Phase I-II Study of Prone Hypofractionated Accelerated Breast and Nodal Intensity Modulated Radiation Therapy

PURPOSE/OBJECTIVE(S)

In patients (pts) with breast cancer, prone radiation therapy (RT) has been shown to reduce heart and lung dose which may decrease late toxicity. Routinely used for whole breast irradiation, its use to treat regional lymph nodes (LNs) is not widespread.

MATERIALS/METHODS

In this phase I-II study, pts treated with partial mastectomy or mastectomy with 1-5 pathologically involved LNs underwent whole breast or post-mastectomy RT plus regional nodal irradiation using IMRT to the supraclavicular and level III axillary LNs. Pts who underwent sentinel LN biopsy (SLNB) alone (no axillary dissection) had the level I and II axillary LNs included in the RT field. 40.5Gy in 15 daily 2.7Gy fractions with daily concomitant 0.5Gy tumor bed boost was prescribed. Normal tissue dose constraints included heart V5Gy<5%, ipsilateral lung V10Gy<20%, contralateral lung V5Gy<15%, ipsilateral brachial plexus (BP) maximal dose (Dmax)<43Gy, spinal cord Dmax≤37.5Gy, spinal cord + 0.5cm Dmax<41Gy, thyroid contralateral lobe Dmax<16Gy, esophagus V30Gy<50% and Dmax≤40.5Gy. The primary endpoints were dosimetric feasibility and incidence of >grade 2 acute toxicity according to CTCAE, v3.0. The secondary endpoint was late toxicity. Exploratory outcomes were local recurrence, disease free survival (DFS), and overall survival (OS).

RESULTS

Between January 2011 to December 2016, 97 pts with stage IB-IIA breast cancer were enrolled. 66 pts underwent partial mastectomy and 31 pts underwent mastectomy. 16 pts had SLNB alone. 33% (95% CI: 23.8%, 43.3%) met all protocol dose constraints. Heart, contralateral lung, spinal cord and esophagus V30Gy constraints were met by all pts. The ipsilateral lung constraint was met in 95% (95% CI: 88.6%, 98.4%) of plans with a mean V10Gy of 9.44% (SD: 6.08). The BP Dmax constraint was exceeded in 31.6% (95% CI: 22.4%, 41.9%) of plans with a mean increase of 2.86 Gy (SD: 7.92 Gy) over target. The esophageal Dmax<40.5Gy constraint was exceeded in 6 plans with an increase in 0.74 Gy (SD: 0.46 Gy) over target. There were no grade 3 acute toxicities meeting the primary toxicity endpoint. Common acute low-grade toxicities by pt included fatigue (grade 1: 54 [56%]; grade 2: 2 [2%]), esophagitis (grade 1: 8 [8%]; grade 2: 2 [2%]), dermatitis (grade 1: 81 [84%]; grade 2: 6 [6%]). At median and maximum follow up of 8.02 (IQR: 3.31) and 13.3 years, respectively, there were 2 local recurrences (2.1%). DFS and OS were 86.6% (95% CI: 78.2%, 92.7%) and 90.7% (95% CI: 83.1%, 95.7%), respectively. The incidence of pts with maximum grade 1, 2 and 3 late toxicities were 39 (40%), 14 (14%), and 2 (2%), respectively. The maximum grade late toxicities included 1 grade 3 retraction and 2 grade 3 asymmetries. There was no brachial plexopathy or pneumonitis.

CONCLUSION

Patients treated with prone hypofractionated hybrid breast/chest wall tangents and IMRT to the regional LNs demonstrate excellent dosimetry to the heart, lungs and spinal cord, minimal acute and late toxicity and excellent clinical outcomes. PMID: 26723552.

A Radiation Therapy Contouring Atlas for Delineation of the Level I-II Axilla in the Prone Position

PURPOSE/OBJECTIVE(S)

When patients are treated prone for whole breast irradiation (WBI), the axilla typically receives less dose than when patients are treated with WBI in the supine position. There are situations, however, where the axilla is a target as in a situation where the physician intends to treat with "high tangents" to provide good coverage of both the breast and level I-II axilla. In these scenarios, ideal target delineation when the patient is in the prone position is not well-defined. While different consensus guidelines exist for delineation of the nodal areas in the supine position, to our knowledge there are no contouring guidelines for the regional nodes in the prone position based on bone, skin, vascular and muscle landmarks.

MATERIALS/METHODS

Forty-three patients treated with high tangents in the prone position from 2012-2018 were identified as representative cases. The level I and II regional nodal contours from the Radiation Therapy Oncology Group (RTOG) breast cancer atlas were adapted for prone position by a radiation oncologist and a breast radiologist based on anatomic considerations and changes observed from supine to prone positioning on diagnostic imaging. The revised nodal contours were reviewed by an expanded expert multidisciplinary panel including additional breast radiation oncologists and surgical oncologists to delineate the level I and II axilla on noncontrast computed tomography (CT) scans.

RESULTS

We adapted the RTOG breast cancer atlas, supported by detailed figures, in order to create a CT based atlas of the level I and II axillary lymph node stations in the prone position. For the level I axilla, the cranial and caudal anatomic boundaries remain unchanged. With transition to the prone position from supine, tenting of the pectoralis major occurs displacing the muscle from the chest wall and shifting the axillary space anteromedial to the lateral border of the pectoralis major. Therefore, the anterior boundary is now defined by the plane of the anterior extent of the pectoralis major to skin. The medial boundary is defined by the plane of the lateral border of the pectoralis major and pectoralis minor including to ribs and intercostal muscles. The lateral boundary is defined by the skin, cropped by 5mm. The posterior boundary is defined by the plane of the anterior surface of the latissimus dorsi and subscapularis muscle to skin. For the level II axilla, the cranial, posterior, medial and lateral boundaries remain unchanged. With transition from supine to prone, the axilla exhibits an anterolateral shift, now laterally abutting the lateral border of the pectoralis minor. The anterior boundary is now defined as the posterior aspect of the pectoralis major muscle. The caudal boundary is where the pectoralis minor inserts into ribs.

CONCLUSION

The adaptations to the RTOG breast cancer atlas for prone positioning will enable radiation oncologists to more accurately target the level I and II axilla when treating patients prone in whom the axilla is a target in addition to the breast.

Effectiveness and Toxicity of Five Fraction Prone Accelerated Partial Breast Irradiation

PURPOSE/OBJECTIVE(S)

Accelerated partial breast irradiation (APBI) after breast conserving therapy (BCT) is increasingly used to treat women with early stage breast cancer. Our institution was an early adopter of 5-fraction ABPI and delivers APBI primarily to patients in the prone position. This study reports long term oncologic and cosmetic outcome in a large cohort of women treated with 5-fraction external beam APBI.

MATERIALS/METHODS

We included patients receiving APBI 600 cGy × 5 fx delivered every other day or every day between 2010 and 2022. Late toxicities and clinician and patient rated cosmesis were evaluated for patients with > 6 month follow up. Univariate and multivariate logistic regression models were used to identify clinical and dosimetric factors associated with development of acute and late toxicities, clinician and patient rated cosmesis. All statistical tests were two-sided, and the null hypothesis was rejected for p<0.05. Kaplan Meier methodology was used to calculate overall survival (OS), disease-free survival (DFS) and locoregional recurrence-free survival (LR-RFS).

RESULTS

Four hundred and forty-two patients received APBI either daily (56%) or every other day (44%). Most of the patients (92%) were treated in the prone position. Average mean heart dose was 23 cGy for left-sided and 11 cGy for right-sided breast cancers. Ipsilateral lung V30% ≤ 30%. At a median follow up of 48 months (range: 5.96 - 155 months), 12 (2.7%) patients developed a local recurrence, 14 (3.2%) patients developed a contralateral breast primary, 10 patients (2.3%) developed a distant metastasis and one patient (0.2%) developed a local recurrence followed by a distant metastasis 1 month later. Out of 258 patients with > 6 month follow up, rates of late grade 1-2 telangiectasia, fibrosis, edema, atrophy and hyperpigmentation were 4%, 18%, 1%, 19% and 7% respectively. There was only one late grade 3 event in a patient who developed significant breast atrophy. The rate of good-excellent physician and patient rated cosmesis was 95% and 89% respectively (N = 256 at median follow up of 80 months). On multivariate logistic regression, patients who did not receive any adjuvant endocrine or chemotherapy were at increased risk of developing a local recurrence. Patients with PR negative disease were at increased risk of distant metastasis. Patient who experienced any grade of acute dermatitis during treatment were at increased risk of any high grade (grade ≥ 2) late adverse event and worse physician rated cosmesis. Daily or every other day treatment did not correlate with worse toxicity or clinical outcomes. Plastic surgery involvement, LVI, EIC, lobular histology, and ER negativity did not correlate with an increased risk of recurrence. Five-year LR-RFS, DFS and OS were 98%, 92.5% and 98.6% respectively.

CONCLUSION

Five- fraction APBI delivered primarily in the prone position either daily or every other day was effective with low rates of local recurrence, minimal toxicity and excellent cosmetic scores at long term follow up.

Comparing Changes in Medicare Reimbursement for Radiation Oncology and Medical Oncology (2010-2020)

PURPOSE/OBJECTIVE(S)

A recent study found that radiation oncology (RO) has seen significant declines in Medicare reimbursement (MCR) from 2010-2019. While it is presumed that other cancer subspecialties have seen decreasing MCR, to our knowledge, there are no studies directly comparing changes in MCR between RO and other oncology subspecialties. In this study, we analyze changes in MCR from 2010-2020 for both RO and medical oncology. We hypothesized that the declines in MCR will be similar between the two fields.

MATERIALS/METHODS

The publicly available Physician/Supplier Procedure Summary (PSPS) database was used for all years from 2010-2020. All reimbursement for providers with primary provider codes 92 (RO) and 83 and 90 (heme/onc and medical oncology, respectively) were analyzed. For the 150 most highly-reimbursed HCPCS codes for each specialty in 2010, the total allowed charge for each code was corrected for inflation and then divided by the number of submitted claims to calculate average MCR per code for each year. For each code and each specialty, the 2020 billing frequency was multiplied by the calculated average reimbursement per claim in a given year to calculate what the reimbursement would have been in that year using 2020 dollars and utilization rates (projected reimbursement). The projected reimbursement was summed for all HCPCS codes in each year for each specialty to calculate an aggregate MCR for that specialty for that year. This aggregate MCR was then compared with the actual 2020 reimbursement for that basket of codes to calculate the change in MCR over time.

RESULTS

Both medical and radiation oncology saw decreases in projected vs. actual MCR from 2010-2020 for this basket of services (Table). Adjusting for inflation and utilization, RO MCR declined by $0.7 billion (B) (-29.0%) from 2010 to 2020 and by $0.2B (-10.5%) from 2015 to 2020 while medical oncology MCR declined by $0.8B (-14.7%) from 2010-2020 and by $0.4B (-6.6%) from 2015-2020. The average decrease per year in projected vs. actual reimbursement for RO was 2.9% (2010 to 2015) and 1.05% (2015 to 2020) and for medical oncology was 1.5% (2010-2015) and 0.7% (2015-2020), respectively.

CONCLUSION

Adjusting for inflation, Medicare reimbursement for a large array of services has declined for both medical oncology and RO from 2010 - 2020. Contrary to our hypothesis, RO reported a 97% greater relative decline in reimbursement compared with medical oncology from 2010 - 2020. Significant decreases in reimbursement to both fields and their potential implications on patient care and access to care should be considered by policymakers while shifting towards an episode-based Alternative Payment Model and when considering further cuts to Medicare reimbursement.

Characterization of Objective Skin Color Changes during and after Breast and Chest Wall Radiotherapy and Correlation with Radiation-Induced Skin Toxicity in Breast Cancer Patients, Including Patients with Skin of Color

PURPOSE/OBJECTIVE(S)

Radiation dermatitis (RD) is common among women undergoing breast and chest wall radiotherapy (RT); however, existing scales to assess the severity of RD are subjective and do not account for variability in skin of color (SOC). For instance, the Common Terminology Criteria for Adverse Events (CTCAE) criteria do not include hyperpigmentation in the grading scale. There is data indicating worse RD in African American and Hispanic patients; however, the rate and severity in SOC remains unknown given the lack of data using objective measures of RD. Spectrophotometry is one method to quantify the appearance of color by measuring spectral characteristics without the bias associated with subjective clinical scoring. We present a phase I prospective non-therapeutic clinical trial to objectively define SOC at baseline and evaluate spectrophotometric skin changes during and after breast or chest wall RT in parallel with physician-graded RD using CTCAE criteria. We hypothesize that there will be greater discrepancy between physician graded RD and objective measures of RD in patients with SOC in whom hyperpigmentation will be undercaptured by physician-grading. This is the first study intending to correlate SOC with objective changes after RT as a reliable indicator of RD. We offer a novel system for evaluating RD that is applicable to SOC.

MATERIALS/METHODS

A total of 60 patients with localized breast cancer (stage 0-III) undergoing conventional whole breast or chest wall RT (50Gy/ 25 fx), hypofractionated whole breast RT (40.5Gy/15 fx) or ultrahypofractionated partial breast RT (6Gy x5), with or without regional nodal RT were enrolled. 3 skin color readouts using the Commission International de l'Eclairage 3D color system (l*, a*, b*) were measured within the radiation field using a spectrophotometer at baseline, once weekly during RT, 10 days post RT, 4 weeks and 12 months post RT. The spectrophotometer is a non-invasive, hand-held device that is used in the clinic room with no additional equipment or setup requirements. Data is automatically exported to a spreadsheet organized by timepoint and patient. The l* axis is a gray scale (0 = black, 100 = white) correlating with skin pigmentation and the a* axis describes red and green values correlating with erythema. The primary objective is to evaluate the changes from baseline in skin color readouts in the quadrant of tumor location during and after RT based on fractionation. The secondary objective is to evaluate changes within and across groups defined by baseline skin color. Exploratory objectives include evaluating the association of baseline color readouts and changes after RT with acute and late grade > 2 clinician-rated skin and subcutaneous tissue effects according to the CTCAE, v5.0, physician graded cosmesis and clinical interventions to treat RD, such as use of topical steroids and oral analgesics. As of January 2023, we have enrolled 100% of the planned patients.

RESULTS

To be determined.

CONCLUSION

To be determined. Clinical Study Identifier: S22-00192.

A Phase II, Randomized, Double Blind, Placebo Controlled Study of the Safety and Efficacy of a Caffeine-Based Antifibrosis Cream in Patients with Breast Cancer Undergoing Radiation Therapy

PURPOSE/OBJECTIVE(S)

Radiation induced fibrosis (RIF) is a common long term adverse event in patients undergoing post-mastectomy radiation therapy (PMRT) which can cause capsular contracture, implant loss, and reconstruction complications in women with implant-based breast reconstruction. At a molecular level, adenosine is a driver of RIF. Preclinical data have shown that pharmacologic blockade of the adenosine A2A Receptor (A2AR) in mice as well as an A2AR knockout mouse model prevented skin fibrosis associated with radiation injury. Caffeine is an A2AR antagonist which has been shown to block the development of hepatic fibrosis in liver disease patients. We present a phase II placebo controlled clinical trial to evaluate whether a caffeine-based cream can prevent RIF and thus reduce the rates of reconstructive complications in patients with tissue expander-based reconstruction requiring PMRT.

MATERIALS/METHODS

Women ≥ 18 years old with breast carcinoma stage 0-III status post mastectomy with tissue expander-based reconstruction who require PMRT to the chest wall +/- the regional nodes are being enrolled. The target accrual is 60 patients. Boost field to the chest wall, scar and/or nodal region is allowed. Patients with inflammatory breast cancer or those requiring skin bolus are excluded. Prior to starting radiation, patients will be randomized to placebo vs. caffeine cream and they will be instructed to apply the cream twice a day starting on the first day of radiation treatment and continuing daily for the duration of radiation until the removal of tissue expanders. The primary study endpoint is reconstructive complications requiring rehospitalization or reoperation by 2 years post radiation including reconstructive failure with or without reconstruction. A safety endpoint of grade ≥ 2 acute radiation dermatitis will also serve as a co-primary endpoint. Secondary endpoints are wound infection/cellulitis, hematoma, seroma, threatened exposure, wound dehiscence, implant leakage, rupture, and or deflation, and capsular contracture that do not meet criteria for the primary endpoint. Clinician rated cosmesis, local recurrence, regional recurrence, distant metastasis and survival up to 4 years are additional secondary endpoints. Exploratory endpoint includes the use of shear wave elastography (SWE) as a potential tool to quantitatively measure post irradiation fibrosis. Correlative aims include assessing epidermal thickness and fat layer thickness from tissue obtained at time of implant exchange for association with the development of fibrosis. The primary efficacy endpoint will be estimated using Kaplan Meier methods from date of randomization. Treatment comparisons will be based on a 2-sided log rank chi-square test and the hazard ratio will be estimated with 95% confidence intervals. The study started accruing in 12/2019 and is estimated to end by 04/2024. As of January 2023, 67% (40/60 patients) of the planned patients have been enrolled.

RESULTS

To be determined.

CONCLUSION

To be determined.

Olfactory conditioned same-sex partner preference in female rats: Role of ovarian hormones

The dopamine D2-type receptor agonist quinpirole (QNP) facilitates the development of conditioned same-sex partner preference in males during cohabitation, but not in ovariectomized (OVX) females, primed with estradiol benzoate (EB) and progesterone (P). Herein we tested the effects of QNP on OVX, EB-only primed females. Females received a systemic injection (every four days) of either saline (Saline-conditioned) or QNP (QNP-conditioned) and then cohabited for 24h with lemon-scented stimulus females (CS+), during three trials. In test 1 (female-female) preference was QNP-free, and females chose between the CS+ female and a novel female. In test 2 (male-female) they chose between the CS+ female and a sexually experienced male. In test 1 Saline-conditioned females displayed more hops & darts towards the novel female, but QNP-conditioned females displayed more sexual solicitations towards the CS+ female. In test 2 Saline-conditioned females displayed a clear preference for the male, whereas QNP-conditioned females displayed what we considered a bisexual preference. We discuss the effect of dopamine and ovarian hormones on the development of olfactory conditioned same-sex preference in females.

Pharmacological and clinical profile of lenvatinib (E-7080) in the treatment of advanced, radioiodine-refractory, differentiated thyroid cancer

After the pathogenesis of thyroid carcinomas was better understood and the role of molecular alterations in RET, BRAF and RET/PTC rearrangement was revealed, several trials using multikinase inhibitors were developed during the last decade for the treatment of recurrent radioactive iodine (RAI)-refractory differentiated thyroid cancer (DTC), achieving a remarkable success. Sorafenib became the first drug approved for this indication in more than two decades after a significant improvement in the progression-free survival was demonstrated. Lenvatinib (E-7080), an orally active inhibitor of multiple receptor tyrosine kinases including vascular endothelial growth factor receptors (VEGFR) 1, 2 and 3, proto-oncogene tyrosine-protein kinase receptor Ret and mast/stem cell growth factor receptor Kit, yielded highly promising early clinical data, even when given after progression on first-line therapy. The phase III SELECT trial recently demonstrated the impressive clinical activity of the drug in RAI-refractory thyroid cancer, leading to the drug's approval by the regulatory agencies and potentially making lenvatinib the most effective drug available to date for the treatment of the disease.

A balanced sleep/wakefulness classification method based on actigraphic data in adolescents

Several research groups have developed automated sleep-wakefulness classifiers for night wrist actigraphic (ACT) data. These classifiers tend to be unbalanced, with a tendency to overestimate the detection of sleep, at the expense of poorer detection of wakefulness. The reason for this is that the measure of success in previous works was the maximization of the overall accuracy, disregarding the balance between sensitivity and specificity. The databases were usually sleep recordings, hence the over-representation of sleep samples. In this work an Artificial Neural Network (ANN), sleep-wakefulness classifier is presented. ACT data was collected every minute. An 11-min moving window was used as observing frame for data analysis, as applied in previous sleep ACT studies. However, our feature set adds new variables such as the time of the day, the median and the median absolute deviation. Sleep and Wakefulness data were balanced to improve the system training. A comparison with previous studies can still be done, by choosing the point in the ROC curve associated with the corresponding data balance. Our results are compared with a polysomnogram-based hypnogram as golden standard, rendering an accuracy of 92.8%, a sensitivity of 97.6% and a specificity of 73.4%. Geometric mean between sensitivity and specificity is 84.9%.

Single trial P300 detection in children using expert knowledge and SOM

Preliminary results of an automatic system for single trial P300 visual evoked potential events detection are presented. For each single trial P300, several candidate events were generated, and then filtered, using 3 wave features. The surviving candidate events were fed into a SOM-based classifier. A context filter was applied before the final output. No stationary condition of the P300 is involved in the algorithms. Recordings of 27 assessment sessions, each with 120 trials, were visually inspected by experts to identify and mark the P300 events, which was accomplished in about one third of the trials. The dataset was divided in training (18) and testing (9) subsets. The system identifies the initial and end times of the P300; it obtained a sensitivity of 53.9%, a specificity of 64.0% and an accuracy of 61.2% in the testing dataset.

P5-14-13: Favorable Prognosis in Patients with T1a,b Node-Negative Triple Negative Breast Cancers Treated with Multimodality Therapy

Purpose: To evaluate the clinical characteristics, natural history and outcomes in patients with ≤1cm, node-negative triple negative breast cancer (TNBC).

Materials and Methods: After excluding patients who received neoadjuvant therapy, 1,022 TNBC patients who received definitive breast surgery from 1999 to 2006 were identified from an institutional database. Among these, 194 patients had node-negative tumors ≤1cm and comprise the study population. Clinical data was abstracted and survival outcomes were analyzed.

Results: Median follow-up time was 71 months (range 2–143). Median age at diagnosis was 55.5 years (range 27–84). T stage was T1mic in 16 (8.2%), T1a in 49 (25.3%), T1b in 129 (66.5%). The majority of tumors were poorly differentiated (N= 142, 73%), lacked lymphovascular invasion (N= 170, 87.6%) and were screening-detected (69%, N=134). Breast-conserving surgery (BCS) was employed in 129 (66.5%) and mastectomy in 65 (33.5%) patients. 113 (58%) patients received adjuvant chemotherapy and 123 (63%) received whole breast radiation. Patients who received chemotherapy tended to have more adverse clinical and disease features (younger age,T1b, poor tumor grade; all p&lt;0.05). For the entire group, 5 year local recurrence-free survival was 96% and distant metastasis-free survival was 95%, with no difference in distant relapse rates between T1mic/T1a vs. T1b patients (94.5% vs 95.5%, p=0.81 )or by receipt of chemotherapy (95.9% vs 94.5%, p=0.63).

Conclusion: Excellent 5-year locoregional and distant control rates were achievable in patients with TNBC tumors ≤ 1.0 cm, 58% of whom received chemotherapy. These results identify a group of TNBC patients with favorable outcomes following early detection and multimodality treatment.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-14-13.

The mTOR signaling network: insights from its role during embryonic development

Target of Rapamycin (TOR) signaling, originally discovered as the pathway affected by an antifungal macrolide, exemplifies the potential of medicinal chemistry as a discovery tool. Three decades from its identification, signaling involving the TOR kinase has evolved into a complex network with a crucial role in vertebrate growth control. Specifically, it integrates signals to coordinate cell growth (i.e., enhanced mass and size) and cell cycle progression with sufficiency of nutrients, energy, and growth factors. In this review, we discuss multiple aspects of TOR signaling, including cellular regulators and mediators, human diseases related to TOR dysregulation such as cancer, and signaling nodes in the pathway amenable to targeted drug inhibition. The functions and mechanisms of TOR during embryonic development highlight the dynamic role of TOR signaling and reveal additional functions beyond cell growth control. Embryonic TOR signaling has differential tissue-specific and temporal effects, and is involved in organogenesis, sexual differentiation, and epithelial-to-mesenchymal transition signaling. Molecular mechanisms that may contribute to embryonic-specific TOR functions are also examined here. Finally, this review discusses the complex signaling of mTOR in cancer and the development of mTOR inhibitors for cancer therapy.

p63 consensus DNA-binding site: identification, analysis and application into a p63MH algorithm

p53 and p63 belong to a family of sequence-specific transcription factors regulating key cellular processes. Differential composition of the p53 and p63 DNA-binding sites may contribute to distinct functions of these protein homologues. We used SELEX (systematic evolution of ligands by exponential enrichment) methodology to identify nucleic acid ligands for p63. We found that p63 bound preferentially to DNA fragments conforming to the 20 bp sequence 5'-RRRC(A/G)(A/T)GYYYRRRC(A/T)(C/T)GYYY-3'. Relative to the p53 consensus, the p63 consensus DNA-binding site (DBS) was more degenerate, particularly at positions 10 and 11, and was enriched for A/G at position 5 and C/T at position 16 of the consensus. The differences in DNA-binding site preferences between p63 and p53 influenced their ability to activate transcription from select response elements (REs) in cells. A computer algorithm, p63MH, was developed to find candidate p63-binding motifs on input sequences. We identified genes responsive to p63 regulation that contain functional p63 REs. Our results suggest that the sequence composition of REs could be one contributing factor to target gene discrimination between p63 and p53.

Rotavirus vp7 antigen produced by Lactococcus lactis induces neutralizing antibodies in mice

AIMS

To determine if live recombinant Lactococcus lactis strains expressing rotavirus VP7 antigen are immunogenic in mice.

METHODS AND RESULTS

Using the food-grade lactic acid bacterium L. lactis as a carrier, we expressed VP7, the major rotavirus outer shell protein and one of the main components of the infective particle, as a cytoplasmic, secreted or cell wall anchored forms. Our results showed that recombinant L. lactis strains secreting VP7 proved to be more immunogenic than strains containing the antigen in the cytoplasm or anchored to the cell wall.

CONCLUSIONS

This is the first demonstration that recombinant L. lactis producing VP7 can induce the production of a neutralizing antibody response against rotavirus by the intragastric route.

SIGNIFICANCE AND IMPACT OF THE STUDY

Rotaviruses are the single most important aetiological agents of severe diarrhoea of infants and young children worldwide and have been estimated to be responsible for 650 000-800 000 deaths per year of children younger than 5 years old in development countries. Thus, the development of a safe and effective vaccine has been a global public health goal. Although two of five mice orally inoculated with L. lactis strains secreting VP7 elicited a specific-antibody response, these strains could be very useful to be used as a prototype to develop a new generation of protective rotavirus vaccines.

Power requirements for vibrotactile piezo-electric and electromechanical transducers

Human-machine information transfer through tactile excitation has addressed new applications in virtual reality, robotics, telesurgery, sensory substitution and rehabilitation for the handicapped in the past few years. Power consumption is an important factor in the design of vibrotactile displays, because it affects energy needs and the size, weight, heat dissipation and cost of the associated electronics. An experimental study is presented on the power required to reach tactile thresholds in electromechanical and piezo-electric transducers. Three different waveforms are considered, with an excitatory period formed by a burst of rectangular 50% duty cycle pulses (R50), rectangular low duty cycle pulses (RLO) and sinusoidal pulses (SIN). Ten different pulse repetition periods (RPs) were considered in the range 1/550-1/25 s. The voltage and current waveforms applied to the transducers at sensation thresholds in a group of 12 healthy subjects were sampled and stored in a digital oscilloscope. The average power was determined for each subject, and differences of two orders of magnitude were measured between the electromechanical and the piezo-electric transducer power consumption. Results show that, for the electromechanical transducer, a smaller power consumption of 25 microW was determined for RP = 1/25 s and the RLO waveform. In the case of the piezo-electric transducer, power of 0.21 microW was determined for SIN excitation and RP = 1/250 s. These results show the advantages of reducing power requirements for vibrotactile displays, which can be optimised by the choice of appropriate types of transducer, excitatory waveforms and pulse repetition periods.

Polysomnographic pattern recognition for automated classification of sleep-waking states in infants

A robust, automated pattern recognition system for polysomnography data targeted to the sleep-waking state and stage identification is presented. Five patterns were searched for: slow-delta and theta wave predominance in the background electro-encephalogram (EEG) activity; presence of sleep spindles in the EEG; presence of rapid eye movements in an electro-oculogram; and presence of muscle tone in an electromyogram. The performance of the automated system was measured indirectly by evaluating sleep staging, based on the experts' accepted methodology, to relate the detected patterns in infants over four months of post-term age. The set of sleep-waking classes included wakefulness, REM sleep and non-REM sleep stages I, II, and III-IV. Several noise and artifact rejection methods were implemented, including filters, fuzzy quality indices, windows of variable sizes and detectors of limb movements and wakefulness. Eleven polysomnographic recordings of healthy infants were studied. The ages of the subjects ranged from 6 to 13 months old. Six recordings counting 2665 epochs were included in the training set. Results on a test set (2,369 epochs from five recordings) show an overall agreement of 87.7% (kappa 0.840) between the automated system and the human expert. These results show significant improvements compared with previous work.

Intensity-modulated radiation therapy reduces late salivary toxicity without compromising tumor control in patients with oropharyngeal carcinoma: a comparison with conventional techniques

BACKGROUND AND PURPOSE

Intensity-modulated radiation therapy (IMRT) offers superior dosimetric conformity for normal tissue sparing in patients with oropharyngeal cancer. In this study, acute and late toxicity, and tumor control were compared between conventional beam arrangement (CRT) and IMRT.

MATERIALS AND METHODS

Between January 1970 and December 1999, 430 patients with carcinoma of the oropharynx were treated at the Mallinckrodt Institute of Radiology. There were 260 patients with tonsil primary tumors and 170 patients with tumors arising from the base of the tongue. Twenty-four (6%) patients had stage I disease, 88 (20%) had stage II, 128 (30%) had stage III, and 190 (44%) had stage IV disease. Patients were divided into five treatment groups. Group I consisted of 109 patients who received preoperative CRT. Group II consisted of 142 patients who received postoperative CRT. Group III consisted of 153 patients who received definitive CRT. Inverse planning IMRT (Peacock, NOMOS) was used to treat 14 patients postoperatively (Group IV) and 12 patients definitively without surgery (Group V). Acute and late normal tissue side-effects were scored according to the Radiation Therapy Oncology Group radiation morbidity criteria. The median follow-up was 3.9 years.

RESULTS

The 2-year local-regional control values for the five studied groups were 78, 76, 68, 100 and 88%, respectively. The 2-year disease-free survival values for the five studied groups were 68, 74, 58, 92 and 80%, respectively. IMRT significantly reduced the incidence of late xerostomia.

CONCLUSIONS

When IMRT was compared with conventional techniques, the dosimetric advantage of IMRT did translate into a significant reduction of late salivary toxicity in patients with oropharyngeal carcinoma. No adverse impact on tumor control and disease-free survival was observed in patients treated with IMRT.

Radiotherapy for epithelial skin cancer

PURPOSE

To retrospectively review patterns of failure, cosmesis, and outcomes according to treatment modality of patients with histologically confirmed epithelial skin cancer.

METHODS AND MATERIALS

The records of 468 patients having 531 lesions were analyzed; 389 basal cell carcinomas and 142 squamous cell carcinomas were treated, 167 of which were recurrent tumors. Median follow-up was 5.8 years. Electron beam irradiation was used in 19%, superficial x-rays in 60%, a combination of electron beam and superficial x-rays in 20%, and megavoltage photons in <2%.

RESULTS

The overall local tumor control rate was 89%; it was 93% for previously untreated lesions and 80% for recurrent lesions. Patients with basal cell carcinoma had a 92% overall control rate; patients with squamous cell carcinoma 80%. Multivariate analysis showed that local failure was related to the daily dose fractionation. The maximal diameter of the lesion and pathologic tumor type were also significant (p 0.01). Treatment type, patient age, and treatment duration were not significant. Overall, 92% of the treated population with cosmesis data had excellent or good results. The overall complication rate was 5.8%, consisting primarily of soft-tissue necrosis.

CONCLUSIONS

Radiotherapy remains an excellent treatment modality for epithelial skin cancer. Local tumor control, cosmesis, and complications are related to the size of the primary lesion. Recurrent lesions fared worse, and therefore treatment at the earliest possible stage is strongly recommended.

Growth-rate regulation of the Bacillus subtilis accBC operon encoding subunits of acetyl-CoA carboxylase, the first enzyme of fatty acid synthesis

Acetyl-CoA carboxylase catalyses the synthesis of malonyl-CoA, the first intermediate in fatty acid (hence phospholipid) synthesis. The accBC operon from Bacillus subtilis codes for two subunits of acetyl-CoA carboxylase, biotin carboxyl-carrier and biotin carboxylase. In this work, the 5'-end of the accBC mRNA was determined by primer-extension, and transcriptional fusion analysis of the accBC promoter was carried out under a variety of growth conditions. A direct correlation between the levels of transcription of the accBC genes and the rate of cellular growth is reported. Consistent results were also obtained in nutritional upshift and downshift experiments.

Delayed regional metastases, distant metastases, and second primary malignancies in squamous cell carcinomas of the larynx and hypopharynx

OBJECTIVE

To determine the impact of delayed regional metastases, distant metastases, and second primary tumors on the therapeutic outcomes in squamous cell carcinomas of the larynx and hypopharynx.

STUDY DESIGN

Chart review and statistical analysis.

METHODS

A retrospective tumor registry analysis was made of patients with squamous cell carcinomas of the larynx and hypopharynx who were treated with curative intent in the Department of Otolaryngology-Head and Neck Surgery and the Radiation Oncology Center of the Washington University School of Medicine (St. Louis, MO) between January 1971 and December 1991 and developed delayed regional metastases (2 y after treatment), distant metastases, and second primary malignancies.

RESULTS

In 2550 patients, the mean age (59.8 y), sex (8.5 male patients and 1 female patient), and tumor differentiation did not affect the incidence of delayed distant, regional, or second primary malignancies. The overall incidence of delayed regional metastases was 12.4% (317/2550 patients); distant metastases, 8.5% (217/2550); and second primary tumors, 8.9% (228/2550), with a 5-year disease-specific survival of 41%, 6.4%, and 35%, respectively. Second primary malignancies were not statistically related to the origin of the primary tumor, tumor staging, or delayed regional and distant metastases (P =.98). Delayed regional metastases and distant metastases were related to advanced primary disease (T4 stage), lymph node metastases (node positive [N+]), tumor location (hypopharynx), and locoregional tumor recurrence (P < or =.028). Advanced regional metastases at initial diagnosis (N2 and N3 disease) increased the incidence of delayed and distant metastases threefold (P =.017). These two metastatic parameters were significantly greater in hypopharyngeal tumors than in laryngeal tumors (P =.037). The incidences of delayed regional metastases by anatomical location of the primary tumor were as follows: glottic, 4.4%; supraglottic, 16%; subglottic, 11.5%; aryepiglottic fold, 21.9%; pyriform sinus, 31.1%; and posterior hypopharyngeal wall, 18.5%. The incidences of distant metastases were as follows: glottic, 4%; supraglottic, 3.7%; subglottic, 14%; aryepiglottic fold, 16%; pyriform fossa, 17.2%; and posterior hypopharyngeal wall, 17.6%. Seventeen hypopharyngeal tumors (2%) presented with M1 disease. Delayed regional metastases to the ipsilateral treated neck had a significantly worse survival prognosis than delayed metastases to the contralateral nontreated neck (P =.001).

CONCLUSIONS

Conclusions are as follows: 1) The incidence of second primary tumors is independent from the primary tumor staging and distant and delayed regional metastases. The highest incidence occurred in patient groups with the highest disease-free survival rates (P =.0378). 2) Highest incidence of delayed and distant metastases occurred in hypopharyngeal tumors and was three times greater than in laryngeal cancers (P =.028). 3) Salvage therapeutic rates were poor for delayed metastases to the ipsilateral treated nodes and distant metastases as compared with contralateral neck metastases and second primary tumors (P =.001). 4) Delayed and distant lymph node metastases were significantly higher in advanced primary disease (T4 stage), locoregional recurrences, and regional disease (N2 and N3) (P =.028) in both the larynx and hypopharynx. 5) The higher incidence of delayed and distant metastatic disease was related to more advanced initial tumor presentation in hypopharyngeal cancer as compared with laryngeal cancer (P =.039). 6) Incidence of distant metastases was greatest between 1.5 and 6 years after initial treatment with a mean incidence being less than or equal to 3.2 years.

Chemical disease-free survival in localized carcinoma of prostate treated with external beam irradiation: comparison of American Society of Therapeutic Radiology and Oncology Consensus or 1 ng/mL as endpoint

PURPOSE

To compare postirradiation biochemical disease-free survival using the American Society of Therapeutic Radiology and Oncology (ASTRO) Consensus or elevation of postirradiation prostate-specific antigen (PSA) level beyond 1 ng/mL as an endpoint and correlate chemical failure with subsequent appearance of clinically detected local recurrence or distant metastasis.

METHODS AND MATERIALS

Records of 466 patients with histologically confirmed adenocarcinoma of the prostate treated with irradiation alone between January 1987 and December 1995 were analyzed; 339 patients were treated with bilateral 120 degrees arc rotation and, starting in 1992, 117 with three-dimensional conformal irradiation. Doses were 68--77 Gy in 1.8 to 2 Gy daily fractions. Minimum follow-up is 4 years (mean, 5.5 years; maximum, 9.6 years). A chemical failure was recorded using the ASTRO Consensus or when postirradiation PSA level exceeded 1 ng/mL at any time. Clinical failures were determined by rectal examination, radiographic studies, and, when clinically indicated, biopsy.

RESULTS

Six-year chemical disease-free survival rates using the ASTRO Consensus according to pretreatment PSA level for T1 tumors were: < or = 4 ng/mL, 100%; 4.1--20 ng/mL, 80%; and > 20 ng/mL, 50%. For T2 tumors the rates were: < or = 4 ng/mL, 91%; 4.1--10 ng/mL, 81%; 10.1--20 ng/mL, 55%; 20.1--40 ng/mL, 63%; and > 40 ng/mL, 46%. When postirradiation PSA levels higher than 1 ng/mL were used, the corresponding 6-year chemical disease-free survival rates for T1 tumors were 92% for pretreatment PSA levels of < or = 4 ng/mL, 58--60% for levels of 4.1--20 ng/mL, and 30% for levels > 20 ng/mL. For T2 tumors, the 6-year chemical disease-free survival rates were 78% in patients with pretreatment PSA levels of 4--10 ng/mL, 45% for 10.1--40 ng/mL, and 25% for > 40 ng/mL. Of 167 patients with T1 tumors, 30 (18%) developed a chemical failure, 97% within 5 years from completion of radiation therapy; no patient has developed a local recurrence or distant metastasis. In patients with T2 tumors, overall 45 of 236 (19%) had chemical failure, 94% within 5 years of completion of radiation therapy; 4% have developed a local recurrence, and 10%, distant metastasis. In patients with T3 tumors, overall, 24 of 65 (37%) developed a chemical failure, 100% within 3.5 years from completion of radiation therapy; 4% of these patients developed a local recurrence within 2 years, and 12% developed distant metastasis within 4 years of completion of irradiation. The average time to clinical appearance of local recurrence or distant metastasis after a chemical failure was detected was 5 years and 3 years, respectively.

CONCLUSION

There was a close correlation between the postirradiation nadir PSA and subsequent development of a chemical failure. Except for patients with T1 tumors and pretreatment PSA of 4.1--20 ng/mL, there is good agreement in 6-year chemical disease-free survival using the ASTRO Consensus or PSA elevations above 1 ng/mL as an endpoint. Although the ASTRO Consensus tends to give a higher percentage of chemical disease-free survival in most groups, the differences with longer follow-up are not statistically significant (p > 0.05). It is important to follow these patients for at least 10 years to better assess the significance of and the relationship between chemical and clinical failures.

A prospective study of salivary function sparing in patients with head-and-neck cancers receiving intensity-modulated or three-dimensional radiation therapy: initial results

OBJECTIVES

In a prospective clinical study, we tested the hypothesis that sparing the parotid glands may result in significant objective and subjective improvement of xerostomia in patients with head-and-neck cancers. The functional outcome 6 months after the completion of radiation therapy is presented.

METHODS AND MATERIALS

From February 1997 to February 1999, 41 patients with head-and-neck cancers were enrolled in a prospective salivary function study. Inverse-planning intensity-modulated radiation therapy (IMRT) was used to treat 27 patients, and forward-planning three-dimensional radiation therapy in 14. To avoid potential bias in data interpretation, only patients whose submandibular glands received greater than 50 Gy were eligible. Attempts were made to spare the superficial lobe of the parotid glands to avoid underdosing tumor targets in the parapharyngeal space; however, the entire parotid volume was used to compute dose-volume histograms (DVHs) for this analysis. DVHs were computed for each gland separately. Parotid function was assessed objectively by measuring stimulated and unstimulated saliva flow before and 6 months after the completion of radiation therapy. Measurements were converted to flow rate (mL/min) and normalized relative to that before treatment. The corresponding quality-of-life (QOL) outcome was assessed by five questions regarding the patient's oral discomfort and eating/speaking problems.

RESULTS

We observed a correlation between parotid mean dose and the fractional reduction of stimulated saliva output at 6 months after the completion of radiation therapy. We further examined whether the functional outcome could be modeled as a function of dose. Two models were found to describe the dose-response data well. The first model assumed that each parotid gland is comprised of multiple independent parallel functional subunits (corresponding to computed tomography voxels) and that each gland contributes equally to overall flow, and that saliva output decreases exponentially as a quadratic function of irradiation dose to each voxel. The second approach uses the equivalent uniform dose (EUD) metrics, which assumes loss of salivary function with increase in EUD for each parotid gland independently. The analysis suggested that the mean dose to each parotid gland is a reasonable indicator for the functional outcome of each gland. The corresponding exponential coefficient was 0.0428/Gy (95% confidence interval: 0.01, 0.09). The QOL questions on eating/speaking function were significantly correlated with stimulated and unstimulated saliva flow at 6 months. In a multivariate analysis, a toxicity score derived from the model based on radiation dose to the parotid gland was found to be the sole significant predictive factor for xerostomia. Neither radiation technique (IMRT vs. non-IMRT) nor chemotherapy (yes or no) independently influenced the functional outcome of the salivary glands.

CONCLUSION

Sparing of the parotid glands translates into objective and subjective improvement of both xerostomia and QOL scores in patients with head-and-neck cancers receiving radiation therapy. Modeling results suggest an exponential relationship between saliva flow reduction and mean parotid dose for each gland. We found that the stimulated saliva flow at 6 months after treatment is reduced exponentially, for each gland independently, at a rate of approximately 4% per Gy of mean parotid dose.

A novel approach to overcome hypoxic tumor resistance: Cu-ATSM-guided intensity-modulated radiation therapy

PURPOSE

Locoregional tumor control for locally advanced cancers with radiation therapy has been unsatisfactory. This is in part associated with the phenomenon of tumor hypoxia. Assessing hypoxia in human tumors has been difficult due to the lack of clinically noninvasive and reproducible methods. A recently developed positron emission tomography (PET) imaging-based hypoxia measurement technique which employs a Cu(II)-diacetyl-bis(N(4)-methylthiosemicarbazone) (Cu-ATSM) tracer is of great interest. Oxygen electrode measurements in animal experiments have demonstrated a strong correlation between low tumor pO(2) and excess (60)Cu-ATSM accumulation. Intensity-modulated radiation therapy (IMRT) allows selective targeting of tumor and sparing of normal tissues. In this study, we examined the feasibility of combining these novel technologies to develop hypoxia imaging (Cu-ATSM)-guided IMRT, which may potentially deliver higher dose of radiation to the hypoxic tumor subvolume to overcome inherent hypoxia-induced radioresistance without compromising normal tissue sparing.

METHODS AND MATERIALS

A custom-designed anthropomorphic head phantom containing computed tomography (CT) and positron emitting tomography (PET) visible targets consisting of plastic balls and rods distributed throughout the "cranium" was fabricated to assess the spatial accuracy of target volume mapping after multimodality image coregistration. For head-and-neck cancer patients, a CT and PET imaging fiducial marker coregistration system was integrated into the thermoplastic immobilization head mask with four CT and PET compatible markers to assist image fusion on a Voxel-Q treatment-planning computer. This system was implemented on head-and-neck cancer patients, and the gross tumor volume (GTV) was delineated based on physical and radiologic findings. Within GTV, regions with a (60)Cu-ATSM uptake twice that of contralateral normal neck muscle were operationally designated as ATSM-avid or hypoxic tumor volume (hGTV) for this feasibility study. These target volumes along with other normal organs contours were defined and transferred to an inverse planning computer (Corvus, NOMOS) to create a hypoxia imaging-guided IMRT treatment plan.

RESULTS

A study of the accuracy of target volume mapping showed that the spatial fidelity and imaging distortion after CT and PET image coregistration and fusion were within 2 mm in phantom study. Using fiducial markers to assist CT/PET imaging fusion in patients with carcinoma of the head-and-neck area, a heterogeneous distribution of (60)Cu-ATSM within the GTV illustrated the success of (60)Cu-ATSM PET to select an ATSM-avid or hypoxic tumor subvolume (hGTV). We further demonstrated the feasibility of Cu-ATSM-guided IMRT by showing an example in which radiation dose to the hGTV could be escalated without compromising normal tissue (parotid glands and spinal cord) sparing. The plan delivers 80 Gy in 35 fractions to the ATSM-avid tumor subvolume and the GTV simultaneously receives 70 Gy in 35 fractions while more than one-half of the parotid glands are spared to less than 30 Gy.

CONCLUSION

We demonstrated the feasibility of a novel Cu-ATSM-guided IMRT approach through coregistering hypoxia (60)Cu-ATSM PET to the corresponding CT images for IMRT planning. Future investigation is needed to establish a clinical-pathologic correlation between (60)Cu-ATSM retention and radiation curability, to understand tumor re-oxygenation kinetics, and tumor target uncertainty during a course of radiation therapy before implementing this therapeutic approach to patients with locally advanced tumor.

Radiation therapy for carcinoma of the cervix with biopsy-proven positive para-aortic lymph nodes

PURPOSE

To evaluate local tumor control, cause-specific survival, patterns of relapse, and toxicity in patients with cervical cancer and positive para-aortic lymph nodes treated with radiation therapy alone.

METHODS

This is a retrospective chart review of 43 patients with cervical cancer and biopsy-proven positive para-aortic lymph nodes treated with radiation therapy treated from 1965 to 1993. There were 15 patients with clinical Stage I disease, 12 with Stage II, and 16 with Stage III. Patients were treated with external irradiation to the pelvis and para-aortic regions combined with brachytherapy. None received chemotherapy.

RESULTS

The 5-year overall survival rate was 32% and the median overall survival was 2.2 years. The 5-year cause-specific survival rate was 49% and the median cause-specific survival was 2.7 years. The cause-specific survivals at 5 years were 47% for Stage I, 64% for Stage II, and 46% for Stage III. Tumor recurrence occurred in 20 patients. The sites of recurrence were in the pelvis only in 3, the pelvis and distant metastasis in 9, and distant metastasis only in 8 patients. Severe, grade 3 complications occurred in 2 patients. One patient developed an enterovaginal fistulas and 1 developed radiation myelitis.

CONCLUSION

Pelvic and para-aortic irradiation and brachytherapy resulted in a 49%, 5-year, cause-specific survival. Clinical tumor stage did not effect outcome. The majority of relapses occurred at distant sites. Toxicity was acceptable. Systemic chemotherapy should be considered as adjunctive therapy for these patients.

Cervical tumor control evaluated with ICRU 38 reference volumes and integrated reference air kerma

PURPOSE

The purpose of this investigation was to evaluate the relationship of ICRU 38 reference volumes and integrated reference air kerma to primary cervical tumor control.

MATERIALS AND METHODS

This retrospective study includes 1253 women with carcinoma of the uterine cervix treated with radiotherapy. Patients were treated from 1959 to 1993 at the Mallinckrodt Institute of Radiology. There were 39 women with stage Ia disease, 211 with stage Ib1, 88 with stage Ib2, 580 with stage 2, and 335 with stage 3 disease. Most patients with stage Ia disease were treated with low dose rate brachytherapy alone. All other patients were treated with external irradiation and low dose rate brachytherapy. External irradiation doses ranged from 8.2-63.8 Gy to the whole pelvis and an additional parametrial boost to deliver a total of 65-75 Gy to Point P depending on tumor stage. Low dose rate brachytherapy was delivered to the primary tumor with doses ranging from 40x10(4)-60x10(4) Gy cm(2) (integrated reference air kerma; IRAK). Isodose reference volumes (60-160 Gy) and point A doses were determined for all patients. Tumor control was defined as control of the primary cervical cancer with or without failure at other pelvic or distant sites.

RESULTS

The mean 60 Gy volume was calculated to be 139.5 cm(3) for stage Ia, 200.4 cm(3) for stage Ib1, 270.9 cm(3) for stage Ib2, 235 cm(3) for stage 2, and 293.4 cm(3) for stage 3. No patient with stage Ia disease had a failure in the cervix. For stage Ib1 tumors the mean 60 Gy volume was 219.1 cm(3) for those who failed in the cervix and 199.9 cm(3) for those who did not fail (P=0.73). For stage Ib2 tumors the mean 60 Gy volume was 354.4 cm(3) for those who failed and 260.2 cm(3) for those who did not fail (P=0.004). The mean 60 Gy volume was 249.3 cm(3) for those with stage 2 disease who failed and 233.8 cm(3) for those who did not fail (P=0.02). For patients with stage 3 cancer the mean 60 Gy volume was 321.6 cm(3) for those who failed and 287.3 cm(3) for those who did not fail (P=0.20). Reference volumes from 70-160 Gy were not statistically different within each stage for those who failed in the cervix compared to those who did not fail. Cervical recurrences by clinical stage did not have statistically significant differences for mean IRAK except for stage II disease (P=0.001).

CONCLUSION

Analysis of the 60-160 Gy reference volumes and IRAK failed to demonstrate a consistent positive increasing correlation of these values to primary cervical tumor control.

Comparison of clinical outcome in black and white women treated with radiotherapy for cervical carcinoma

BACKGROUND

The purpose of this investigation was to evaluate the significance of race on the cancer-specific survival outcome of women treated with radiotherapy for advanced-stage cancer of the uterine cervix.

METHODS

Data from 922 women with cancer of the uterine cervix treated with radiotherapy were reviewed. Patients were treated at the Mallinckrodt Institute of Radiology from 1959 through 1993. There were 576 women with clinical Stage II cancer and 346 women with clinical Stage III cancer. All women were treated following standard medical care treatment policies according to the stage of their disease. Data were analyzed by race and known treatment-related prognostic factors. Overall and cancer-specific survivals were evaluated.

RESULTS

The 5-year cancer-specific survivals for clinical Stage II were 66 and 61% (P = 0.56) for white and black women, respectively. The corresponding 5-year overall survivals were 60 and 51% (P = 0.02). The 5-year cancer-specific survivals for clinical Stage III were 38 and 47% (P = 0.34) for white and black women, respectively. The associated 5-year overall survivals were 32 and 40% (P = 0.37). No differences in treatment-related factors were identified.

CONCLUSIONS

In a cancer treatment system where black and white women with clinical Stage II and III cancer of the uterine cervix are all treated with radiotherapy alone, following standard treatment policies, no significant difference in cancer-specific survival outcome is shown. Multivariate analysis revealed that clinical stage and overall treatment time are significant variables affecting the control of tumor by radiotherapy. Overall survivals for the two racial groups are different and may be related to other non-cancer-related factors.

New trends in prostatic cancer research. Three-dimensional conformal radiation therapy (3-D CRT), brachytherapy, and new therapeutic modalities

In prostatic cancer research three-dimensional conformal radiation therapy (3-D CRT), brachytherapy and new therapeutic modalities have been applied. Treatment planning and delivery of radiation therapy have substantially evolved in the past 20 years. The treatment of localized carcinoma of the prostate with 3-D CRT is described, preliminary clinical results are presented and compared with those with standard radiation therapy (SRT). The benefit of 3-D CRT hypothetically could be linked to improved local tumor control because of a better coverage of the target volume with a specific dose of irradiation, less acute and late toxicity, possibility of carrying out dose-escalation studies. Intensity modulated radiation therapy (IMRT) may be particularly useful in some cases. Further efforts are necessary with collaboration of urologists and radiation oncologists to continue to explore approaches to optimally select and manage patients with localized prostate cancer. A reliable assessment of the impact of 3-D CRT and IMRT on outcome should come from prospective randomized long-term studies. As for brachytherapy, standardized protocols should be developed to objectively evaluate brachytherapy in localized prostatic cancer. Recently a great deal of interest has been focused on new therapeutic modalities with chemotherapeutic agents, a new agent named prostate specific enhancer, a regulatory element of the PSA gene is being tested. Laboratory and animal studies of the viral construct have been reported. A phase I human clinical trial is being initiated in the U.S.A. in patients with postirradiation hormone refractory prostate cancer.

Pyloroplasty improves long-term gastric emptying in rats undergoing fundoplication

BACKGROUND

Conflicting reports exist regarding the permanence of improved gastric emptying (GE) after fundoplication for gastroesophageal reflux in children.

METHODS

Changes in gastric volume (GV) and GE of a radiolabeled mixed meal induced by a Nissen fundoplication (NF) were compared with those with a NF plus pyloroplasty (NF + P). GE was measured preoperatively, 15 and 30 days postoperation, in 24 Sprague-Dawley rats; 12 had NF alone, and 12 had NF + P Results were expressed as percent gastric retention at 90 minutes (GR90). GV was measured at the same time periods in 20 additional rats.

RESULTS

NF rats had enhanced GE with reduction of preoperative GR90 from 37.6% to 23.7% at 15 days (P < .05); however, at 30 days the GR90 increased to 34.3%. NF + P rats had enhanced GE with reduction in GR90 from 37.2% to 20.8% at 15 days (P< .05), which persisted at 30 days (20.4%). Mean GV decreased from (1.36 mL/100 g body weight) preoperation to 0.86 at 15 days (P< .05) at 15 days in the NF group, and returned to 1.29 at 30 days. Mean GV decreased from 1.36 to 0.91 at 15 days in the NF + P rats and persisted at 0.90 at 30 days.

CONCLUSION

In the rat model, NF enhances GE transiently, whereas NF + P produces long-term enhancement of GE.

Methodology of research and practice for the third millennium: evidence-based medicine

In the past 10 years there have been significant scientific advances in biological sciences and health care. The growth in basic and translational research data to guide medical practice, which has an impact on health care costs has made it critical for clinicians to appraise and use published evidence for medical decisions. Evidence-based medicine should be strengthened and promoted to enhance the rationale and quality of medical care provided to our patients. Basic laboratory research and properly designed, relevant and timely prospective clinical trials should be strongly supported; patient participation must be increased to acquire more accurate information to develop innovative therapeutic strategies in oncology. New avenues in cancer detection and staging, as well as therapy, suggested by basic and translational laboratory research, must be vigorously pursued and adequately funded. Methodology for accurate cost accounting of medical care and cost-benefit studies needs further development. Technology assessment will substantially contribute to better utilization of scarce health care resources.

New trends in prostatic cancer research. Hormone therapy in localized carcinoma of the prostate

Seventy-five per cent of patients with carcinoma of the prostate exhibit some response to hormonal therapy. Emphasis from the very beginning to the present time has been on mechanisms of action. Studies on total androgen suppression were also developed for many years. Although the majority of the trials concerned locally advanced tumors, neo- or adjuvant hormonal therapy seems closely related to an increase in disease-free and metastasis-free survival, and local tumor control, no significant correlation was found between neo- or adjuvant radiotherapy and overall survival. Present ongoing studies are focused on patients with early cancer stage, PS > 70% and PSA < 20 ng/ml. In particular three areas are currently under investigation: dose escalation, particle therapy and radiotherapy combined with intermittent androgen suppression. Well-designed clinical trials are highly desirable to compare efficacy and specifically analyze patterns of failures with radical prostatectomy or irradiation, taking into account patient selection, staging methods, tumor characteristics, prognostic factors, etc. Endpoints should include survival, morbidity, and quality of life as well as cost-benefit of each therapeutic modality.

Three-dimensional conformal therapy or standard irradiation in localized carcinoma of prostate: preliminary results of a nonrandomized comparison

PURPOSE

We present preliminary results of a nonrandomized comparison of three-dimensional conformal radiation therapy (3D CRT) and standard radiation therapy (SRT) in localized carcinoma of the prostate in two groups of patients with comparable prognostic factors treated during the same period.

METHODS AND MATERIALS

Between January 1992 and December 1997, 146 patients were treated with 3D CRT and 131 with SRT alone for clinical stage T1c or T2 histologically confirmed carcinoma of the prostate. None of these patients received hormonal therapy. Mean follow-up for all patients is 3 years (range, 1-6 years). For 3D CRT, 7 intersecting fields were used (Cerrobend blocking or multileaf collimation) to deliver 68-73.8 Gy to the prostate; 3D dose distributions and dose-volume histograms (DVHs) of the planning target volume, bladder, and rectum were obtained. SRT consisted of bilateral 120 degrees rotational arcs, with portals with 2-cm margins around the prostate to deliver 68-70 Gy to the prostate. The criterion for chemical disease-free survival was a postirradiation prostate-specific antigen (PSA) (Tandem-R, Hybritech) value following the American Society for Therapeutic Radiology and Oncology guidelines. Symptoms during treatment were quantitated weekly, and late effects were assessed every 4-6 months.

RESULTS

DVHs showed a two-thirds reduction in normal bladder or rectum receiving 70 Gy or more with 3D CRT. Higher 5-year chemical disease-free survival was observed with 3D CRT (91% for T1c and 96% for T2 tumors) compared with SRT (53% and 58%, respectively). There was no statistically significant difference in chemical disease-free survival in patients with Gleason score of 4 or less (p = 0.83), but with Gleason score of 5-7, the 5-year survival rates were 96% with 3D CRT and 53% with SRT (p < or = 0.01). In 111 patients with pretreatment PSA of 10 ng/mL or less, treated with 3D CRT, the chemical disease-free rate was 96% vs. 65% in 94 patients treated with SRT (p < or = 0.01). In patients with PSA of 10. 1-20 ng/mL, the chemical disease-free survival rate for 26 patients treated with 3D CRT was 88% compared with 40% for 20 patients treated with SRT (p = 0.05). The corresponding values were 71% and 26%, respectively, for patients with PSA levels of greater than 20 ng/mL (p = 0.30). On multivariate analysis, the most important prognostic factors for chemical failure were pretreatment PSA (p = 0. 023), nadir PSA (p = 0.001), and 3D CRT technique (p = 0.033). Moderate dysuria and difficulty in urinating were reported by 2-5% of patients treated with 3D CRT in contrast to 6-9% of patients treated with SRT; moderate urinary frequency and nocturia were reported by 18-24% treated with 3D CRT and 18-27% of patients in the SRT group. The incidence of moderate loose stools/diarrhea, usually after the 4th week of treatment, was 3-5% in the 3D CRT patients and 8-19% in the SRT group. Late intestinal morbidity (proctitis, rectal bleeding) was very low (1.7%) in the 3D CRT group in contrast to the SRT patients (8%).

CONCLUSION

Three-dimensional CRT spares more normal tissues, yields higher chemical disease-free survival, and results in less treatment morbidity than SRT in treatment of Stage T1-T2 prostate cancer. Longer follow-up is needed to confirm these preliminary observations.

Intensity-modulated radiation therapy in head and neck cancers: The Mallinckrodt experience

The purpose of the study was to investigate the feasibility and the optimization of tomotherapy-based intensity-modulated radiation therapy (IMRT) in patients with head and neck cancer. From February 1997 to November 1997, 17 patients with squamous cell carcinoma of the head and neck were treated with IMRT. Patients were immobilized with a noninvasive mask and treated using a serial tomotherapy device on a 6 MV linear accelerator. Treatment planning was performed on a Peacock inverse planning system and prescription optimization was used to achieve the best plan for target coverage and parotid sparing. The treatment planning system process has a dosimetric characteristic of delivering different doses to different target structures simultaneously in each daily treatment; therefore, the biological equivalent dose was implemented using the linear-quadratic model to adjust the total dose to the target volume receiving a daily dose of less than 1.9 Gy. All eight patients with gross disease (six in the nasopharynx, two in the tonsil) and one patient with recurrent nasopharyngeal carcinoma received concurrent cisplatin chemotherapy. Six postoperative patients were treated with irradiation alone. Median follow-up was 2.2 years (range 2.6-1.8 years). All patients completed the prescribed treatment without unexpected interruption. Acute side effects were comparable to those of patients treated with conventional beam arrangements during the same period. No patient required gastrostomy during irradiation. The preliminary experience showed that the noninvasive immobilization mask yielded high positioning reproducibility for our patients. To spare the parotid gland, which is in the proximity of the target, a fraction of the target volume may not receive the prescribed dose. In the best-achievable plan of our studied cohort, only 27% +/- 8% of parotid gland volumes were treated to more than 30 Gy, while an average of 3.3% +/- 0.6% of the target volume received less than 95% of the prescribed dose. This is mainly related to the steep dose gradient in the region where the target abuts the parotid gland. The inverse planning system allowed us the freedom of weighting normal tissue-sparing and target coverage to select the best-achievable plan. Local control was achieved in eight patients with gross tumor; six were treated postoperatively. Of three reirradiated patients, two had symptomatic improvement but persistent disease, and one is without evidence of disease. In summary, a system for patient immobilization, setup verification, and dose optimization for head and neck cancer with parotid sparing without significantly compromising target coverage is being implemented for a tomotherapy-based IMRT plan at the Mallinckrodt Institute of Radiology. The initial clinical experience in tumor control is promising, and no severe adverse acute side effects have been observed. Further refining of delivery technology and the inverse planning system, gaining clinical experience to address target definition and dose inhomogeneity within the targets, and understanding the partial volume effect on normal tissue tolerance are needed for IMRT to excel in the treatment of head and neck cancer. Int. J. Cancer (Radiat. Oncol. Invest.) 90, 92-103, (2000).

Effects of dietary fat on benz-a-pyrene-induced forestomach tumorigenesis in mice chronically exposed to arsenic

The modulating effect of As (As2O3) in drinking water plus dietary fatty acids on benzo-a-pyrene (BP) induced forestomach tumorigenesis was assayed in mice fed with corn oil (CO), Olein (O), palmstearin (PS) and cod liver oil (CLO) enriched formulae, and a mixed-fat (S-stock) diet during 28 weeks. Neither pre-or neoplastic lesions were recorded in esophagus or forestomach of mice treated with As alone. CLO diet showed a protective effect. Indeed, multiple epidermal hyperplasia were significantly reduced compared to S group and a reduction in papillomas multiplicity with respect to S, CO and O groups was also observed. Mice fed on PS formula showed minor papillomas per mouse with respect to CO and O. These results indicate that As plus BP did not exhibit any synergistic effect on the development of epidermoid tumor lesions, whereas CLO diet exerted antipromoting activity . In spite of their common essential fatty acid deficiency (EFAD) condition, PS and O lots showed contradictory results. Hence, the dietary enrichment in 18:1 n-9 (O diet) per se, and not the EFAD state, may play a deleterious role. Corn diet showed no promoting activity on the epidermoid tumor development in this model.