Anuj V. Peddada

High-dose-rate brachytherapy for large prostate volumes (≥50 cc)—Uncompromised dosimetric coverage and acceptable toxicity

PURPOSE The purpose of this study was to review our single-institution experience using high-dose-rate (HDR) brachytherapy in patients with large-volume prostate glands (> or =50cc). METHODS AND MATERIALS Fifty-four patients treated with HDR brachytherapy for prostate cancer at the Penrose Cancer Center between 2001 and 2006 were identified as having an ultrasound volume of at least 50cc at the time of implant (range, 50-97.3cc; mean, 61.5cc; median, 57cc; upper quartile, 83.3-97.3cc). Neoadjuvant hormones (17 patients) were not routinely recommended unless the initial ultrasound volume suggested pubic arch interference or the patients Gleason score or prostate specific antigen prompted use. All patients received HDR brachytherapy as a boost before or after conformal external beam radiation therapy to 4500cGy. Boost brachytherapy doses ranged from 1600 to 1900cGy, given in two to three fractions. RESULTS The median D(90) (minimal dose to 90% of the prostate) was 109% of prescription dose (range, 95-115%) and the median V(100) (volume receiving 100% of the dose) was 96% (range, 90-99%). V(150) ranged from 10% to 35%, with a median value of 18.3%. Six patients (11%) required temporary placement of a urinary catheter for acute obstructive symptoms after brachytherapy. With a median followup of 1.8 years, there has been a single case of Grade 2 gastrointestinal toxicity and 1 patient has developed a bulbo-urethral stricture requiring dilation. There have been no cases of rectal bleeding. CONCLUSIONS Large prostate volume is not a contraindication to HDR brachytherapy. Excellent dosimetric coverage can be attained with acceptable acute toxicity.

Factors associated with radiation-induced nausea and vomiting in head and neck cancer patients treated with intensity modulated radiation therapy

BACKGROUND AND PURPOSE To investigate factors associated with radiation-induced nausea and vomiting (RINV) in the setting of head and neck intensity modulated radiation therapy (IMRT). MATERIALS AND METHODS Forty-three patients treated with IMRT for head and neck cancer between 2002 and 2007 comprise the cohort. The majority (79%) were treated with an accelerated altered fractionation scheme, and concurrent chemotherapy was delivered to 23. A retrospective review of factors associated with nausea was performed. RESULTS Eighteen patients (42%) reported grade 1 acute nausea, and seven patients (16%) reported grade 2 nausea. Factors significant for grade 1-2 nausea on univariate analysis included dose to the dorsal vagal complex of the mid-medulla, younger age, use of a low neck field, and Amifostine use. Only young age retained significance on multivariate analysis. High-grade nausea was associated with use of Amifostine (p=0.003) and concurrent chemotherapy (p=0.015). CONCLUSIONS In addition to previously recognized emetic factors, young age and radiation dose to the dorsal vagal complex of the brainstem may play a role in development of nausea during head and neck IMRT.

Dorsal Vagal Complex of the Brainstem: Conformal Avoidance to Reduce Nausea

PURPOSE To investigate the role of dose to the dorsal vagal complex (DVC) as an emetic stimulus in head-and-neck cancer patients treated with intensity modulated radiation therapy but without chemotherapy. METHODS AND MATERIALS Seventy consecutively treated patients were analyzed for factors associated with nausea. The DVC was contoured on treatment planning scans using a previously published template and mean dose to the structure was analyzed for dose response. RESULTS Nausea occurred in 26 of 70 patients (37%). Two patients (3%) experienced grade 2 nausea, with the remainder having grade 1 nausea. On univariate analysis, dose to the DVC, age, and T-stage were the only significant predictors of nausea. The highest quartile of dose to the DVC (>3000 cGy) was associated with an incidence of nausea of 67% compared with less than 30% in each of the other 3 quartiles (P = .0255). CONCLUSIONS Dose to the DVC of the brainstem appears to correlate with radiation-induced nausea and vomiting. Attentive treatment planning efforts can reduce dose to this critical structure and hopefully minimize the risk of nausea.

Clinical outcomes of image guided radiation therapy (IGRT) with gold fiducial vaginal cuff markers for high-risk endometrial cancer

Abstract Objective. To report two year clinical outcomes of image guided radiation therapy (IGRT) to the vaginal cuff and pelvic lymph nodes in a series of high-risk endometrial cancer patients. Methods. Twenty-six consecutive high-risk endometrial cancer patients requiring adjuvant radiation to the vaginal cuff and regional lymph nodes were treated with vaginal cuff fiducial-based IGRT. Seventeen (65%) received sequential chemotherapy, most commonly with a sandwich technique. Brachytherapy followed external radiation in 11 patients to a median dose of 18 Gy in 3 fractions. The median external beam dose delivered was 47.5 Gy in 25 fractions. Results. All 656 fractions were successfully imaged and treated. The median overall translational shift required for correction was 9.1 mm (standard deviation, 5.2 mm) relative to clinical set-up with skin tattoos. Shifts of 1 cm, 1.5 cm, and 2 cm or greater were performed in 43%, 14%, and 4% of patients, respectively. Acute grade 2 gastrointestinal (GI) toxicity occurred in eight patients (30%) and grade 3 toxicity occurred in one. At two years, there have been no local or regional failures and actuarial overall survival is 95%. Conclusion. Daily image guidance for high-risk endometrial cancer results in a low incidence of acute GI/genitourinary (GU) toxicity with uncompromised tumor control at two years. Vaginal cuff translations can be substantial and may possibly result in underdosing if not properly considered.

Accelerated fractionation head and neck intensity-modulated radiation therapy and concurrent chemotherapy in the community setting: Safety and efficacy considerations

This article reviews our community cancer centers experience treating head and neck cancer primarily with accelerated fractionation intensity‐modulated radiation therapy (IMRT), with or without concurrent chemotherapy, focusing on acute toxicity and efficacy.

Prevention of needle displacement in multifraction high-dose-rate prostate brachytherapy: A prospective volumetric analysis and technical considerations

PURPOSE We conducted a prospective study to evaluate needle displacements between prostate high-dose-rate (HDR) brachytherapy fractions and offer technical recommendations to help prevent displacements from the outset. METHODS AND MATERIALS Planning computed tomography and verification computed tomography scans were obtained at 1-mm slice thickness and prospectively assessed for interfraction needle movement for each fraction of a 2-fraction HDR prostate boost. For both the planning and verification CTs, distances from each needle tip to the centroid of 3 implanted prostate gold seeds were measured. We determined the mean and range of the displacement distances. RESULTS Thirty-three consecutive patients (66 fractions, 540 needle-pair positions for a total of 1080 needles) were evaluated for changes in the length between the needle tip and centroid displacement. Overall, only 0.2% of the needles had any change greater than 3.5 mm between the needle tip and centroid. The mean amount of displacement was 0.97 mm, with a standard deviation of 0.76 mm. Among the patients, no fraction had more than 1 needle with a variation greater than 3.0 mm. CONCLUSIONS Needle displacements in HDR prostate brachytherapy have been reported by numerous institutions using various techniques. We report the first study to demonstrate needle displacement of less than 1 mm on average, and we describe our process of care surrounding the implantation.

CyberKnife radiosurgery for trigeminal neuralgia: unanticipated iatrogenic effect following successful treatment

This case report of 74-year-old man with trigeminal neuralgia is presented to underscore the importance of evaluating the entire treatment plan, especially when delivering large doses where even a low percentage of the prescription dose can contribute a substantial dose to an unintended target. The patient was treated using the CyberKnife stereotactic radiosurgery system utilizing a nonisocentric beam treatment plan with a 5-mm fixed collimator generating 111 beams to deliver 6000 cGy to the 79% isodose line with a maximum dose of 7594 cGy to the target. Two weeks after treatment the patients trigeminal neuralgia symptoms resolved; however, the patient developed oral mucositis due to the treatment. This case report reviews the cause of mucositis and makes recommendations on how to prevent unintended targets from receiving treatment.