Eric L. Gressen

Thoracic reirradiation for symptomatic relief after prior radiotherapeutic management for lung cancer.

Limited information is available in the medical literature on thoracic reirradiation for patients with recurrent/persistent lung carcinoma or new primary lung tumors. Controversy exists regarding the retreatment because of concerns regarding the risk of radiation toxicity. The medical and radiotherapeutic records of more than 1,500 patients with lung cancer seen in the Department of Radiation Oncology at Thomas Jefferson University Hospital from 1982 through 1997 were searched. Twenty-three patients with history of previous thoracic radiation therapy underwent thoracic reirradiation for either biopsy-proven and/or radiographically evident tumor recurrence, metastasis, or second lung primary. Most patients were reirradiated because of progressive dyspnea, cough, thoracic pain, or hemoptysis. Each of these symptoms was evaluated separately with regard to the subjective response to reirradiation. The median follow-up time from completion of reirradiation to last correspondence with the patient and/or family was 3.2 months, with a range of 0 to 17.5 months. In six patients with hemoptysis, a decrease or resolution of this symptom was noted. Of five patients with thoracic pain attributed to carcinoma, four noted an improvement in pain after reirradiation. Of 15 patients with cough, 9 had an improvement in cough, and of 15 patients with dyspnea, 11 had an improvement. Thoracic reirradiation is an effective modality in patients with hemoptysis, thoracic pain, cough, and dyspnea attributed to a radiographically defined recurrence and/or progression of lung cancer.

Palliative treatment of epidemic kaposi sarcoma of the feet

Limited information is available in the medical literature on epidemic Kaposi sarcoma (EKS) of the foot. Patients with EKS of the foot can experience severe discomfort that makes it difficult to ambulate and even wear shoes. Between 1985 and 1996, 36 patients with EKS of the foot were treated with palliative intent. Most patients were referred for radiation therapy because of foot discomfort or marked difficulty with ambulation. From the pool of 36 patients, data were available at completion of treatment for 46 sites, and at 1 month for 44 sites. Morbidity was assessed for 35 sites. The median follow-up time for the 44 sites with at least 1 month follow-up was 8 months. The most frequently used regimen was a novel fractionation schedule of three fractions a week at 3.5 Gy/fx to a total dose of 21.0 Gy. The overall response rate and complete response rate for the 44 sites with at least 1 month follow-up were 91% and 80%, respectively. The 46 treated sites evaluated at the completion of treatment had a complete response rate of only 13% and an overall response rate of 63%. Of the 35 sites assessed for acute toxicity, 63% experienced discomfort related to the radiation therapy. This discomfort usually resolved without intervention within 2 weeks of completion of radiation therapy. For patients with and without a history of opportunistic infections, complete responses were observed in 8 of 12 sites (67%) and 25 of 27 sites (93%), respectively (p = 0.06). Radiation therapy for EKS of the foot yields excellent response rates, comparable with responses seen in other cutaneous sites with EKS. Appropriate patient education and support are needed because initial responses to radiation therapy are often disappointing and pedal discomfort can be exacerbated transiently. However, the discomfort resolves and complete response occurs in most patients. The 3.5-Gy triweekly fractionation schedule is a convenient and effective regimen and minimizes treatment visits for patients with ambulatory discomfort. A history of opportunistic infections appears to be a poor prognosticator of response to radiation treatments.

Variability in glucose transporter-1 levels and hexokinase activity in human melanoma.

Melanoma exhibits heterogeneous growth patterns and widely varying sensitivities to multiple treatment modalities. This variability may reflect intrinsic genetic differences in factors giving rise to altered metabolism. Glucose is the primary energy source of tumours, including melanoma, and glucose transporter isoform 1 (Glut-1) and hexokinase are key rate-limiting factors in glucose metabolism. The levels of Glut-1 and total hexokinase activity were measured in 31 melanoma biopsies to determine the extent of tumour-to-tumour variability in these parameters. Relative Glut-1 levels were determined by Western immunoblot analysis using human anti-Glut-1 rabbit polyclonal antibody, and hexokinase activity was measured in the same samples by an enzymatic assay monitoring the reduction in the oxidized form of nicotinamide adenine dinucleotide phosphate (NADP+) (in nmol NADP+ reduced/min per mg protein). All melanomas were from patients who had received no therapy prior to surgery. Immediately after excision, tumour biopsies were disaggregated to single cells by collagenase and DNase and frozen in liquid nitrogen. Thirty human melanomas exhibited a 22-fold variation in levels of Glut-1 and 29 exhibited a nine-fold variation in total cellular hexokinase activity. Glut-1 levels and hexokinase activity were not correlated with one another. The broad range in Glut-1 levels and hexokinase activity observed between melanomas suggests that these glycolytic rate-limiting parameters that influence the rate of glucose metabolism may contribute to the variability in melanoma response to treatment modalities.

Pilomatrix carcinoma of the thoracic spine: case report and review of the literature.

Abstract Context: Pilomatrixoma is a common head and neck neoplasm in children. Its malignant counterpart, pilomatrix carcinoma, is rare and found more often in men. Method: Case report of a 21-year-old man with pilomatrixoma of the thoracic spine that underwent malignant degeneration, to pilomatrix carcinoma. Findings: The appearance of a painless mobile axillary mass was followed by severe back pain 1 year later. Imaging revealed a compression fracture at the T5 level. The patient underwent resection of the axillary mass and spinal reconstruction of the fracture; the pathology was consistent with synchronous benign pilomatrixomas. Three months later he presented with a recurrence of the spinal lesion and underwent further surgical resection; the pathology was consistent with pilomatrix carcinoma. He received adjuvant radiotherapy and at his 1-year follow-up examination had no sign of recurrence. Conclusion/Clinical Relevance: Pilomatrix carcinoma involving the spine is a rare occurrence. It has a high incidence of local recurrence, and wide excision may be necessary to reduce this risk. Radiotherapy may be a helpful adjuvant therapy. Clinicians should be aware of this entity because of its potential for distant metastasis.

Impact of transrectal ultrasound- and computed tomography-based seed localization on postimplant dosimetry in prostate brachytherapy

PURPOSE To study the impact of seed localization, as performed by different observers using linked (125)I seeds, on postimplant dosimetry in prostate brachytherapy and, to compare transrectal ultrasound (TRUS)-based with CT-based approach for the dosimetric outcomes. METHODS AND MATERIALS Nineteen permanent prostate implants were conducted using linked (125)I seeds. Postimplant TRUS and CT images were acquired and prostate glands were, after implantation, delineated on all images by a single oncologist, who had performed all 19 seeding procedures. Six observers independently localized the seeds on both TRUS and CT images, from which the principle dosimetric parameters V(100) (volume of prostate that received the prescribed dose), V(150) (volume of prostate that received 150% of the prescribed dose), and D(90) (minimal dose delivered to 90% of the prostate) were directly calculated for each patient. A single-factor analysis of variance was first applied to determine interobserver variability in seed localization. A nonparametric comparison of the approach using TRUS and CT was then carried out by the Wilcoxon paired-sample test. RESULTS Analysis from the analysis of variance for TRUS showed that the null hypothesis for equal means, could not be rejected for all six observers based on a significance level alpha=0.05. TRUS-based and CT-based approaches were then cross compared by the Wilcoxon paired-sample test, which suggested that the null hypothesis was insignificant for V(100) and D(90), but was significant for V(150). CONCLUSIONS Both TRUS- and CT-imaging modalities provided indistinguishable postimplant dosimetry results as far as V(100) and D(90) were concerned. There was comparable observer independence between TRUS- and CT-based seed localization for linked-seed implant procedures. With other advantages that TRUS-imaging modality had over CT in the evaluation of postimplant dosimetry, TRUS would be a preferred choice in conjunction with linked seeds for intraoperative procedures in prostate brachytherapy.

SU-GG-T-48: Impact of Seed Localization On Post-Implant Dosimetry in Prostate Brachytherapy

Purpose: To study the impact of seed localization, as performed by different observers using linked I‐125 seeds, on post‐implant dosimetry in prostate brachytherapy and to compare TRUS‐based with CT‐based approach for the dosimetric outcomes. Method and Materials: Permanent prostate implant is conducted using linked I‐125 seeds. Both post‐implant TRUS and CTimages were acquired and the prostate glands were delineated on each of those images by a single oncologist, who performed the seeding procedures for all 19 patients under study. Six observers then independently localized the seeds on both TRUS and CTimages, based on which the principle dosimetric parameters V100, V150 and D90 were directly calculated for each patient. A single‐factor analysis of variance (ANOVA) is first applied to determine inter‐observer variability in seed localization. A non‐parametric comparison of the approach using the two imaging modalities, TRUS and CT, is then carried out by the Wilcoxon paired‐sample test. Results: Analysis from the ANOVA for TRUS (V100: P=0.655; V150: P=0.994; D90: P=0.734) and CT (V100: P=0.901; V150: P=0.999; D90: P=0.99) shows that the null hypothesis for equal means, cannot be rejected for all six observers based on a significance level α=0.05. TRUS‐based and CT‐based approaches are then cross‐compared by the Wilcoxon paired‐sample test, which suggests that the null hypothesis is not rejectable for V100 and D90, but is for V150. Conclusion: Both TRUS and CTimaging modalities provide indistinguishable post‐implant dosimetry results as far as V100 and D90 are concerned. TRUS‐based seed localization has comparable observer independence as CT‐based seed localization for linked‐seed implant procedures. In view of other advantages that TRUSimaging modality has over CT in the evaluation of post‐implant dosimetry,TRUS can therefore be an alternative gold standard to CT and would be a preferred choice together with linked‐seed for intra‐operative procedures ins prostate brachytherapy.

SU‐GG‐T‐20: Dosimetric Analysis and Comparison of Cesium‐131 and Iodine‐125 for Permanent Prostate Brachytherapy

Purpose: To perform a dosimetric analysis and comparison of Cesium‐131 and Iodine‐125 for permanent prostate brachytherapy.Method and Materials:TRUS prostate volume studies of 30 patients treated in our institution with a wide range of prostate size were included in this study. The average gland size was 31.13cc (from 15.22cc to 51.49cc). Treatment plans were generated using Variseed 7.1 with both Cesium‐131 (with an activity of 2.1U, prescription of 115 Gy) and Iodine‐125 (with an activity of 0.521U, prescription of 145 Gy). Prostate, rectum, urethra were contoured by the same radiation oncologist. The Auto Source Placement tool of the software was first used to create treatment plans for both Cesium‐131 and Iodine‐125. The plans were then adjusted to meet the treatment goals and achieve the same dose coverage (V100, V90, D90) of the prostate for both isotopes. The dose to the prostate (V100, V90, V80, D90), rectum (RV100, RD10), urethra (UD10), and dose inhomogeneity (V150, V200) were reported. Results: For 30 patients, the average of V100, V90, V80, D90 for the prostate was 98.58%, 99.46%, 99.95%, 134.7 Gy and 98.49%, 99.57%, 99.87%, 170.4 Gy for Cesium‐131 and Iodine‐125 respectively. V200 and V150 of prostate were 22.06%, 49.20% for Cesium‐131, and 22.57%, 51.38% for Iodine. UD10 and RD10 were 81.17%, 127.79% of the prescription for Cesium‐131, and 82.58%, 129.44% of the prescription for Iodine. There was a decrease of 27.5% rectum RV100 (0.24cc for Cesium, and 0.33 for Iodine, with a p‐value of 0.05) when planning for Cesium‐131 as compared to Iodine‐125. Conclusion: Cesium‐131 prostate brachytherapy can provide a homogeneous dose distribution, dose coverage compared with Iodine‐125 seeds implant, while reducing the overall dose to the rectum. Large volume of patient studies is needed to validate this statement.

2223 Effective palliative treatment of Epidemic Kaposi's Sarcoma of the foot

PURPOSE: Limited information is available in the medical literature on Epidemic Kaposi’s Sarcoma (EKS) of the foot. A considerable amount of distress is experienced from EKS of the foot because minimal disease can cause severe discomfort, making it difficult to ambulate and even wear shoes. Various fractionation schemes and doses have been proposed to palliate these patients. The limiting factor for higher dose regimens appears to be the acute toxicity of foot discomfort which is experienced towards the end of treatment. Even doses as low as 20.0 Gy at 2.0 Gylfx have been associated with transient episodes of generalized foot pain followed by desquamation of the skin of the sole in 5/7 patients treated to the foot at Los Angeles County Hospital (JCO 6:863-867, 1988). In fact, Piedbois et al. (IJROBP 30: 1207-1211, 1994) discontinued treatment to the foot if a partial remission was appreciated with split course radiation therapy to 20.0 Gy to lessen the risk of morbidity. These observations prompted us to review the treatment results of radiation therapy for EKS of the foot at our institutions.