiotherapy (CRT) on nutritional status and the association between changes in nutritional status and clinical outcomes (treatment completion, adverse events, perioperative complications, and relapse-free survival [RFS]) in patients with locally advanced rectal cancer (LARC).

METHODS

In this multicenter, phase II study, 41 patients with LARC underwent CRT for 5 wk, followed by a 6- to 8-wk interval before surgery. Body weight, body mass index (BMI), lean body mass, serum albumin, and prealbumin levels were measured before (pre-), during, and after CRT, and before surgery. Changes in these data and scores on the Malnutrition Universal Screening Tool (MUST) were calculated based on pre-CRT status.

RESULTS

Twelve patients (29.3%) experienced body weight loss (BWL) ≥5% (defined as malnutrition) after CRT (P < 0.001) and before surgery (P = 0.035). Significant changes were seen in serum albumin levels and BMI during and after CRT (P < 0.001), and in MUST scores after CRT (P = 0.003) and before surgery (P = 0.035). Treatment completion was significantly associated with BWL (P = 0.028), MUST score (P = 0.013), and decreased serum albumin level (P = 0.001) after CRT. Regarding adverse events, MUST score before surgery (P = 0.009) and serum albumin level after CRT (P = 0.002) were significantly associated with diarrhea severity. Serum albumin level during CRT was associated with the onset of neutropenia (P = 0.005). No association was found between BWL and RFS.

CONCLUSIONS

These findings suggest that malnutrition and changes in nutritional status are not only commonly observed after CRT, but also associated with treatment completion and adverse events.

Radiotherapy for localized sebaceous carcinoma of the eyelid: a retrospective analysis of 83 patients

The current study retrospectively analyzed the results of radiotherapy for clinically localized sebaceous carcinoma of the eyelid.We reviewed records of 83 patients with histologically confirmed sebaceous carcinoma who were treated radiotherapeutically between 1983 and 2015. Sixty-five patients (78%) were initially treated with radiotherapy of curative intent, while the remaining 18 patients underwent postoperative radiotherapy due to tumor recurrence or positive surgical margins. Thirty-seven patients belonged to T1-2, while 46 belonged to T3-4. All 83 patients were treated with radiotherapy with a median radiation dose of 60 Gy. The median follow-up period was 92.1 months (range, 2.8-310.3 months). At the time of analysis, 13 patients (15.1%) died, and 36 patients (43.3%) had local recurrence. The 7-year overall survival, freedom from neck lymph node recurrence, and local control (LC) rates for all patients were 83.5%, 75.5%, and 52.3%, respectively. Patients with a tumor size ≤10 mm had a higher 7-year LC rate than those with a tumor size >10 mm (58.8% vs 46.6%, P = 0.054). Neck lymph node recurrence was observed in 17 patients (20%) and significantly related to the tumor size. Late toxicity of an eyelid dysfunction of grade 3 was observed in 1 patient with T3 tumor. Radiotherapy for sebaceous carcinoma of the eyelid is a reasonable alternative to surgical resection for tumors <10 mm in size with few severe complications, while larger tumors should be treated with surgery if feasible.

Pleural contact decreases survival in clinical T1N0M0 lung cancer patients undergoing SBRT

BACKGROUND

Clinical staging, as used for patients treated with stereotactic body radiotherapy (SBRT) for early-stage lung cancer, inadequately accounts for pleural invasion, which is a pathologic criteria. Considering the current situation, we analyzed effects of relationships between tumors and the pleura on treatment outcomes of SBRT for early-stage lung cancer.

MATERIALS AND METHODS

Among consecutive patients treated with SBRT between 2006 and 2017, we retrospectively identified non-small cell lung cancer patients with primary tumor diameters ≤4 cm and N0M0. The relationships between tumors and the pleura were investigated. The effects of these findings on treatment outcomes were analyzed.

RESULTS

We identified 386 patients which met the inclusion criteria. Among these patients, 323 patients were with tumors of 0.1-3.0 cm (T1-size), and 63 patients were with tumors of 3.1-4.0 cm (T2a-size). Among patients with T1-size tumors, 120, 134, and 23 had findings of pleural contact, pleural indentation, and pleural thickening, respectively. When we divided T1-size patients into 2 groups based on pleural contact (contact- or contact+), the 3-year cause-specific mortality and overall survival in patients with T1-size & contact+ were significantly worse than those in patients with T1-size & contact- (17.6% (95% confidence interval (CI), 10.7-25.9%) vs. 6.6% (95% CI, 3.5-11.1%), p < 0.01), and 58.2% (95% CI, 47.6-67.5%) vs. 77.6% (95% CI, 70.5-83.2%), p < 0.01). Local recurrence, regional recurrence, pleural cavity recurrence, and distant metastasis were associated with worse cause-specific mortality and overall survival. On multivariate analysis, pleural contact was associated with cause-specific mortality (hazard ratio (HR), 1.96; 95% CI, 1.09-3.52; p = 0.03) and overall survival (HR, 1.59; 95% CI, 1.08-2.34; p = 0.02).

CONCLUSION

Pleural contact in clinical T1N0M0 lung cancer patients was associated with significantly worse survivals.

A Highly Advanced Gastric Cancer Maintaining a Clinical Complete Response after Chemoradiotherapy Comprising S-1 and Cisplatin

We report a patient with highly advanced gastric carcinoma who was treated successfully with chemoradiotherapy (CRT) comprising S-1 and cisplatin. The patient was a 71-year-old male who was diagnosed with advanced gastric carcinoma by esophagogastroduodenoscopy (EGD) by medical examination. EGD demonstrated type 3 advanced gastric carcinoma in the posterior wall of the upper gastric body. An abdominal computed tomography (CT) scan showed that the gastric wall was thickened due to gastric primary tumor, and large lymph nodes (LNs) including the lesser curvature LN, anterosuperior LN along the common hepatic artery and some para-aortic LNs were detected. The patient was diagnosed with stage IV advanced gastric carcinoma according to the Japanese classification of gastric carcinoma (cT4a, cN3, cM1 [para-aortic LN], cStage IV). Preoperative CRT was carried out in an attempt to downstage the disease. Remarkable reduction of the primary tumor and metastatic LNs was observed after initial CRT, and radiological examination determined that a partial response had been achieved. Adverse effects included grade 2 anorexia and grade 3 ALP elevation (919 U/ml). No grade 4 or more severe adverse event was observed. After CRT, although we recommended curative surgery, the patient refused surgical treatment and opted for conservative treatment. Thus, we continued S-1 oral administration for 1 year. Five months after beginning CRT, upper endoscopy showed that the tumor had maintained regression and scar formation, in which no cancer cells were detected by endoscopic biopsy. The patient is doing well and has maintained a clinical complete response for more than 42 months without curative surgery. CRT could be considered as an option for treatment of patients with locally advanced gastric carcinoma diagnosed as unresectable, or for those who refuse surgical treatment.

Low-Dose Induction Radiotherapy for Stomach Conservation in Patients with Massive Gastric Lymphoma

Low-dose induction radiotherapy was performed in 4 patients with massive gastric lymphoma in order to treat the disease without gastrectomy. Following the radiotherapy, gastric lesions had shrunk considerably without any complications. Standard chemotherapy and/or radiotherapy could then be performed safely, and stomach conservation could be achieved in all 4 patients.

Long-term results of concurrent chemoradiotherapy with daily-low-dose continuous infusion of 5-fluorouracil and cisplatin (LDFP) for Stage I-II esophageal carcinoma

We investigated long-term treatment outcomes and the feasibility of chemoradiotherapy consisting of daily-low-dose 5-fluorouracil and cisplatin (LDFP) chemotherapy plus radiotherapy for Stage I-II squamous cell esophageal cancer. Treatment records from the 2000 through 2008 period were reviewed retrospectively. Fractionated radiotherapy was performed with a total dose of 60 Gy delivered in 2 Gy per fraction. LDFP chemotherapy, as continuous infusion of 200 mg/m2 5-fluorouracil combined with one hour infusion of 4 mg/m2 cisplatin, was administered on the same days as radiotherapy. Survival was calculated by the Kaplan-Meier method. Survival, responses, failure patterns, and toxicities were evaluated. Seventy-six (47 stage I and 29 stage II) patients were analyzed with a median follow-up of 93.6 months. The 8-year overall survival (OS), progression-free survival (PFS) and cause-specific survival (CSS) rates were 63.4%, 49.8%, and 76.7%, respectively. The 8-year OS, PFS, and CSS for stage I and stage II patients were 71.0%/56.1%/82.9% and 45.2%/40.2%/66.6%, respectively. Sixty-eight patients (89.5%) completed the treatment regimen. A complete response (CR) was achieved in 68 patients (89.5%). Twenty-five patients (36.8%) experienced recurrence after CR. The failure patterns were (overlap included): local failure (n = 12), nodal metastasis (n = 12), distant metastasis (n = 3), details unknown (n = 2). Salvage therapy was performed for local failure; endoscopic therapy (n = 7) or surgery (n = 2). Six patients remain alive without relapse after salvage endoscopic therapy. Major Grade 3 or higher acute adverse events were leukopenia (22%), anorexia (17%), and esophagitis (11%). Major late toxicities (Grade 3 or 4) involved pericardial effusion (12%), pleural effusion (4%), and esophageal stenosis (3%). Chemoradiotherapy with LDFP provided favorable long-term survival with acceptable toxicity for Stage I-II squamous cell esophageal cancer. The tumor response was excellent, but close endoscopic follow-up is essential for detecting and treating local recurrence.

Prostate-specific antigen nadir within 12 months as an early surrogate marker of biochemical failure and distant metastasis after low-dose-rate brachytherapy or external beam radiotherapy for localized prostate cancer

Prostate-specific antigen nadir (nPSA) after radiotherapy for localized prostate cancer has been investigated as a predictor. However, nPSA usually requires several years, limiting its clinical utility. We investigated the significance of nPSA within 12 months (nPSA12) after low-dose-rate prostate brachytherapy (LDR-PB) or external beam radiotherapy (EBRT) on treatment outcomes. Between 2006 and 2014, 663 patients with prostate cancer were treated with LDR-PB or EBRT at two institutions. Four hundred and seventy-four men received LDR-PB and 189 men received EBRT, without androgen deprivation therapy. The Kaplan-Meier method was used for biochemical failure (BF)-free survival (BFFS) and distant metastasis (DM)-free survival (DMFS) analyses, and multivariable Cox regression analysis was performed. The median follow-up was 61.3 months. The median nPSA12 in the LDR-PB and EBRT cohorts was 0.7 and 1.0 ng/mL, respectively. The 7-year BFFS and DMFS rates in LDR-PB patients with nPSA12 ≤ 0.7 ng/mL were 99.1% and 99.5%, respectively; when nPSA12 was >0.7 ng/mL, they were 90.2% and 94.8%, respectively. In EBRT patients with nPSA12 ≤ 1.0 ng/mL, BFFS and DMFS rates were 85.4% and 98.5%, respectively; when nPSA12 was >1.0 ng/mL, they were 67.1% and 87.2%, respectively. nPSA12 was an independent predictor of BF and DM in both cohorts (LDR-PB, P = 0.004 and 0.020, respectively; EBRT, P = 0.005 and 0.041, respectively). The nPSA12 after LDR-PB or EBRT is significantly associated with treatment outcomes of prostate cancer. Higher nPSA12 may identify patients at high risk of relapse who might benefit from salvage treatment.

Long-term Clinical Results of Concurrent Chemoradiotherapy for Patients with Cervical Esophageal Squamous Cell Carcinoma

BACKGROUND/AIM

We assessed the efficacy and toxicity of concurrent chemoradiotherapy (CCRT) in patients with squamous cell carcinoma of the cervical esophagus.

PATIENTS AND METHODS

We retrospectively analyzed 37 patients treated with definitive CCRT. The patients received radiotherapy at a fraction dose of 2 Gy (total; 60 or 70 Gy) and concurrent chemotherapy. Adjuvant chemotherapy consisted of 1 to 2 cycles of 5-fluorouracil plus cisplatin or nedaplatin.

RESULTS

The median follow-up was 119.0 months, the 10-year overall survival, progression-free survival and laryngectomy-free survival rates were 35.6, 19.9 and 30.2% respectively. In the univariate analysis, T stage (T4 vs. T1-3) was the only prognostic factor for PFS. The most common acute toxicity was leukocytopenia (Grade 3; 27%). As for late toxicities, 4 patients (11%) developed Grade 2 or 3 esophageal strictures.

CONCLUSION

The results of this study demonstrated that CCRT yielded satisfactory clinical outcomes with acceptable toxicities.

Quantitative analysis of genitourinary toxicity after iodine-125 brachytherapy for localized prostate cancer: Followup of the International Prostate Symptom Score and Overactive Bladder Symptom Score

PURPOSE

To analyze genitourinary toxicity by followup of the International Prostate Symptom Score (IPSS) and Overactive Bladder Symptom Score (OABSS) after prostate brachytherapy.

METHODS AND MATERIALS

Six hundred eighty patients were treated with iodine-125 brachytherapy for localized prostate cancer. IPSS, OABSS, and two categories of IPSS questions (storage symptom score [IPSS-S] and voiding symptom score [IPSS-V]) were evaluated.

RESULTS

The median followup was 54 months (range, 24-108). All scales showed rapid increases followed by gradual decreases. The median times to IPSS peak and resolution were 1 and 6 months, respectively. The resolution rates of IPSS, IPSS-S, IPSS-V, and OABSS at the last followup were 84.2%, 86.3%, 89.5%, and 83.0%, respectively. The difference between IPSS baseline and peak was greater for larger preimplant prostate volumes (≥25 mL, p = 0.004). The time to resolution was longer for higher biologic effective dose (BED) (≥210 Gy, p = 0.019 [IPSS]), in those with larger prostate volumes (≥25 mL, p = 0.025 [OABSS]), in younger patients (younger than 70 years, p = 0.043 [IPSS-S]), and in those with androgen deprivation therapy (ADT) use (p = 0.049 [IPSS-V]). Urge incontinence, included in the OABSS, was observed more commonly in older patients (75 years and older, p = 0.018), with ADT use (p < 0.001), and for higher BED (≥210 Gy, p = 0.006).

CONCLUSIONS

The IPSS and OABSS showed similar patterns of change. Urinary symptoms improved more rapidly in those with high baseline IPSS levels. The OABSS was useful for following urinary symptoms after prostate brachytherapy. Age, ADT use, preimplant prostate volume, and BED were significantly associated with urinary outcomes.

Stereotactic body radiotherapy for operable early-stage non-small cell lung cancer

PURPOSE

To analyze outcomes of stereotactic body radiotherapy (SBRT) for operable patients with early-stage non-small cell lung cancer (NSCLC) and to evaluate factors associated with outcomes.

METHODS

We retrospectively analyzed operable patients with NSCLC, staged as cT1-2N0M0, treated with SBRT between 2006 and 2015. Both biopsy-proven and clinically diagnosed NSCLC were included. Local control and survival rates were calculated and compared between subsets of patients. We investigated factors associated with outcomes.

RESULTS

We identified 88 operable patients among 661 patients with cT1-2N0M0 NSCLC. The median age was 79 years (range: 55-88). The median follow-up time after SBRT was 40 months (range: 4-121). Fifty-nine patients had been pathologically diagnosed and the other 29 had been clinically diagnosed as having NSCLC. Local control, cause-specific survival (CSS) and overall survival (OS) at 3 years were 91%, 97% and 90% for T1, and 100%, 82% and 74% for T2, respectively. The CSS and OS at 3 years were 100% and 100% for GGO and 83% and 59% for solid tumors, respectively (p=0.005). On univariate analysis, age and T stage were significantly associated with CSS, and age, the Charlson Comorbidity Index (CCI), and opacity were significantly associated with OS. On multivariate analysis, age and CCI were significantly associated with OS. As for toxicities, Grades 0, 1, 2 and 3 radiation pneumonitis occurred in 37.5%, 47.7%, 13.6% and 1.1% of patients, respectively. No Grade 4 or 5 radiation pneumonitis occurred, and no other toxicities of Grade 2 or above were observed.

CONCLUSION

Outcomes of SBRT for operable early stage NSCLC were as good as previous SBRT and surgery studies. Further investigation for selecting good SBRT candidates is warranted in high-risk operable patients.

Influence of backscatter radiation on cranial reconstruction implants

OBJECTIVE

We aimed to evaluate backscatter dose variations in different cranial bone implant materials in an experimental model designed to simulate post-operative radiotherapy.

METHODS

We assessed the radiation backscatter doses associated with sheet- and mesh-type titanium plates and hydroxyapatite (HAP) samples (porosity: 35%, 50% and 85%). The samples were irradiated with 6- and 10-MV photon beams from a linear accelerator. Measurements were obtained using an ionization chamber and radiochromic films cut from the same batch.

RESULTS

At 6 MV, the titanium sheet showed the highest peak for backscattered radiation, followed by (in decreasing order) HAP30%, HAP50%, titanium mesh and HAP85%. At 10 MV, HAP30% showed the highest peak, followed by HAP50%, titanium sheet, titanium mesh and HAP85%. The peaks were at different depths in the titanium and HAP samples. The thickness of the human scalp is approximately 7 mm; therefore, measurements were obtained 0-7 mm above the implants to assess the likely dose on the scalp. A comparison of the maximum dose on the scalp showed the titanium sheet had the highest dose at both 6 and 10 MV.

CONCLUSION

The backscatter dose differed with the density of the material and the backscatter depth was different for each material. Advances in knowledge: Ulcer formation due to radiotherapy after brain tumour depends on not only radiation but also the implant material. Therefore, the density and type of implant material should be considered when planning radiotherapy and selecting bone reconstruction materials.

Stereotactic body radiotherapy for T3 and T4N0M0 non-small cell lung cancer

To evaluate the outcomes and feasibility of stereotactic body radiotherapy (SBRT) for cT3 and cT4N0M0 non-small cell lung cancer (NSCLC), 25 patients with localized primary NSCLC diagnosed as cT3 or cT4N0M0, given SBRT between May 2005 and July 2013, were analyzed. All patients had inoperable tumors. The major reasons for tumors being unresectable were insufficient respiratory function for curative resection, advanced age (>80 years old) or technically inoperable due to invasion into critical organs. The median patient age was 79 years (range; 60-86). The median follow-up duration was 25 months (range: 5-100 months). The 2-year overall survival rates for T3 and T4 were 57% and 69%, respectively. The 2-year local control rates for T3 and T4 were 91% and 68%, respectively. As for toxicities, Grade 0-1, Grade 2 and Grade 3 radiation pneumonitis occurred in 23, 1 and 1 patient, respectively. No other acute or symptomatic late toxicities were reported. Thirteen patients who had no local, mediastinal or intrapulmonary progression at one year after SBRT underwent pulmonary function testing. The median variation in pre-SBRT and post-SBRT forced expiratory volume in 1 s (FEV1) values was -0.1 (-0.8-0.8). This variation was not statistically significant (P = 0.56). Forced vital capacity (FVC), vital capacity (VC), %VC and %FEV1 also showed no significant differences. SBRT for cT3 and cT4N0M0 NSCLC was both effective and feasible. Considering the favorable survival and low morbidity rate, SBRT is a potential treatment option for cT3 and cT4N0M0 NSCLC.

Prospective study of direct radiation exposure measurements for family members living with patients with prostate (125)I seed implantation: Evidence of radiation safety

PURPOSE

To broaden the current understanding of radiation exposure and risk and to provide concrete evidence of radiation safety related to (125)I seed implantation.

METHODS AND MATERIALS

Direct radiation exposure measurements were obtained from dosimeters provided to 25 patients who underwent (125)I seed implantation, along with their family members. The estimated lifetime exposure dose and the precaution time for holding children near the patient's chest were calculated in two study periods.

RESULTS

During the first and second study period, the mean estimated lifetime exposure doses were, respectively, 7.61 (range: 0.45, 20.21) mSv and 6.84 (range: 0.41, 19.20) mSv for patients, and 0.19 (range: 0.02, 0.54) mSv and 0.25 (range: 0.04, 1.00) mSv for family members. The mean ratios of first and second period measurements were 1.05 (range: 0.44, 3.18) for patients and 1.82 (range: 0.21, 7.04) for family members. The corresponding absolute differences between first and second period measurements were -0.77 (range: -11.40, 7.63) mSv and 0.06 (range: -0.26, 0.79) mSv, respectively. Assuming a dose limit of 1 mSv, the precaution times for holding a child every day of the first and second periods were 250.9 (range: 71.3, 849.4) min and 275.2 (range: 75.0, 883.4) min, respectively. Assuming a dose limit of 0.5 mSv, the corresponding precaution times were 179.0 (range: 35.6, 811.5) min and 178.9 (range: 37.5, 1131.8) min, respectively.

CONCLUSIONS

Our study demonstrated low radiation exposures to family members of patients undergoing (125)I prostate implantation. It was clear that (125)I seed implantation did not pose a threat to the safety of family members.

Predictive factors for urinary toxicity after iodine-125 prostate brachytherapy with or without supplemental external beam radiotherapy

PURPOSE

We examined the factors associated with urinary toxicities because of brachytherapy with iodine-125 with or without supplemental external beam radiotherapy (EBRT) for prostate cancer.

METHODS AND MATERIALS

We investigated 1313 patients with localized prostate cancer treated with iodine-125 brachytherapy with or without supplemental EBRT between 2003 and 2009. The International Prostate Symptom Score (IPSS) and Common Terminology Criteria for Adverse Events data were prospectively determined. Patients, treatment, and implant factors were investigated for their association with urinary toxicity or symptoms.

RESULTS

IPSS resolution was not associated with biologically effective dose (BED). Baseline IPSS, total needles, and the minimal dose received by 30% of the urethra had the greatest effect according to multivariate analysis (MVA). Urinary symptom flare was associated with baseline IPSS, age, BED, and EBRT on MVA. Urinary symptom flare and urinary Grade 2 or higher (G2+) toxicity occurred in 51%, 58%, and 67% (p = 0.025) and 16%, 22%, and 20% (p = 0.497) of the <180, 180-220, and >220 Gy BED groups, respectively. Urinary G2+ toxicity was associated with baseline IPSS, neoadjuvant androgen deprivation therapy (NADT), and seed density on MVA. When we divided patients into four groups according to prostate volume (<30 cc or ≥30 cc) and NADT use, urinary G2+ toxicity was most commonly observed in those patients with larger prostates who received NADT, and least in the patients with smaller prostates and no NADT.

CONCLUSIONS

NADT was associated with urinary G2+ toxicity. Higher dose and supplemental EBRT did not appear to increase moderate to severe urinary toxicities or time to IPSS resolution; however, it influenced urinary symptom flare.

Erectile function status is highly associated with prostate-specific antigen bounce in localized prostate cancer patients treated with permanent prostate brachytherapy

OBJECTIVES

To examine the relationship between erectile function status and prostate-specific antigen bounce after prostate brachytherapy for localized prostate cancer.

METHODS

We identified 154 patients who were followed up for at least 24 months after brachytherapy. Erectile function status was assessed prospectively before brachytherapy (baseline), and 3, 6, 12, 18, 24 and 36 months postoperatively using the International Index of Erectile Function-15 questionnaire. Prostate-specific antigen bounce was defined as an increase of at least 0.4 ng/mL from a previous prostate-specific antigen level with a subsequent decline equal to, or less than, the initial nadir without treatment. A logistic regression analysis was used to identify a significant set of independent predictors of prostate-specific antigen bounce after brachytherapy.

RESULTS

Prostate-specific antigen bounce was observed in 38 (24.7%) men. The prostate-specific antigen bounce group had a higher erectile function domain score, higher orgasmic function domain score, and higher total International Index of Erectile Function-15 score before (at baseline) and after brachytherapy (3, 6, 12, 18, 24 and 36 months after brachytherapy) than their counterparts (P < 0.05). Of the 77 patients who completed the International Index of Erectile Function-15 questionnaire 18 months after brachytherapy (the median time of prostate-specific antigen bounce), sexual desire and intercourse satisfaction domain scores, and total International Index of Erectile Function scores 18 months after brachytherapy correlated with the occurrence of prostate-specific antigen bounce. A multivariate analysis identified the intercourse satisfaction domain score 18 months after brachytherapy as an independent indicator for the occurrence of prostate-specific antigen bounce (P = 0.008).

CONCLUSIONS

International Index of Erectile Function-15 score seems to be correlated with the prostate-specific antigen bounce in prostate cancer patients undergoing brachytherapy, and an occurrence of prostate-specific antigen bounce seems to be more likely in those who are more sexually active.

Three-dimensional conformal arc radiotherapy using a C-arm linear accelerator with a computed tomography on-rail system for prostate cancer: clinical outcomes

Background

We report the feasibility and treatment outcomes of image-guided three-dimensional conformal arc radiotherapy (3D-CART) using a C-arm linear accelerator with a computed tomography (CT) on-rail system for localized prostate cancer.

Methods and materials

Between 2006 and 2011, 282 consecutive patients with localized prostate cancer were treated with in-room CT-guided 3D-CART. Biochemical failure was defined as a rise of at least 2.0 ng/ml beyond the nadir prostate-specific antigen level. Toxicity was scored according to the National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.0.

Results

A total of 261 patients were analyzed retrospectively (median follow-up: 61.6 months). The median prescribed 3D-CART dose was 82 Gy (2 Gy/fraction, dose range: 78–86 Gy), and 193 of the patients additionally received hormonal therapy. The 5-year overall survival rate was 93.9 %. Among low-, intermediate-, and high-risk patients, 5-year rates of freedom from biochemical failure were 100, 91.5 and 90.3 %, respectively. Rates of grade 2–3 late gastrointestinal and genitourinary toxicities were 2.3 and 11.4 %, respectively. No patient experienced late grade 4 or higher toxicity.

Conclusions

In-room CT-guided 3D-CART was feasible and effective for localized prostate cancer. Treatment outcomes were comparable to those previously reported for intensity-modulated radiotherapy.

Comparison of genitourinary and gastrointestinal toxicity among four radiotherapy modalities for prostate cancer: Conventional radiotherapy, intensity-modulated radiotherapy, and permanent iodine-125 implantation with or without external beam radiotherapy

PURPOSE

To compare late genitourinary (GU) and gastrointestinal (GI) toxicity following different prostate cancer treatment modalities.

MATERIALS AND METHODS

This study included 1084 consecutive prostate cancer patients treated with conventional radiotherapy, intensity-modulated radiotherapy (IMRT), permanent iodine-125 implantation (PI) alone, and PI combined with external beam radiotherapy (PI+EBRT). The effects of treatment- and patient-related factors on late grade ⩾ 2 (G2+) GU/GI toxicity risk were assessed.

RESULTS

The median follow-up was 43 months (range, 12-97 months). Compared to the PI+EBRT, there was significantly less G2+ GU toxicity in the conventional radiotherapy (hazard ratio [HR] = 0.39; 95% CI, 0.20-0.77) and the IMRT (HR=0.45, 95% CI, 0.27-0.73). Compared to the PI+EBRT, there was significantly more G2+ GI toxicity in the IMRT (HR = 2.38; 95% CI, 1.16-4.87). In PI-related groups, prostate equivalent dose in 2 Gy fractions was a significant predictor of G2+ GU toxicity (p = 0.001), and the rectal volume receiving more than 100% of the prescribed dose was a significant predictor of G2+ GI toxicity (p = 0.001).

CONCLUSION

The differences in the late G2+ GU/GI risk cannot be explained by the differences in treatment modalities themselves, but by the total radiation dose to the GU/GI tract, which had a causal role in the development of late G2+ GU/GI toxicity across all treatment modality groups.

Dosimetric variations due to interfraction organ deformation in cervical cancer brachytherapy

We quantitatively estimated dosimetric variations due to interfraction organ deformation in multi-fractionated high-dose-rate brachytherapy (HDRBT) for cervical cancer using a novel surface-based non-rigid deformable registration. As the number of consecutive HDRBT fractions increased, simple addition of dose-volume histogram parameters significantly overestimated the dose, compared with distribution-based dose addition.

Combination of 5α-reductase inhibitor with combined androgen blockade (CAB) as a novel cytoreductive regimen before prostate brachytherapy: Ultra-CAB

We report a first case of using a 5α-reductase inhibitor (5ARI) and combined androgen blockade (CAB) as a cytoreductive regimen before prostate brachytherapy. Prostate volume reduction with CAB is limited to approximately 40% in most cases, making it difficult to meet anatomical constraints to perform these procedures in cases with large prostate volume. With the added administration of 5ARI, further volume reduction can be expected. Here, we describe this cytoreductive regimen used in a 63 year-old prostate cancer patient who became eligible to receive brachytherapy after dutasteride (0.5 mg daily) was added to CAB and prostate volume reduction of 57% was achieved.