Efficacy of Single-Fraction Postoperative Radiotherapy in Resected, Early-Stage Merkel Cell Carcinoma with High-Risk Features

PURPOSE/OBJECTIVE(S)

Merkel cell carcinoma (MCC) is an aggressive skin cancer with a high recurrence risk. Postoperative radiotherapy (PORT) improves the local recurrence rate (LRR) in early-stage MCC with risk factors per NCCN guidelines: primary tumor size > 1cm, head/neck (HN) location, immunosuppression, lymphovascular invasion (LVI), and positive/narrow surgical margins. Conventionally fractionated PORT (C-PORT, ∼50 Gy in 25 fractions) is often recommended for localized MCC with these risk factors; however, some institutions elect observation. Prior studies suggest LRR of ∼20% for stage I/II MCC with high-risk features managed with surgery alone. C-PORT significantly decreases LRR but may cause significant morbidity and financial toxicity. We have previously reported that single fraction (SF)-PORT with 8 Gy achieves high rates of in-field control both in the metastatic and adjuvant settings with minimal morbidity. Here, we present updated long-term outcomes of SF-PORT, offered as an alternative to C-PORT with the hypothesis that it improves LRR relative to observation while minimizing toxicity, for resected stage I/II MCC.

MATERIALS/METHODS

A retrospective, single-institution analysis was completed for stage I/II MCC patients receiving SF-PORT following surgical management. The primary objective was estimating the LRR, defined as recurrence within 2 cm of the primary tumor. Patients with resected, stage I/II MCC with at least one high-risk feature were offered C-PORT as standard of care or SF-PORT as an alternative.

RESULTS

Forty-six patients (median age: 74.5; range 50-96 years) received SF-PORT to the primary tumor site at a median 44 days after wide local excision (85%), shave/excisional biopsy (13%), or Mohs (2%). Fifty-four percent of patients had 1 high-risk feature, 35% had 2, and 11% had 3 or more. HN (74%) was the most common primary site, 26% of tumors were > 1cm, 26% were LVI+, and 15% of patients were immunosuppressed (pathological margin status was often not available). There were no local recurrences (LRR = 0%) at a median follow-up time of 2.3 years. In-field locoregional control was 96% (44/46 patients) with 2 in-field, regional recurrences observed in draining nodal basins of HN primary lesions. There were 2 out-of-field regional nodal recurrences (1 patient with IMS; neither received elective nodal SFRT). Of 9 patients who received elective nodal SF-PORT, 8 did not have a successful sentinel lymph node biopsy. No MCC-specific deaths were observed. The most common side effect was in-field, grade 1 erythema (13%); no side effects > grade 1 (CTCAE v5) were noted.

CONCLUSION

SF-PORT is associated with a very low LRR which has proven durable with long-term follow-up. The LRR for SF-PORT appears lower than historical controls treated with surgery alone for patients with resected, stage I/II MCC with high-risk features.

Uptake of Neonicotinoid Insecticides by Water-Foraging Honey Bees (Hymenoptera: Apidae) Through Guttation Fluid of Winter Oilseed Rape

The water-foraging activity of honey bees (Apis mellifera L.) on guttation fluid of seed-coated crops, such as winter oilseed rape (WOR; Brassica napus L.), has not yet been evaluated. We analyzed the uptake of active substances (a.s.) in guttation fluid by evaluating residues of honey-sac contents. In autumn, insecticide residues of up to 130 µg a.s. per liter were released in WOR guttation fluid; this concentration is noticeably lower than levels reported in guttation fluid of seed-coated maize. Until winter dormancy, the concentrations declined to <30 µg a.s. per liter. In spring, residues were linked to prewintered plants and declined steadily until flowering. The maximum release of residues in guttation fluid of seed-coated WOR occurs on the first leaves in autumn when the colonies' water demand decreases. For the first time, proof for the uptake of guttation fluid from seed-coated WOR by honey bees was provided by measuring residues in individual honey-sac contents. In total, 38 out of 204 samples (19%) showed residues of thiamethoxam at concentrations ranging from 0.3 to 0.95 µg per liter while the corresponding concentrations in guttation fluid of WOR varied between 3.6 to 12.9 µg thiamethoxam per liter. The amounts of thiamethoxam we found in the honey sacs of water-foraging honey bees were therefore below the thresholds in nectar and pollen that are considered to have negative effects on honey bees after chronic exposure.

239 A NOVEL PIG MODEL OF CYSTIC FIBROSIS GENERATED BY SEQUENTIAL TARGETING OF CFTR BY BACTERIAL ARTIFICIAL CHROMSOME VECTORS

Cystic fibrosis (CF), the most common inherited disease in the Caucasian population, is caused by mutations of the CFTR gene, coding for an anion channel responsible for chloride movement, determining transepithelial salt transport, fluid flow and ion concentrations. Cystic fibrosis is determined by chronic lung disease, marked by airway surface dehydration, reduced mucus clearance and increased mucus obstruction, impaired bacterial killing and inflammation and continuous destruction of the lung tissue. The lack of suitable CF mouse models has so far impeded the understanding of disease mechanisms and the development of novel therapies. Recently, a pig model reflecting the main hallmarks of the human disease in the respiratory, gastrointestinal and genital tracts has been reported (Rogers et al. 2008 Science 321, 1837–1841). In the present study, we generated a new CF pig model by disrupting the CFTR gene using an approach that differs in 3 major aspects from the previously published model: (1) gene targeting was achieved using a modified bacterial artificial chromosome (BAC) vector; (2) transcription of the CFTR gene was completely prevented; and (3) homozygous CFTR mutant pigs were derived by nuclear transfer from cells in which both alleles were inactivated by sequential BAC targeting. We characterised 2 cloned litters with a total of 13 piglets (including 4 stillborns). All piglets showed a characteristic CF multi-organ disease with severe meconium ileus, microcolon, microgallbladder, hypoplasia of the exocrine pancreas, congenital aplasia of the vas deferens and malformations of the trachea. In contrast to the recently published CF pig, where the majority of the intestinal obstructions occurred proximal to the ileocecal junction, we found obstructions exclusively distal to this site. We thus present a novel pig model for CF that reflects the main hallmarks of the human disease. It confirms the suitability of the CFTR mutant pig for cystic fibrosis research and increases the availability of CF models for molecular and translational CF research. The help by Prof. K. Heinritzi and his team from the Pig Clinic, LMU Munich, is gratefully acknowledged. This study was supported by Mukoviszidose e.V.

338 BACTERIAL ARTIFICIAL CHROMOSOME (BAC) VECTORS FACILITATE EFFICIENT GENE TARGETTING IN KIDNEY CELLS OF PIG

Site-directed mutagenesis provided a powerful tool for studying gene functions in mice, but the lack of embryonic stem cells in other species limited the application of this technology to other species. Various attempts using negative selection, viral vectors, or other auxiliary means promoted specific projects but did not provide methods for routine experiments. Here, we describe a novel approach that enabled the site-directed modification of 3 different porcine genes relevant for biomedical research. Three main technologies were combined to achieve these goals: bacterial artificial chromosome (BAC) vectors, somatic cell transfection, and nuclear transfer (SCNT). BAC vectors contain large genomic regions in bacterial plasmids. They are superior to conventional targeting tools, as they provide extended regions of homology of several kilobases. Novel recombination tools using bacterial enzymes enable the modification of any DNA region of interest and thus allow the introduction of desired mutations into BACs. After verification of the wt-BAC sequence, it was altered by using modification vectors carrying the desired mutation. The modified BAC vectors are linearized and transfected after verification into primary kidney cell lines, and cells are selected for integration of the vectors. Kidney cells provide both good proliferation and high targeting rates, and thus improve the efficiency compared to fetal fibroblasts. Singularized clones are screened for the replacement of wild-type targeting loci by quantitative PCR. Targeted clones are used for SCNT and transfer of the resulting embryos into synchronized gilts. We have evaluated this technology by the modification of the porcine CFTR, GGTA1, and DMD genes. All 3 genes are relevant for biomedical research, as mutations in CFTR are causative for cystic fibrosis, the knockout of GGTA1 is essential for overcoming hyperacute rejection in xenotransplantation, and various deletions in the DMD gene are responsible for Duchenne muscular dystrophy. Gaining 13 targeted clones out of 1152 for CFTR, 9 out of 306 for GGTA1 and 6 out of 203 for DMD, we obtained efficiencies higher than 1% for each of the target genes. The power of our approach is underlined by the fact that CFTR and DMD are loci that are thought to be difficult to manipulate. The viability of targeted kidney cells and their suitability for nuclear transfer is accentuated by the pregnancy rates (2 out of 3) and the delivery of 4 to 10 piglets or fetuses in the case of CFTR and GGTA1. The heterozygous fetuses or piglets are verified by qPCR. In the case of the X-chromosomal DMD gene, we have generated the first full knockout by transfecting male cells. Pregnancies of a successfully targeted clone are under way. Thus, we consider the combination of modified BAC vectors, transfection of kidney cells, and nuclear transfer to be a technology with the potential for routine production of site-directed mutations. Supported by the Mukoviszidose e.V. and the Bayerische Forschungsstiftung.

Effect of obesity on overall survival following permanent prostate brachytherapy

15576

Background: To evaluate the impact of obesity on cause-specific (CSS), biochemical progression-free (bPFS) and overall survival (OS) following prostate brachytherapy. Methods: From April 1995 through March 2003, 1,093 consecutive patients underwent brachytherapy for clinical T1b-T3a (2002 AJCC) prostate cancer. The median follow up was 5.6 years. All patients were implanted at least 3 years prior to analysis. Evaluated body mass index (BMI) subgroups were < 25 (n=258), 25.0 to 29.9 (n=547), 30.0 to 34.9 (n=214) and = 35 (n=74) kg/m2, respectively. Four-hundred and thirty (39.9%) and 589 (53.9%) of the patients received androgen deprivation therapy or supplemental external beam radiation therapy, respectively. Multiple clinical, treatment and dosimetric parameters were evaluated as predictors of CSS, bPFS and OS. Results: The 11 year CSS, bPFS and OS for the entire cohort were 97.5%, 95.6% and 77.6% respectively. BMI did not impact CSS or bPFS for any of the BMI cohorts. However, OS was statistically lower in patients with a BMI < 25 kg/m2 (p = 0.014). A Cox linear regression analysis demonstrated that Gleason score was the best predictor of CSS while percent-positive biopsies, risk group,V100 and hypertension predicted for bPFS. Patient age and tobacco use were the strongest predictors of OS. One-hundred and twenty-eight patients have died with 108 (84.4%) of the deaths the result of cardiovascular/pulmonary disease (73) and second malignancies (35). To date, 12 patients have died of metastatic prostate cancer. Conclusions: Following brachytherapy, obesity did not impact CSS, bPFS or OS. Cardiovascular or pulmonary disease and second malignancies substantially outweighed prostate cancer as competing causes of death.

No significant financial relationships to disclose.

The impact of primary Gleason pattern on survival following brachytherapy for Gleason score 7 prostate cancer

15588

Background: A recent radical prostatectomy series reported lower rates of biochemical control and cause-specific survival in Gleason score 7 patients with primary Gleason pattern 4. In this study, we evaluated the impact of Gleason 4+3 versus 3+4 on cause-specific, biochemical progression-free and overall survival in patients managed with permanent prostate brachytherapy. Methods: From April 1995 to June 2003, 530 prostate cancer patients underwent brachytherapy for clinical stage T1b-T3c (2002 AJCC) prostate cancer with Gleason score 3+4 (n=300) or Gleason score 4+3 (n=230) histology. All patients underwent brachytherapy more than three years prior to analysis. The mean and median follow-up was 6.0 and 5.7 years, respectively (range 3.2–11.2 years). Of the evaluated cohort, 412 (77.7%) received supplemental XRT and 177 (33.4%) received androgen deprivation therapy. No statistical differences were discerned between the use of XRT, however, Gleason 4+3 patients were more likely (37.4% versus 30.3%, p=0.002) to receive ADT. Multiple clinical, treatment and dosimetric parameters were evaluated as predictors of cause-specific, biochemical progression-free and overall survival. Results: At 10 years, primary Gleason 3+4 versus 4+3 did not predict for cause-specific survival (96.7% versus 93.3%, p=0.506), biochemical progression-free (97.0 versus 92.9%, p=0.085) or overall survival (77.0% versus 78.0%, p=0.9333). Cox linear regression analysis demonstrated no significant predictors for cause-specific survival while pre-treatment PSA, prostate volume and clinical stage predicted for biochemical progression-free survival. Patient age, tobacco use and diabetes were the strongest predictor for overall survival. To date, 57 patients have died (25 with Gleason 4+3 and 32 with Gleason 3+4). Of the deaths, 76% were due to cardiovascular events or second malignancies. To date, 4 patients (2 in each cohort) have died of metastatic prostate cancer. Conclusions: Following brachytherapy, the primary Gleason pattern did not impact cause-specific, biochemical progression-free or overall survival in Gleason score 7 prostate cancer. Cardiovascular disease and second malignancies were responsible for 9 times more deaths than prostate cancer.

No significant financial relationships to disclose.

Androgen deprivation therapy does not impact cause-specific or overall survival in high-risk prostate cancer treated with brachytherapy and supplemental external beam

15578

Background: To determine cause-specific (CSS), biochemical progression-free (bPFS) and overall survival (OS) in high risk prostate cancer patients undergoing brachytherapy with or without supplemental therapies. Methods: From April 1995 through July 2002, 204 patients with high risk prostate cancer (Gleason score = 8 and/or PSA > 20 ng/mL and/or clinical stage = T2c) underwent brachytherapy with or without supplemental therapies. Of the 204 patients, 193 (94.6%) received supplemental XRT and 119 (58.3%) received ADT (ADT = 6 months n=40 and ADT > 6 months n = 79). Median follow-up was 7.0 years. All patients were implanted at least 4 years prior to analysis. BPFS was defined by a PSA = 0.40 ng/mL after nadir. Multiple clinical, treatment and dosimetric parameters were evaluated for the impact on survival. Results: The ten-year CSS, bPFS and OS were 88.9%, 86.6% and 68.6%, respectively. A statistically significant difference in bPFS was discerned between hormone naïve, ADT = 6 months and ADT > 6 month cohorts (79.7% vs. 95.0% vs. 89.9%, p= 0.032). ADT did not impact CSS (94.0% vs. 87.1%, p=0.983 ) or OS (65.2% vs. 70.3%, p = 0.713). For bPFS patients, the median post-treatment PSA was < 0.04 ng/mL. A Cox linear regression analysis demonstrated that Gleason score was the best predictor of CSS while percent positive biopsies and duration of ADT best predicted for bPFS. OS was best predicted by Gleason score and diabetes. Thirty-eight patients have died with 26 of the deaths due to cardiovascular/pulmonary disease or second malignancy. Eleven patients have died of metastatic prostate cancer. Conclusions: Androgen deprivation therapy improved 10-year bPFS without statistical impact on CSS or OS. Death as a result of cardiovascular/pulmonary disease and second malignancies were more than twice as common as prostate cancer deaths. Strategies to improve cardiovascular health should positively impact overall survival.

No significant financial relationships to disclose.

Prostate cancer distribution in patients diagnosed by transperineal template-guided saturation biopsy: Implications for brachytherapy treatment planning

15533

Background: Prostate cancer remains undetected in approximately one-third of patients following standard transrectal ultrasound-guided biopsy. In this study, we evaluated prostate cancer incidence, anatomic distribution, Gleason score profile and tumor burden in patients diagnosed by transperineal template-guided saturation biopsy (TTSB). Methods: One hundred and seventeen patients underwent TTSB. TTSB was performed under general anesthesia. All but one patient had undergone at least one prior negative TRUS biopsy. Criteria for inclusion included an elevated PSA and/or the diagnosis of ASAP or high-grade PIN on prior biopsy. The prostate gland was divided into 24 regional biopsy locations with 1–3 biopsies per region. The median number of biopsy cores was 50. Multiple clinical parameters were evaluated as predictors for prostate cancer diagnosis. Results: The mean patient age was 64.8 years with a mean PSA of 9.1 ng/mL and a prostate volume of 78.6 cm3. On average, patients had undergone 2.1 prior negative TRUS biopsies with a mean of 22.4 core biopsies. Prostate cancer was diagnosed in 49 patients (41.9%) with a Gleason score distribution of 6–9. Patients with a prostate volume of = 60 cm3 had a higher rate of cancer diagnosis compared to patients with larger glands (66% vs. 30%). Although no anatomic region of the prostate gland was spared of cancer, there was a preponderance of anterior-based malignancies. In patients with prostate cancer, an average of 9.9 cores were involved. In multivariate analysis, pre-saturation biopsy diagnosis and prostate volume were the best predictors for prostate cancer diagnosis. Conclusions: Transperineal template-guided saturation biopsy diagnosed prostate cancer in 41.9% of previously biopsied patients. Considerable anatomic variability in prostate cancer distribution was documented. Based on this and other reports, cancer eradication will be dependent on treatment of the entire prostate gland.

No significant financial relationships to disclose.

Prediction of PSA spikes by isotope and patient age following permanent prostate brachytherapy

15535

Background: To evaluate prostate specific antigen (PSA) spikes (bounces) following permanent prostate brachytherapy in low-risk patients randomized to Pd-103 or I-125. Methods: The study population consisted of 164 prostate cancer patients who were part of a prospective randomized trial comparing Pd-103 with I-125 for low-risk disease. Sixty-one patients (37.2%) received short course cytoreductive androgen deprivation therapy (ADT). No patient received supplemental XRT. The median follow-up was 5.4 years. All patients were implanted at least 3 years prior to analysis. On average, 10.1 post-treatment PSA’s were obtained per patient. Biochemical disease-free survival was defined as a PSA = 0.40 ng/mL after nadir. A PSA spike was defined as a rise of = 0.2 ng/mL followed by a durable decline to pre- spike levels. Multiple clinical, treatment and dosimetric parameters were evaluated as predictors for a PSA spike. Results: Forty- four patients (26.9%) developed a PSA spike including 45.7% (21/46) of the hormone naïve I-125 patients and 14.0% (8/57) of the hormone naïve Pd-103 patients. In hormone naïve patients, the mean time between implant and spike was 22.6 months and 18.7 months for I-125 and Pd-103 patients, respectively. In patients receiving neoadjuvant ADT, the incidence of spikes was comparable between isotopes (28.1% for I- 125 and 20.7% for Pd-103). The incidence of spikes was substantially different in patients < 65 vs = 65 years of age (16.3% vs. 38.5%). In multivariate Cox regression analysis, patient age at implant (p < 0.001) and isotope (p = 0.002) were significant predictors for spike. Conclusions: In low-risk prostate cancer patients, PSA spikes are most common in patients implanted with I-125 and/or younger than 65 years of age. Differences in isotope-related spikes are most pronounced in hormone naïve patients.

No significant financial relationships to disclose.

Preexisting histologic evidence of prostatitis is unrelated to postimplant urinary morbidity

The presence and extent of prostatitis on the patients' preimplant biopsy slides was correlated with their postimplant course to determine if any relationship exists between histological prostatitis and postimplant morbidity. Biopsy slides from 56 patients treated with I-125 (144 Gy, TG-43), Pd-103 (125 Gy, NIST-1999), or Pd-103 plus supplemental external beam radiation (20-44 Gy) were studied. As part of ongoing prospective protocols, treatment-related morbidity is monitored by mailed questionnaires at 1, 3, 6, 12, and 24 months postimplant, using standard American Urologic Association (I-PSS) and Radiation Therapy Oncology Group criteria. Patient's preimplant biopsies, stained with standard hematoxylin and eosin, were retrieved for review by one uropathologist (LT). Separate evaluations of the degree and extent of inflammation in biopsy cores free of cancer and in cancerous biopsy cores were undertaken. Infiltrates were classified as periglandular if they were within 50 microns of a glandular structure. They were otherwise classified as stromal. Distribution of the inflammation was reported as focal, multifocal, or diffuse. The intensity of inflammation was separately graded as mild if there were fewer than 10 inflammatory cells per high-power field, moderate if there were 10-200 cells per high-power microscopic field, or severe if there were more than 200 cells per field. In all cases the great majority of inflammatory cells were mononuclear, predominantly lymphocytes. Periglandular inflammation was most common, with 18% of patients having focal periglandular and 20% having multifocal periglandular inflammation on their preimplant biopsies. Cancer-related infiltrates were the second most common, with 23% of patients having focal, 13% multifocal, and 13% diffuse cancer-related inflammation on their preimplant biopsies. Eight of the 55 patients developed postimplant urinary retention, requiring catheterization for 2 to 8 days. The overall incidence of postimplant urinary retention was low and there was no obvious relationship between the presence of inflammation on preimplant biopsy and the likelihood of postimplant urinary retention. AUA score changes at 1 and 6 months postimplant were highly variable and unrelated to the presence or severity of periglandular or cancer-related inflammation. Considering the apparent lack of relationship between histological findings and clinical outcomes in the patients reported here, the authors conclude that histologic evidence of prostatitis is not a contraindication to brachytherapy.

Long-term urinary function after transperineal brachytherapy for patients with large prostate glands

PURPOSE

To summarize longer-term postbrachytherapy morbidity in patients with prostate glands >50 cm3.

METHODS AND MATERIALS

From 1997 to 1998, 33 patients with a transrectal ultrasound-based prostate volume >50 cm3 were treated at the University of Washington by 125I (144 Gy) or 103Pd (115 Gy) implantation for prostate carcinoma. These 33 patients comprised 7% of the total implant patient population. Twelve patients were treated with neoadjuvant androgen ablation before implantation. The (125)I source strength ranged from 0.34 to 0.5 mCi and the 103Pd source strength ranged from 1.1 to 1.4 mCi (pre-NIST-99). The total number of sources implanted was 94-223 (median 155). Despite the typical implant-related volume increase, the postimplant CT-defined prostate volumes were generally well-covered by the prescription isodose (median coverage 92%, range 80-100%). The preimplant urinary obstructive symptoms were quantified by the criteria of the American Urological Association.

RESULTS

Of the 33 patients, 12 developed acute postimplant urinary retention, all presenting within 24 h of implantation. Patients who developed postimplant retention lasting >1 week were generally treated with intermittent self-catheterization. By 1 month, 85% of patients were catheter free. By 1 year, only 1 patient (4%) remained in urinary retention; the remainder of cases had resolved spontaneously. With follow-up of 1.7-2.6 years, the last American Urological Association scores were higher than the pretreatment scores in 15 patients and lower in 7 patients. No patient developed permanent urinary incontinence. Long-term changes in the American Urological Association scores were unrelated to whether the patient had been in urinary retention after implantation. Two patients developed rectal fistulas; they had preimplant transrectal ultrasound prostate volumes of 53 and 59 cm3, in the low range for this group of patients. No other patient had persistent rectal bleeding suggestive of clinically significant proctitis. The pretreatment serum prostate-specific antigen level was 3.3-15 ng/mL (median 7.2) and the last serum prostate-specific antigen level 0.1-1.6 ng/mL (median 0.2).

CONCLUSION

Patients with larger prostate volumes appear to have moderate morbidity and a satisfactory technical outcome with brachytherapy. We do not believe the occurrence of two severe rectal complications was related to the prostate volume per se. Our experience and that of others calls into question the validity of using prostate volume as a criterion for patient suitability for prostate brachytherapy.

Argon plasma coagulation for rectal bleeding after prostate brachytherapy

PURPOSE

To better define the efficacy and safety of argon plasma coagulation (APC), specifically for brachytherapy-related proctitis, we reviewed the clinical course of 7 patients treated for persistent rectal bleeding. Approximately 2-10% of prostate cancer patients treated with 125I or 103Pd brachytherapy will develop radiation proctitis. The optimum treatment for patients with persistent bleeding is unclear from the paucity of available data. Prior reports lack specific dosimetric information, and patients with widely divergent forms of radiation were grouped together in the analyses.

METHODS AND MATERIALS

Seven patients were treated with APC at the Veterans Affairs Puget Sound Health Care System and the University of Washington from 1997 to 1999 for persistent rectal bleeding due to prostate brachytherapy-related proctitis. Four patients received supplemental external beam radiation, delivered by a four-field technique. A single gastroenterologist at the Veterans Affairs Puget Sound Health Care System treated 6 of the 7 patients. If the degree of proctitis was limited, all sites of active bleeding were coagulated in symptomatic patients. An argon plasma coagulator electrosurgical system was used to administer treatments every 4-8 weeks as needed. The argon gas flow was set at 1.6 L/min, with an electrical power setting of 40-45 W.

RESULTS

The rectal V100 (the total rectal volume, including the lumen, receiving the prescription dose or greater) for the 7 patients ranged from 0.13 to 4.61 cc. Rectal bleeding was first noticed 3-18 months after implantation. APC (range 1-3 sessions) was performed 9-22 months after implantation. Five patients had complete resolution of their bleeding, usually within days of completing APC. Two patients had only partial relief from bleeding, but declined additional APC therapy. No patient developed clinically evident progressive rectal wall abnormalities after APC, (post-APC follow-up range 4-13 months).

CONCLUSIONS

Most patients benefited from APC, and no cases of clinically evident progressive tissue destruction were noted. Although APC appears to be efficacious and safe in the setting of the rectal doses described here, caution is in order when contemplating APC for brachytherapy patients.

Short-term sexual function after prostate brachytherapy

Sexual function was evaluated in 34 patients with low-risk prostate cancer (PSA < or = 10, Gleason score < or = 6, clinical stage T1/T2) undergoing brachytherapy in a phase III prospective randomized trial comparing iodine-125 ((125)I) to palladium-103 ((103)Pd). The mean and median International Index of Erectile Function (IIEF) scores for the entire group were 14.2 and 16.5, respectively, and there was no difference between these scores when stratified by isotope. IIEF scores < 6, 6 to 11, and > or = 12 were recorded in 35% (12/34), 6% (2/34), and 59% (20/34) of patients, respectively. Hematospermia, orgasmalgia (pain at the time of orgasm), and alteration in intensity of orgasm were documented in 26% (9/34), 15% (5/34), and 38% (13/34) of patients, respectively, but these side effects were of limited duration for most patients. There was no relationship between radiation dose to the neurovascular bundles (NVB), which averaged 209% of the prescribed prostate dose, and the development of postbrachytherapy impotence. All four impotent patients who used sildenafil responded favorably. With a median follow-up of 13 months, 65% of patients undergoing prostate brachytherapy maintained sexual function without pharmacologic support. Including sildenafil responses, 76.5% of patients sustained erections sufficient for sexual intercourse.

Patient reported complications after prostate brachytherapy

PURPOSE

Prostate brachytherapy has gained popularity due partly to the low rates of short-term complications shown in studies from highly select clinical practices. These series rely on medical records generated by the treating physician and are prone to underreport complications. We summarize the complication reports obtained directly from patients to establish a more realistic incidence of treatment related problems.

MATERIALS AND METHODS

In 1997, 160 consecutive patients treated with prostate brachytherapy at the University of Washington were studied. A questionnaire was designed to determine the rate of complications occurring within 1 year of the procedure. The questions were formulated for ease of use and conciseness, while accounting for easily recalled events associated with complications. A total of 147 (92%) patients completed the questionnaire.

RESULTS

There were 8 (5%) patients who required hospital admission for an average of 2 days (range 1 to 7) as a result of the procedure. A total of 56 (38%) patients required nonroutine visits with a physician in an office setting or at an emergency room. Radiation proctitis diagnosed by endoscopy developed in 8 (5%) patients but no one needed surgical intervention. A total of 47 (32%) patients required urinary catheterization at some point after implantation.

CONCLUSIONS

We demonstrated a higher rate of short-term complications than those previously reported. Fortunately, the majority of side effects were self-limited and no treatment related mortality or cardiovascular morbidity was seen. Our findings may provide a more realistic account of the complications likely to occur after implantation than might be surmised from previous reports.

Temporary PSA rises and repeat prostate biopsies after brachytherapy

PURPOSE

The long-standing confusion regarding the clinical relevance of postimplant biopsies is complicated by the common occurrence of temporary PSA rises between 1 and 2 years after brachytherapy. We report here 4 patients with temporary, self-limited PSA rises and postimplant biopsies, for whom radical prostatectomy was strongly advised but for whom surgery would probably have been the wrong choice.

MATERIALS AND METHODS

Transperineal I-125 or Pd-103 implants were performed as previously described. After implantation, patients were followed routinely, with repeat PSA and physical examination at approximately every 4 to 6 months. Timing of postimplant PSAs was at the discretion of the patient and his doctors. Postimplant biopsies were performed in all cases out of concern for a persistently elevated serum PSA. Sections of fixed and embedded tissue were stained with standard hematoxylin and eosin.

RESULTS

All 4 patients presented here were advised to have a salvage prostatectomy based primarily on their PSA changes. However, all of the patients have subsequently had a dramatic PSA fall, consistent with long-term cancer control, despite the fact that 3 of the 4 had histologic evidence of persistent cancer on repeat prostate biopsy.

CONCLUSIONS

It is crucial that clinicians be aware of the potential for the doubly confusing situation of temporary PSA rises and apparently positive rebiopsies and the pressure it puts on both patients and their physicians to go ahead with inappropriate salvage therapy.

A comparison of radiation dose to the bulb of the penis in men with and without prostate brachytherapy-induced erectile dysfunction

PURPOSE

To retrospectively evaluate the relationship between the radiation dose to the bulb of the penis and the development of erectile dysfunction (ED) in patients undergoing permanent prostate brachytherapy without external beam radiation therapy.

METHODS AND MATERIALS

Twenty-three men who developed ED after transperineal ultrasound-guided permanent prostate brachytherapy for clinical T1/T2 adenocarcinoma of the prostate gland were paired with 23 similar men who maintained potency after implantation. Potency was defined as an erection sufficient for vaginal penetration. The mean and median follow-up for the entire group was 34.6 +/- 13.7 months and 32.8 months, respectively. Patients were implanted with either (125)I (145 Gy TG-43) or (103)Pd (115 Gy, pre-NIST-99). No patient received external beam radiation therapy either before or after brachytherapy. The bulb of the penis was outlined at 0.5-cm intervals on the Day 0 postimplant CT scan. The radiation dose distribution to the bulb of the penis was defined in terms of the minimal dose delivered to 25%, 50%, 70%, 75%, 90%, and 95% of the bulb (D(25), D(50), D(70), D(75), D(90), and D(95)).

RESULTS

The radiation dose delivered to the bulb of the penis in men with postbrachytherapy-induced ED was statistically greater for all evaluated dosimetric parameters (D(25), D(50), D(70), D(75), D(90), and D(95)). Multivariate analysis indicated that dose to the bulb of the penis and patient age at the time of implant were predictive of postimplant ED, whereas choice of isotope had no effect. Among potent patients, 19/23 had D(50) < or = 40% of prescribed minimal peripheral dose, whereas for the impotent patients, 19/23 had D(50) >40% of the minimal peripheral dose. Of the impotent patients, 17 utilized sildenafil, with 15 experiencing a favorable response (88%).

CONCLUSION

Our data suggest that prostate brachytherapy-induced impotence is highly correlated with the radiation dose delivered to the bulb of the penis. With Day 0 dosimetric evaluation, the radiation dose delivered to 50% of the bulb of the penis should be maintained at 50 Gy or less to maximize post-treatment potency. Fortunately, the majority of the brachytherapy-induced ED population responds favorably to sildenafil.

Standardization of prostate brachytherapy treatment plans

PURPOSE

Whereas custom-designed plans are the norm for prostate brachytherapy, the relationship between linear prostate dimensions and volume calls into question the routine need for customized treatment planning. With the goal of streamlining the treatment-planning process, we have compared the treatment margins (TMs) achieved with one standard plan applied to patients with a wide range of prostate volumes.

METHODS AND MATERIALS

Preimplant transrectal ultrasound (TRUS) images of 50 unselected University of Washington patients with T1-T2 cancer and a prostate volume between 20 cc and 50 cc were studied. Patients were arbitrarily grouped into categories of 20-30 cc, 30-40 cc, and 40-50 cc. A standard 19-needle plan was devised for patients in the 30- to 40-cc range, using an arbitrary minimum margin of 5 mm around the gross tumor volume (GTV), making use of inverse planning technology to achieve 100% coverage of the target volume with accentuation of dose at the periphery and sparing of the central region. The idealized plan was applied to each patient's TRUS study. The distances (TMs) between the prostatic edge (GTV) and treated volume (TV) were determined perpendicular to the prostatic margin.

RESULTS

Averaged over the entire patient group, the ratio of thickness to width was 1.4, whereas the ratio of length to width was 1.3. These values were fairly constant over the range of volumes, emphasizing that the prostate retains its general shape as volume increases. The idealized standard plan was overlaid on the ultrasound images of the 17 patients in the 30- to 40-cc group and the V100, the percentage of target volume receiving 100% or more of the prescription dose, was 98% or greater for 15 of the 17 patients. The lateral and posterior TMs fell within a narrow range, most being within 2 mm of the idealized 5-mm TM. To estimate whether a 10-cc volume-interval stratification was reasonable, the standard plan generated from the 30- to 40-cc prostate model was applied to 5 patients each from the 20- to 30-cc group and the 40- to 50-cc group. Using the standard plan designed for the 30- to 40-cc group, the TMs were closer to 10 mm than to 5 mm for the smaller volume glands and too small for the larger volume ones, assuming an ideal margin of 5 mm.

CONCLUSION

The application of standardized plans to prostate brachytherapy is feasible. Stratifying the volume in 10-cc intervals appears to be adequate, suggesting that the majority of cases appropriate for treatment with brachytherapy might be treated with three standard plans. While the authors believe that the use of a limited number of standard treatment plans is feasible, practical, and medically acceptable, it should be emphasized that the use of a standard plan should always be previewed by computer-aided application to the particular patient's planning images.

IMPROVED OUTCOMES WITH RADIATION FOR PROSTATE CANCER

During the last 15 years, a series of substantial technical improvements have occurred in external beam radiation and brachytherapy. The introduction of PSA-based posttreatment monitoring has allowed a reasonable comparison between each radiation modality and prostatectomy. Such comparisons show more similarities than differences. Probably the most exciting finding in regard to curing cancer is that higher-risk patients have a more favorable prognosis than previously recognized using higher doses now achievable with either form of radiation.

Adventitial remodeling after angioplasty is associated with expression of tenascin mRNA by adventitial myofibroblasts

OBJECTIVES

The purpose of this study was to determine the temporospatial expression of tenascin-C (TnC) in balloon-injured rat and porcine arteries.

BACKGROUND

Recent studies suggest that cell migration, in addition to cell proliferation, is a critical component of neointima formation after vascular injury. We have previously shown that adventitial myofibroblasts synthesize growth factors that contribute to the formation of neointima after arterial injury. We have also shown that the extracellular matrix protein, TnC, regulates cell migration. Consequently, we investigated the temporospatial expression of TnC by myofibroblasts after vascular injury.

METHODS

In situ hybridization and immunohistochemistry were used to investigate the temporospatial expression of TnC in injured arteries. Northern and Western blots were used to determine the in vitro expression of TnC.

RESULTS

In situ hybridization revealed that the major site of TnC expression early after vascular injury was the adventitial myofibroblasts. Immunohistochemical staining demonstrated that TnC expression began in adventitial myofibroblasts three days after injury. Tenascin-C expression, however, did not persist in this region. Rather, it moved progressively across the vascular wall toward the luminal surface. By one week, TnC expression reached the developing neointima. In vitro, myofibroblasts did not express TnC mRNA under basal conditions. In contrast, angiotensin II and PDGF-BB, factors that have been implicated in remodeling of balloon-injured arteries, markedly upregulated TnC mRNA.

CONCLUSIONS

Tenascin-C is expressed in response to balloon injury. Tenascin-C expression begins with adventitial myofibroblasts. Over a period of 7 to 14 days, expression moves progressively across the vessel wall to the neointima. We hypothesize that adventitial myofibroblasts are actively involved in the formation of neointima and that TnC facilitates migration of these cells during adventitial remodeling.

Corneal macrophage infiltrates following ocular herpes simplex virus type 1 challenge vary in BALB/c mice vaccinated with different vaccines

Macrophage cell infiltrates in the cornea were examined following ocular herpes simplex virus type 1 (HSV-1) challenge of vaccinated BALB/c mice. Mice were vaccinated with individual HSV-1 glycoproteins, cocktails of different HSV-1 glycoproteins, or live avirulent HSV-1 (strain KOS). Cryostat sections of cornea were taken at different times after challenge and reacted with M1/70, F4/80, BM8, or MOMA-1 monoclonal antibodies. The pattern of macrophage responses in the cornea differed depending on the vaccine that was given prior to HSV-1 ocular challenge. No macrophage response was detected in mice vaccinated with the highly protective 5gPs consisting of the five glycoproteins gB, gC, gD, gE, and gI. In contrast, mock vaccinated mice and mice vaccinated with gK, which is known to exacerbate HSV-1 induced eye disease, had high sustained macrophage responses. Mice vaccinated with 7gPs (5gPs+gG and gH) had moderate levels of macrophages. It appeared that (1) the most effective vaccines induced no detectable infiltrating macrophages in the eyes, while the least efficacious vaccines had very high levels of infiltrating macrophages; (2) presence of CD11b(+) cells in the cornea appeared to correlate with enhanced blepharitis, but did not appear to affect corneal scarring; and (3) presence of F4/80(+) cells in the cornea tended to correlate with increased corneal scarring.

Colocalization of tenascin and sympathetic nerves in a canine model of nerve sprouting and sudden cardiac death

INTRODUCTION

Sympathetic nerve sprouting after myocardial infarction (MI) may contribute significantly to the occurrence of ventricular arrhythmia and sudden cardiac death. Tenascin-X (TnX), a matrix protein known to be associated with nerve growth in central and peripheral nerves, also may play a role in cardiac nerve sprouting after MI.

METHODS AND RESULTS

Immunocytochemical staining techniques were used to identify nerves in 5-microm serial sections from 6 normal dogs and 11 dogs with MI. Among the dogs with MI, 4 also received nerve growth factor infusion to the left stellate ganglion. The time between MI to tissue harvest averaged 35.7 +/- 14.4 days. Tyrosine hydroxylase (TH) stain was used to identify sympathetic nerves, and growth-associated protein-43 (GAP-43) was used to identify growing nerves. Polyclonal antibody was obtained for use in identifying TnX. Nerves were evident in both the infarcted and noninfarcted areas. Many nerves were found around blood vessels. A total of 181 nerves in 69 slides were examined: 89 were from noninfarcted myocardium, 4 from infarct, 13 from infarct border zone, and 75 from perivascular regions. Except in normal dogs, all nerves stained positive for TH also stained positive for GAP-43, indicating sympathetic nerve sprouting after MI. In all dogs, the nerves that stained positive for TH also stained positive for TnX.

CONCLUSION

There is a colocalization of TnX, GAP-43, and TH in sprouted cardiac nerves. These results suggest that TnX is important not only in the existing normal myocardial nerve cells but also in cardiac sympathetic nerve sprouting after MI.