Long-term oncologic outcomes of low dose-rate brachytherapy compared to hypofractionated external beam radiotherapy for intermediate -risk prostate cancer.

PURPOSE: To compare the long-term oncologic outcomes of intermediate risk (IR) prostate cancer (PCa) patients treated with low dose-rate brachytherapy (LDR-BT) or moderate hypofractionated external beam radiotherapy (HF-EBRT). METHODS AND MATERIALS: Patients diagnosed with IR PCa and treated with LDR-BT or HF-EBRT between January 2005 and December 2013 were included. Brachytherapy treatment involved a transperineal implant of iodine-125 to a dose of 145 Gy to the PTV, while HF-EBRT was delivered using intensity modulated radiotherapy with 60 Gy in 20 fractions. The Phoenix ''nadir +2'' threshold was used to define biochemical relapse (BR). The cumulative incidence function (CIF) of BR and metastases was reported for each group and compared using the Gray's test to account for the competing risk of death. The Kaplan-Meier (KM) method was used to estimate overall survival (OS) and prostate cancer specific survival (PCSS). Univariate (UVA) and multivariable (MVA) analysis of the CIF of BR and metastases were performed. A 2-tailed p-value ≤ 0.05 was considered statistically significant. RESULTS: Overall, 122 and 124 patients were treated with LDR-BT and HF-EBRT respectively. Median follow-up was 95 months [interquartile range (IQR): 79-118] in the LDR-BT group and 96 months (IQR: 63-123) in the HF-EBRT group. BR was observed in 5 patients treated with LDR-BT and 34 treated with HF-EBRT. At 60 and 90 months, the CIF of BR was 0.9% and 3.5% in the LDR-BT group vs. 16.6% and 23.7% in the HF-EBRT (p < 0.001). The CIF of metastases at 90 and 108 months, was 0% and 1.6% vs. 3.4% and 9.1% in the LDR-BT and HF-EBRT groups (p = 0.003), respectively. At the last follow-up, 3 patients treated with HF-EBRT died from their cancer [PCSS of 97.5% at 8 years and none died in the LDR-BT group (p = 0.09). On UVA and MVA risk group and treatment modality were independently associated with CIF of BR. On UVA HF-EBRT and ISUP grade group 3 were associated with metastases. CONCLUSION: LDR-BT was associated with higher biochemical and metastases control in our cohort when compared to moderately HF-EBRT. In the absence of a randomized trial, LDR-BT when feasible should be offered to patients with a life expectancy of >8 years.

Control charts for evaluation of quality of low-dose-rate brachytherapy for prostate cancer.

Purpose: Variations in dosimetric outcomes among patients treated with low-dose-rate brachytherapy for prostate cancer exist, even when implants are within dose constraints. Here, we used control charts to investigate reasons for intra-patient dosimetric variability. Material and methods: Univariate and multivariate control charts for prostate V100 (percentage of prostate volume that received 100% of prescribed radiation dose), D90 (radiation dose to 90% of prostate volume), and RV100 (rectal wall volume that received 100% of prescribed radiation dose) were generated for 212 consecutive prostate cancer patients implanted with iodine-125 (125I) radioactive seeds at the Princess Margaret Cancer Centre. Control limits were calculated based on the first fifty implants. Data points that were out of control were identified, and their pre-treatment and post-treatment dosimetric and clinical parameters were compared to data points that were in-control, using Student's t-test. Results: All implants were clinically acceptable. Twelve data points exceeded multivariate control limits. Ten of those points fell below the lower control limit of V100 control chart. Average prostate edema in the 10 out-of-control patients on both multivariate and V100 charts was 8.3%, as compared to 0.4% for in-control patients (p < 0.04). Two patients were observed to be out-of-control on multivariate control chart, but not on V100 control chart, and were found to have a reduction in prostate volume of 19.1% and 20.1% at one month after seed implant, compared to prostate volumes of pre-implantation evaluations. Conclusions: Control charts helped in identifying cases with out-of-control variability in post-plan prostate dosimetry. Post-treatment prostatic edema and contraction are important factors predicting variability in patients treated with 125I permanent seed brachytherapy.

Implementation of deep learning-based auto-segmentation for radiotherapy planning structures: a workflow study at two cancer centers.

PURPOSE: We recently described the validation of deep learning-based auto-segmented contour (DC) models for organs at risk (OAR) and clinical target volumes (CTV). In this study, we evaluate the performance of implemented DC models in the clinical radiotherapy (RT) planning workflow and report on user experience. METHODS AND MATERIALS: DC models were implemented at two cancer centers and used to generate OAR and CTVs for all patients undergoing RT for a central nervous system (CNS), head and neck (H&N), or prostate cancer. Radiation Therapists/Dosimetrists and Radiation Oncologists completed post-contouring surveys rating the degree of edits required for DCs (1 = minimal, 5 = significant) and overall DC satisfaction (1 = poor, 5 = high). Unedited DCs were compared to the edited treatment approved contours using Dice similarity coefficient (DSC) and 95% Hausdorff distance (HD). RESULTS: Between September 19, 2019 and March 6, 2020, DCs were generated on approximately 551 eligible cases. 203 surveys were collected on 27 CNS, 54 H&N, and 93 prostate RT plans, resulting in an overall survey compliance rate of 32%. The majority of OAR DCs required minimal edits subjectively (mean editing score ≤ 2) and objectively (mean DSC and 95% HD was ≥ 0.90 and ≤ 2.0 mm). Mean OAR satisfaction score was 4.1 for CNS, 4.4 for H&N, and 4.6 for prostate structures. Overall CTV satisfaction score (n = 25), which encompassed the prostate, seminal vesicles, and neck lymph node volumes, was 4.1. CONCLUSIONS: Previously validated OAR DC models for CNS, H&N, and prostate RT planning required minimal subjective and objective edits and resulted in a positive user experience, although low survey compliance was a concern. CTV DC model evaluation was even more limited, but high user satisfaction suggests that they may have served as appropriate starting points for patient specific edits.

Evaluation of the dosimetric impact of loss and displacement of seeds in prostate low-dose-rate brachytherapy.

PURPOSE: To analyze the seed loss and displacement and their dosimetric impact in prostate low-dose-rate (LDR) brachytherapy while utilizing the combination of loose and stranded seeds. MATERIAL AND METHODS: Two hundred and seventeen prostate cancer patients have been treated with LDR brachytherapy. Loose seeds were implanted in the prostate center and stranded seeds in the periphery of the gland. Patients were imaged with transrectal ultrasound before implant and with computerized tomography/magnetic resonance imaging (CT/MR) one month after implant. The seed loss and displacement had been analyzed. Their impact on prostate dosimetry had been examined. The seed distribution beyond the prostate inferior boundary had been studied. RESULTS: The mean number of seeds per patient that were lost to lung, pelvis/abdomen, urine, or unknown destinations was 0.21, 0.13, 0.03, and 0.29, respectively. Overall, 40.1% of patients had seed loss. Seed migration to lung and pelvis/abdomen occurred in 15.5% and 10.5% of the patients, respectively. Documented seed loss to urine was found in 3% of the patients while 20% of patients had seed loss to unknown destinations. Prostate length difference between pre-plan and post-implant images was within 6 mm in more than 98% of cases. The difference in number of seeds inferior to prostate between pre-plan and post-implant dosimetry was within 7 seeds for 93% of patients. At time of implant, 98% of seeds, inferior to prostate, were within 5 mm and 100% within 15 mm, and in one month post-implant 83% within 9 mm and 96.3% within 15 mm. Prostate post-implant V100, D90, and rectal wall RV100 for patients without seed loss were 94.6%, 113.9%, and 0.98 cm(3), respectively, as compared to 95.0%, 114.8%, and 0.95 cm(3) for the group with seed loss. CONCLUSIONS: Seed loss and displacement have been observed to be frequent. No correlation between seed loss and displacement and post-plan dosimetry has been reported.

Dosimetric evaluation of clinical target volume in the postimplant analysis of low-dose-rate brachytherapy for prostate cancer.

PURPOSE: Brachytherapy is an effective single treatment modality for low- and intermediate-risk prostate cancer. In this study, we defined a clinical target volume (CTV) and evaluated its dosimetry 1 month after the low-dose-rate brachytherapy procedure. METHODS AND MATERIALS: One hundred ninety-eight consecutive patients treated for prostate cancer by iodine-125 seed brachytherapy were assessed. Prostate dosimetry was stratified according to British Columbia Cancer Agency criteria, with good implants having both V100 (percentage of target volume that receives 100% of the prescribed dose) > 85% and D90 (percentage of the prescribed dose received by 90% of the target volume) > 90%, suboptimal implants with V100 of 75-85%, or D90 80-90%, whereas poor implants were defined as those with V100 < 75 or D90 < 80%. CTV dosimetry stratification was performed according to the same dose coverage criteria, albeit to the CTV. RESULTS: One hundred ninety-two patients (97%) had good prostate radiation coverage, whereas only 165 patients (83%) had good postimplant CTV dosimetry. Patients with suboptimal vs. good CTV dosimetry had prostate edema of 7.8 ± 0.2% vs. 0.2 ± 0.1%, respectively (p = 0.001). CONCLUSIONS: Prostate seed implants with optimal dosimetry to prostate may still have suboptimal D90 and V100 for the CTV, especially in the presence of postimplant edema. A consensus is needed for definition and evaluation of CTV in postimplant setting for low-dose-rate prostate brachytherapy.

Incidental prophylactic nodal irradiation and patterns of nodal relapse in inoperable early stage NSCLC patients treated with SBRT: a case-matched analysis.

PURPOSE: Reported rates of non-small cell lung cancer (NSCLC) nodal failure following stereotactic body radiation therapy (SBRT) are lower than those reported in the surgical series when matched for stage. We hypothesized that this effect was due to incidental prophylactic nodal irradiation. METHODS AND MATERIALS: A prospectively collected group of medically inoperable early stage NSCLC patients from 2004 to 2010 was used to identify cases with nodal relapses. Controls were matched to cases, 2:1, controlling for tumor volume (ie, same or greater) and tumor location (ie, same lobe). Reference (normalized to equivalent dose for 2-Gy fractions [EQD2]) point doses at the ipsilateral hilum and carina, demographic data, and clinical outcomes were extracted from the medical records. Univariate conditional logistical regression analyses were performed with variables of interest. RESULTS: Cases and controls were well matched except for size. The controls, as expected, had larger gross tumor volumes (P=.02). The mean ipsilateral hilar doses were 9.6 Gy and 22.4 Gy for cases and controls, respectively (P=.014). The mean carinal doses were 7.0 Gy and 9.2 Gy, respectively (P=.13). Mediastinal nodal relapses, with and without ipsilateral hilar relapse, were associated with mean ipsilateral hilar doses of 3.6 Gy and 19.8 Gy, respectively (P=.01). The conditional density plot appears to demonstrate an inverse dose-effect relationship between ipsilateral hilar normalized total dose and risk of ipsilateral hilar relapse. CONCLUSIONS: Incidental hilar dose greater than 20 Gy is significantly associated with fewer ipsilateral hilar relapses in inoperable early stage NSCLC patients treated with SBRT.

Sector analysis of dosimetry of prostate cancer patients treated with low-dose-rate brachytherapy.

PURPOSE: Brachytherapy is an effective single treatment modality for low- and intermediate-risk prostate cancer. Here, we compare the radiation doses in different prostate sectors between the preimplant planning images and the postimplant dosimetry. METHODS AND MATERIALS: Two hundred fifteen consecutive patients treated for prostate cancer by (125)I seed brachytherapy were assessed. Pretreatment plans using transrectal ultrasound images of the prostate were compared with the dose calculated on posttreatment MRI and CT scans obtained 1 month after seed implantation. Twelve sectors were generated by dividing the prostate base, midgland, and apex into four quadrants each. Pretreatment and posttreatment dosimetry were compared between the 12 different sectors of the prostate. RESULTS: Average V100 (percentage of prostate volume that receives 100% of the prescribed dose) in the preimplant planning images of the prostate was 99.9 ± 0.25% compared with postimplant V100 of 94.8 ± 3.77% (p < 0.0001). Prostate V100 in the postimplant dosimetry was >91% in all sectors, except the anterior base sector, in which it was 64.87 ± 20.96%. Average 1-month D90 (the dose to 90% of the prostate volume) was 114.5 ± 10.55%. D90 at 1 month compared with preimplant planning was lower in the prostate base and higher in the prostate apex (p < 0.001). CONCLUSIONS: Our results show that in (125)I seed brachytherapy, prostate base receives a lower dose and apex receives a higher dose compared with preimplant planned dose coverage.

An evaluation of the Clarity 3D ultrasound system for prostate localization.

The purpose of this study is to evaluate the accuracy and precision of the Clarity 3D ultrasound system to track prostate gland positional variations due to setup error and organ motion. Seventeen patients (n = 17) undergoing radical external beam radiation therapy for localized prostate cancer were studied. Subsequent to initial reference ultrasound and planning CT scans, each patient underwent seven repeat weekly tracking CT and ultrasound (US) scans during the course of treatment. Variations in the location of the prostate between reference and tracking scans were measured. Differences reported by CT and ultrasound scans are compared. Ultrasound tracking was initially performed clinically by a group of trained general users. Retrospective prostate localization was then performed by a trained dedicated user upon the original raw data set and also a reduced data set derived from the original by an expert user from Resonant Medical. Correlation accuracy between ultrasound and CT shifts acquired and delineated by a pool of trained general users was deemed unacceptable for radiotherapy purposes. A mean discrepancy between CT and US localizations of greater than 10 mm, with a 5 mm or greater discrepancy rate of nearly 90%, was observed. Retrospective analysis by a dedicated user of both the original and Resonant Medical reduced data sets yielded mean CT-Us discrepancies of 8.7 mm and 7.4 mm, respectively. Unfortunately, the 5 mm or greater CT-US discord rate for these retrospective analyses failed to drop below 80%. The greatest disparity between CT and ultrasound was consistently observed in the superior-inferior direction, while greatest agreement was achieved in the lateral dimension. Despite an expert reanalysis of the original data, the Clarity ultrasound system failed to deliver an acceptable level of geometric accuracy required for modern radiotherapy purposes.

External validation of the pretreatment nomogram to predict acute urinary retention after (125)I prostate brachytherapy.

PURPOSE: Acute urinary retention (AUR) after (125)I prostate brachytherapy has a negative impact on quality of life. Recently, the authors developed a nomogram to predict the risk of AUR preoperatively. The aim of this study was to assess the external validity of the nomogram. METHODS AND MATERIALS: The nomogram was initially developed on 714 patients treated with (125)I prostate brachytherapy at the University Medical Center Utrecht, the Netherlands. Predictive factors included in the nomogram were prostate volume, international prostate symptom score, neoadjuvant hormonal treatment, and prostate protrusion. For external validation, the data of 715 consecutive patients treated between January 2003 and July 2008 at the Princess Margaret Hospital, Toronto, were used. The performance of the nomogram was evaluated by discrimination (ability to distinguish between patients who develop AUR yes or no) and calibration (agreement between observed and predicted numbers of AUR). RESULTS: Of the 715 patients treated at the Princess Margaret Hospital, 67 patients (9.4%) developed AUR compared with 8.0% in the University Medical Center Utrecht cohort. In the validation data set, the discriminatory ability of the nomogram was good (receive operating characteristic area: 0.86; 95% confidence interval: 0.82-0.91), and comparable to the derivation data set (receive operating characteristic area: 0.82; 95% confidence interval: 0.77-0.88). Comparison between the predicted risks and the observed frequencies of AUR showed underestimation of the nomogram in the validation data set for high AUR risks values. Still, the negative predictive value for the risk of AUR, using a cutoff value of 5%, was high (98.1%). CONCLUSION: External validation of the nomogram shows adequate discrimination of patients with and without AUR. Therefore, the nomogram can aid in individualized treatment decision making.

The efficacy of hyperbaric oxygen therapy in the treatment of medically refractory soft tissue necrosis after penile brachytherapy.

PURPOSE: Soft tissue necrosis is reported in up to 26% of patients undergoing radiotherapy for penile cancer. Management options include local irrigation, wound debridement, antibiotics, anti-inflammatory medication, and analgesics. Refractory lesions may be treated with partial penectomy. Hyperbaric oxygen therapy (HBO) has a well-defined role in the treatment of late radiation toxicities. We present experience with HBO for medically refractory soft tissue necrosis after penile brachytherapy. METHODS AND MATERIALS: From November 2001 to January 2009, 7 men of 43 treated with penile brachytherapy for squamous carcinoma developed refractory soft tissue necrosis and were treated with HBO. All had received a prescribed dose of 60 Gy through interstitial brachytherapy using Paris system guidelines. All had failed conservative medical therapies for soft tissue necrosis. RESULTS: Median age was 55 years (range, 35-72 years). Comorbidities potentially effecting wound healing included hypertension (2), current smokers (5), former smoker (1) but no diabetes mellitus, or peripheral vascular disease. Median time between completion of brachytherapy and appearance of soft tissue necrosis was 13 months (range, 9-24 months) and the median interval before starting HBO was 7.5 months (range, 3-13 months). The median number of "dives" per HBO course was 40 (30-53). All 7 experienced an excellent response with healing of the necrosis and resolution of symptoms, although 3 required an additional course, 2 for consolidation of healing, and 1 for a relapse 4 months later. No patient was submitted to penectomy. CONCLUSIONS: HBO should be considered as a treatment option in patients with refractory soft tissue necrosis of the penis after brachytherapy.

Pretreatment nomogram to predict the risk of acute urinary retention after I-125 prostate brachytherapy.

PURPOSE: Acute urinary retention (AUR) after iodine-125 (I-125) prostate brachytherapy negatively influences long-term quality of life and therefore should be prevented. We aimed to develop a nomogram to preoperatively predict the risk of AUR. METHODS: Using the preoperative data of 714 consecutive patients who underwent I-125 prostate brachytherapy between 2005 and 2008 at our department, we modeled the probability of AUR. Multivariate logistic regression analysis was used to assess the predictive ability of a set of pretreatment predictors and the additional value of a new risk factor (the extent of prostate protrusion into the bladder). The performance of the final model was assessed with calibration and discrimination measures. RESULTS: Of the 714 patients, 57 patients (8.0%) developed AUR after implantation. Multivariate analysis showed that the combination of prostate volume, IPSS score, neoadjuvant hormonal treatment and the extent of prostate protrusion contribute to the prediction of AUR. The discriminative value (receiver operator characteristic area, ROC) of the basic model (including prostate volume, International Prostate Symptom Score, and neoadjuvant hormonal treatment) to predict the development of AUR was 0.70. The addition of prostate protrusion significantly increased the discriminative power of the model (ROC 0.82). Calibration of this final model was good. The nomogram showed that among patients with a low sum score (<18 points), the risk of AUR was only 0%-5%. However, in patients with a high sum score (>35 points), the risk of AUR was more than 20%. CONCLUSION: This nomogram is a useful tool for physicians to predict the risk of AUR after I-125 prostate brachytherapy. The nomogram can aid in individualized treatment decision-making and patient counseling.

The effect of obesity on rectal dosimetry after permanent prostate brachytherapy.

OBJECTIVES: Men with higher body mass index (BMI) tend to have more fatty tissue in prostate-rectum interface, which may reduce the rectal wall dose by the inverse square law. We hypothesized that men with higher BMI will have a lower dose to the rectal wall and less rectal toxicity after permanent prostate implant. METHODS: Prospectively collected data on rectal dosimetry/toxicity and BMI of 407 patients who underwent iodine-125 ((125)I) prostate implant were analyzed. Postimplant dosimetry used CT-MRI fusion on Day 30. Rectal wall was contoured on all slices where seeds were seen. The volume of rectal wall receiving the prescribed dose (RV(100) in cm(3)) and the dose to 1cc of rectal wall (RD(1cc)) were reported. Other factors evaluated for association with rectal dosimetry and toxicity included age, diabetes, hypertension, smoking, use of neoadjuvant hormones, T stage, baseline prostate volume, 1 month prostate edema, seed type and activity, and prostate dosimetry factors (the isodose enclosing 90% of the prostate volume [D(90)], the percentage of the prostate volume enclosed by the prescription [V(100)], and the percentage of the prostate volume enclosed by the 150% isodose [V(150)]). Rectal toxicity was reported as per Radiation Therapy Oncology Group criteria. RESULTS: BMIs ranged from 15.9 to 46.8 (mean+/-standard deviation [SD]: 27.8+/-4.2). The mean+/-SD values for RV(100) and RD(1cc) were 0.79+/-0.49cm(3) and 128.2+/-27.8Gy, respectively. There was a significant negative association of BMI with RV(100) (p=0.007) and RD(1cc) (p=0.01) on univariate analysis. The mean RV(100) and RD(1cc) for men with higher BMI (>27.8) were lower compared with their slimmer counterparts (0.70 vs. 0.86cm(3) and 123.4 vs. 132.4Gy, respectively). On multivariate analysis for RV(100) and RD(1cc), BMI remained significant (p-values 0.004 and 0.01, respectively) along with prostate volume and V(150), suggesting that anatomic factors are important in rectal dosimetry in prostate brachytherapy. Overall the incidence of Radiation Therapy Oncology Group acute rectal toxicity was 12% (Grade 2, 1.3%) and chronic 6% (Grade 2, 0.5%). No Grade 3 toxicity occurred. None of the factors evaluated were predictive for rectal toxicity. CONCLUSION: Men with a lower BMI received a higher rectal wall dose compared with those with higher BMI. This did not, however, translate into greater rectal toxicity.

Sequential comparison of seed loss and prostate dosimetry of stranded seeds with loose seeds in 125I permanent implant for low-risk prostate cancer.

PURPOSE: To compare stranded seeds (SSs) with loose seeds (LSs) in terms of prostate edema, dosimetry, and seed loss after (125)I brachytherapy. METHODS AND MATERIALS: Two prospective cohorts of 20 men participated in an institutional review board-approved protocols to study postimplant prostate edema and its effect on dosimetry. The LS cohort underwent brachytherapy between September 2002 and July 2003 and the SS cohort between April 2006 and January 2007. Both cohorts were evaluated sequentially using computed tomography-magnetic resonance imaging fusion-based dosimetry on Days 0, 7, and 30. No hormonal therapy or supplemental beam radiotherapy was used. RESULTS: Prostate edema was less in the SS cohort at all points (p = NS). On Day 0, all the prostate dosimetric factors were greater in the LS group than in the SS group (p = 0.003). However, by Days 7 and 30, the dosimetry was similar between the two cohorts. No seeds migrated to the lung in the SS cohort compared with a total of five seeds in 4 patients in the LS cohort. However, the overall seed loss was greater in the SS cohort (24 seeds in 6 patients; 1.1% of total vs. 0.6% for LSs), with most seeds lost through urine (22 seeds in 5 patients). CONCLUSION: Despite elimination of venous seed migration, greater seed loss was observed with SSs compared with LSs, with the primary site of loss being the urinary tract. Modification of the technique might be necessary to minimize this. Prostate dosimetry on Days 7 and 30 was similar between the SS and LS cohorts.

Neonatal circumcision and invasive squamous cell carcinoma of the penis: a report of 3 cases and a review of the literature.

Neonatal circumcision is widely considered to have a protective effect against the development of squamous cell carcinoma of the penis in later life. We report 3 cases of squamous cell carcinoma in men who were circumcised as neonates. The 3 men, aged 49, 55 and 64 years, presented for consideration of brachytherapy. The tumour stage was T3 in 1 case and T1 in the others. The tumours were moderately differentiated in 2 cases and well differentiated in 1 case. All 3 men had a remote history of penile condylomata acuminatum 20-30 years earlier. Oncogenic human papillomavirus (HPV) was found in the tumour specimen in 1 case. All 3 were treated with brachytherapy to the primary tumour on the glans. In 2 cases, subsequent staging inguinal node dissection was indicated because of the grade and stage of the primary tumour. A history of remote HPV infection should increase the index of suspicion for any nonhealing penile lesion, despite a history of neonatal circumcision.

Loose seeds vs. stranded seeds: a comparison of critical organ dosimetry and acute toxicity in (125)I permanent implant for low-risk prostate cancer.

PURPOSE: To compare the critical organ dosimetry and toxicity of loose seeds (LS) with stranded seeds (SS) in (125)I permanent implant for low-risk prostate cancer. METHODS AND MATERIALS: Two cohorts of 20 patients each were treated in Institutional Review Board-approved protocols designed to assess prostate edema and seed stability using MR-CT fusion on Days 0, 7, and 30 after permanent implant. (125)I LS were used for one cohort and (125)I SS for the other. Rectal wall dosimetry was compared for the two cohorts using RV100 and RD1cc and urethral dosimetry using UD5, UD30, and UV150. Statistical comparisons were performed using unpaired Student's t test. RESULTS: At each time point (Days 0, 7, and 30), both the mean RD1 cc (SS: 123.1, 139.7, and 156.1 Gy vs. LS: 90.2, 104, and 129.4 Gy, respectively) and the mean RV100 (SS: 0.63, 1.0, and 1.4 cc vs. LS: 0.2, 0.4, and 0.73 cc, respectively) were significantly higher for strands (all p-values<0.01). Only 1 patient developed radiotherapy oncology group (RTOG) Grade 1 acute rectal toxicity in the loose seed cohort, whereas 3 patients had Grade 1 and 1 patient had Grade 2 toxicity with strands. The mean percentage increase of UD5 (7.7% LS vs. 24.6% SS; p=0.004) and UD30 (5% LS vs. 15.9% SS; p=0.02) from preplan to Day 30 was higher for strands. The increase in UV150 from baseline to Day 30 was significantly higher for strands (0.2 vs. 0.06 cc; p=0.01). Urinary toxicity was similar in both cohorts. CONCLUSIONS: SS resulted in higher dose to urethra and rectal wall compared with LS on postimplant dosimetry. A trend toward higher acute rectal toxicity rate was observed for SS.

Skin-sparing radiation using intensity-modulated radiotherapy after conservative surgery in early-stage breast cancer: a planning study.

PURPOSE: To evaluate the feasibility of skin-sparing by configuring it as an organ-at-risk (OAR) while delivering whole-breast intensity-modulated radiotherapy (IMRT) in early breast cancer. METHODS AND MATERIALS: Archival computed tomography scan images of 14 left-sided early-breast tumor patients who had undergone lumpectomy were selected for this study. Skin was contoured as a 4- to 5-mm strip extending from the patient outline to anterior margin of the breast planning target volume (PTV). Two IMRT plans were generated by the helical tomotherapy approach to deliver 50 Gy in 25 fractions to the breast alone: one with skin dose constraints (skin-sparing plan) and the other without (non-skin-sparing plan). Comparison of the plans was done using a two-sided paired Student t test. RESULTS: The mean skin dose and volume of skin receiving 50 Gy were significantly less with the skin-sparing plan compared with non-skin-sparing plan (42.3 Gy vs. 47.7 Gy and 12.2% vs. 57.8% respectively; p < 0.001). The reduction in skin dose was confirmed by TLD measurements in anthropomorphic phantom using the same plans. Dose-volume analyses for other OARs were similar in both plans. CONCLUSIONS: By configuring the skin as an OAR, it is possible to achieve skin dose reduction while delivering whole-breast IMRT without compromising dose profiles to PTV and OARs.

Sparing the parotid glands and surgically transferred submandibular gland with helical tomotherapy in post-operative radiation of head and neck cancer: a planning study.

BACKGROUND AND PURPOSE: To evaluate the feasibility of sparing the parotid glands and surgically transferred submandibular gland (SMG) by intensity modulated radiotherapy (IMRT) in post-operative cases of head and neck cancer (HNC). MATERIALS AND METHODS: Ten patients (larynx-2, base of tongue-4, tonsil-3, and unknown primary-1; pathologic stages III-IV) who underwent SMG transfers on the side of N0 neck along with definitive surgery were selected for this study. IMRT planning was done retrospectively using helical tomotherapy approach. Planning objective was to deliver 60 Gy to PTV1 and 54 Gy to PTV2 while maintaining the mean dose to the total parotid volume (TPV) and SMG less than 26 Gy. RESULTS: The mean dose (+/-SD) to the TPV and SMG were 25+/-0.6 Gy and 23+/-1.9 Gy, respectively. The D(95) for PTV1 and PTV2 were 59.9+/-0.1 Gy and 54.9+/-0.3 Gy, respectively, satisfying our planning goal for PTV coverage. The D(99) for PTV1 and PTV2 were 58.2+/-0.7 Gy and 49.5+/-2.2 Gy, respectively, showing that sparing the salivary glands did not result in underdosing of the PTVs. CONCLUSIONS: By combining the gland transfer and IMRT, the mean dose to TPV and transferred SMG could be reduced to less than 26 Gy in post-operative patients of HNC.

Prognostic value of response to external radiation in stage IIIB cancer cervix in predicting clinical outcomes: a retrospective analysis of 556 patients from India.

BACKGROUND AND PURPOSE: To evaluate the prognostic significance of response to external beam radiation (EBRT) in predicting the clinical outcomes in stage IIIB cancer cervix and to find out factors affecting response to EBRT. PATIENTS AND METHODS: This retrospective study included 556 patients of cancer cervix stage IIIB treated between 1996 and 2001 with EBRT (46Gy/23fx/4.5 weeks) followed by intracavitary radiotherapy (ICRT). At the end of EBRT, response to EBRT was grouped as 'no gross residual tumor'(NRT) or 'gross residual tumor'(GRT). RESULTS: Follow up ranged from 2 to 93 months with a median of 36 months. Median dose to point A was 81Gy. At the end of EBRT, 393 patients (70.7%) attained NRT response. NRT responders had significantly better 5 year pelvic control, disease free survival (DFS) and overall survival (OS) than those who had a GRT response (75.6 vs. 54.6%; 60.6 vs. 31.9% and 62.6 vs. 33.7%, respectively; all P values <0.0001). Apart from response to EBRT, overall treatment time also has emerged as an independent factor to affect all clinical outcomes in multivariate analysis but age had significant impact on pelvic control only. Age was the only factor, which significantly influenced the response to EBRT in univariate as well as multivariate analysis (P=<0.001, OR=1.973, 95% C.I. 1.357-2.868). Patients with age more than 50 years had more NRT response (77%) than patients with age less than 50 years (63.8%). CONCLUSIONS: Patients who attain NRT response to EBRT will have an impressive long term pelvic control, DFS and OS in stage IIIB cancer cervix. Older patients (>or=50 years) attain significantly higher NRT rates than younger patients.

Results of salvage radiotherapy after inadequate surgery in invasive cervical carcinoma patients: a retrospective analysis.

PURPOSE: To evaluate the results of salvage radiotherapy (RT) after inadequate surgery in patients with invasive carcinoma of the cervix. METHODS AND MATERIALS: Between 1996 and 2001, 105 invasive cervical carcinoma patients were treated at our center with external beam RT with or without intracavitary RT after having undergone total/subtotal hysterectomy at outside institutions. RESULTS: The median follow-up was 34 months. The gap between surgery and RT was 23-198 days (median, 80). Clinically visible residual disease was present in 81 patients (77.1%). Total hysterectomy had been done in 82 patients (78%) and subtotal hysterectomy in 23 patients (22%). The 5-year overall survival, disease-free survival, and pelvic control rates of all patients were 55.2%, 53.3%, and 72.4%, respectively. On univariate analysis, older age, total hysterectomy, hemoglobin level >10 g% before RT, nonsquamous histologic type, use of intracavitary RT, a shorter gap between surgery and RT, and the absence of, or a small volume of, residual disease favorably affected the outcome. The 5-year actuarial rate of late toxicity (Radiation Therapy Oncology Group Criteria) was 19% in the rectum, 4.8% in the bladder, 24.8% in the skin, and 14.3% in the small intestine. CONCLUSIONS: Inadequate and inappropriate surgery in invasive cervical cancer with resulting gross residual disease is common in India. Factors such as the use of intracavitary RT, the correction of anemia, and a shorter gap between surgery and RT will enable postoperative RT to achieve acceptable results with minimal morbidity.