Ammonia flux into the atmosphere from a grazed pasture.

A micrometeorological technique has been used to measure the flux of ammonia and related gaseous nitrogen compounds into the atmosphere from a pasture grazed by sheep. During 3 weeks in late summer, the average daily flux density of nitrogen in these forms was 0.26 kilogram per hectare. This is a substantial part of the nitrogen turnover in grazed pastures.

Comparative measures of single-wall carbon nanotube dispersion.

Model composites of DNA-wrapped single-wall carbon nanotubes in poly(acrylic acid) are used to evaluate metrics of nanotube dispersion. By varying the pH of the precursor solutions, we introduce a controlled deviation from ideal behavior. On the basis of small-angle neutron scattering, changes in near-infrared fluorescence intensity are strongly correlated with dispersion, while optical absorption spectroscopy and resonant Raman scattering are less definitive. Our results represent the first systematic comparison of currently accepted measures of nanotube dispersion.

Enhancing single-wall carbon nanotube properties through controlled endohedral filling.

Chemical control of the endohedral volume of single-wall carbon nanotubes (SWCNTs) via liquid-phase filling is established to be a facile strategy to controllably modify properties of SWCNTs in manners significant for processing and proposed applications. Encapsulation of over 20 different compounds with distinct chemical structures, functionalities, and effects is demonstrated in SWCNTs of multiple diameter ranges, with the ability to fill the endohedral volume based on the availability of the core volume and compatibility of the molecule's size with the cross-section of the nanotube's cavity. Through exclusion of ingested water and selection of the endohedral chemical environment, significant improvements to the optical properties of dispersed SWCNTs such as narrowed optical transition linewidths and enhanced fluorescence intensities are observed. Examples of tailoring modified properties towards applications or improved processing by endohedral passivation are discussed.

Feasibility and acceptability of a proposed infant feeding intervention trial for the prevention of type I diabetes.

OBJECTIVE: To determine the feasibility of a randomized double-blind controlled trial of an infant formula without intact cow's-milk protein for preventing type I diabetes in high-risk children. RESEARCH DESIGN AND METHODS: We surveyed 83 people who either were parents of a child with type I diabetes or were pregnant women with type I diabetes in the ambulatory diabetes and obstetrics clinics in a university hospital. After a written and verbal description of the cow's milk-diabetes hypothesis, participants were asked to sign a sham consent form. A questionnaire designed to explore factors affecting their decision to either sign or not sign the consent form, as well as infant-feeding patterns, was subsequently administered. RESULTS: Overall, 69.9% (95% confidence interval, 60.0-79.8%) consented to participation in the proposed randomized trial. The decision to consent was not affected by the degree of belief in the cow's milk-diabetes hypothesis, the child's risk of diabetes, the respondent's demographic data, or infant feeding habits. CONCLUSIONS: A randomized feeding intervention study is an acceptable and feasible way to determine whether avoidance of cow's-milk protein during the first 6 months of life prevents type I diabetes in North American children.

Cerebellar medulloblastoma: the importance of posterior fossa dose to survival and patterns of failure.

Fifty patients with biopsy-proven cerebellar medulloblastoma were retrospectively analyzed for prognostic factors, survival and patterns of failure. Five- and ten-year actuarial survivals for the entire group were 51% and 42%. Survival and local control were significantly better for the 21 patients who received doses greater than 5000 rad to the posterior fossa (85% and 80% respectively) than for the remaining patients (38% and 38%, respectively). Significant prognostic factors included achievement of local control in the posterior fossa (p = .0001) and dose to the posterior fossa (p = .0005). Sex, age, duration of symptoms, extent of surgery and initial T-stage of disease were not significant. Posterior fossa was the predominant site of failure (71% of failures), but 10% of patients failed in the cerebrum and 12% outside the CNS. This experience confirms that survival rates of 70-80% are achievable with current treatment policies but accurate and consistent dose delivery to the posterior fossa is essential.

Prognostic factors and results of radiotherapy alone in the management of pituitary adenomas.

Prognostic factors and results of therapy were analyzed in a retrospective review of 70 patients with pituitary adenomas treated with radiotherapy alone from January 1954 through December 1982 at the Radiation Oncology Center, Mallinckrodt Institute of Radiology. The 10-year overall and disease-free survival was 77.8 and 76.0%. The expected survival for an age-, sex-, and race-matched population was not significantly greater at 87.2%. The 10-year disease-free survival for the distinct tumor types was 100% for Cushing's disease, 82.3% for patients with amenorrhea/galactorrhea, 79.6% for non-functioning adenomas, 69.0% for acromegaly, and 66.7% for Nelson's syndrome. Prognostic variables analyzed were age, race, sex, tumor type, tumor extent, visual field defects at diagnosis, and volume irradiated. Only the presence of visual field defects at diagnosis conferred a poor prognosis (p less than 0.001). There was a tendency toward superior tumor control with radiation doses greater than 4500 cGy (p = 0.15). The median time to progression of disease was 4.2 years, with the last failure occurring at 12 years following the completion of radiotherapy. Severe complications were apparent in 5 patients (7.1%), including one death from central nervous system radionecrosis.

Role of irradiation in the management of superior vena cava syndrome.

The records of 125 patients treated for superior vena cava syndrome secondary to malignant disease were reviewed retrospectively. The mean age of patients was 55 years. Bronchogenic carcinoma was the cause of the syndrome in 79% of cases, malignant lymphoma 18%, and other tumors 6%. Approximately 80% of the patients obtained good to excellent symptomatic relief. High initial dose radiation therapy (300-400 cGy daily for three fractions) yielded good symptomatic relief in less than 2 weeks in 70% of patients; conventional dose radiation therapy (200 cGy daily, five weekly fractions) yielded the same response in 56% of patients (p = 0.09). Lymphoma patients displayed a 1 year survival of 41%, small cell carcinoma 24%, and other types of bronchogenic carcinoma 17%. Combination of radiation and chemotherapy did not improve response rate, degree of symptomatic relief or long-term survival. Patients exhibiting symptomatic relief within 30 days had a significantly better survival rate than those who did not (p = 0.002). Thirteen percent of patients showed a recurrence of superior vena cava syndrome. There was no correlation between tumor regression and symptomatic relief. Side effects of therapy were minimal; dysphagia was the most common complaint (26% of patients).

Results of radiotherapy in recurrent endometrial carcinoma: a retrospective analysis of 51 patients.

A retrospective analysis was performed of 51 patients with locoregional recurrence of endometrial carcinoma, treated by radiotherapy between 1959 and 1986. There were 17 patients (33%) with isolated vaginal recurrence, 12 patients (24%) with vaginal recurrence with pelvic extension, 7 patients (14%) with pelvic recurrence only, and 15 patients (29%) with simultaneous locoregional and distant failure. Eighty percent of the recurrences occurred within 3.5 years from primary treatment; time to relapse was shorter in patients with advanced-stage, high-grade malignancy at original diagnosis. Locoregional control was achieved in 18 patients (35%). Complete tumor regression in the vagina, irrespective of extravaginal pelvic disease status or distant metastasis, occurred in 28 of 34 patients with vaginal involvement (82%). The 5- and 10-year overall actuarial survivals for all patients were 18 and 12.5%, respectively. The 5- and 10-year progression-free survivals of patients with isolated vaginal recurrences were 40% and 29%, respectively; the 5-year progression-free survival of patients with vaginal recurrence with pelvic extension was 20%. There were no survivors beyond 1.5 years among patients with pelvic recurrence (p = 0.02). All patients with simultaneous locoregional and distant failure were dead by 3.5 years. Stage at original diagnosis, time to relapse from primary treatment, histologic pattern, and grade of malignancy were prognosticators of survival. Five patients (10%) developed a total of ten radiation-related sequelae.

Palliative radiotherapy for inoperable carcinoma of the lung: final report of a RTOG multi-institutional trial.

Between June 1973 and February 1979, 409 patients with inoperable advanced non-oat cell carcinoma of the lung were randomized on RTOG protocol 73-02. Three treatment arms were evaluated: 40 Gy split course, 30 Gy continuous course, and 40 Gy continuous course. Patients were also randomized to receive cytoxan or no further therapy following irradiation. Three hundred sixteen patients were evaluable. Palliation of symptoms was achieved in 60% with 1/4 of the patients becoming symptom-free. Complete regression of local and regional tumor was produced in 15% and partial regression in 26%. There is no significant difference between the treatment arms in these objective response rates. Median survival times were approximately 6 months. No significant benefit was demonstrated by the adjuvant use of Cytoxan. Although the number of complete responses produced was relatively small, patients achieving a complete response had a significantly longer median survival than the remaining patients, i.e., 14.5 months versus 6 months. Significant toxicity occurred in fewer than 6% of patients. Radiation pneumonitis counted for the majority of these adverse reactions. Toxicity occurred somewhat more often in the group treated with 40 Gy split course therapy. Implications for further studies are discussed.

Large fraction radiotherapy plus misonidazole for treatment of advanced lung cancer: report of a phase I/II trial.

From August 1978 through December 1979, 51 patients with advanced non-oat cell carcinoma of the lung were enrolled in a Phase I/II trial sponsored by the Radiation Therapy Oncology Group (RTOG) employing misonidazole (a 2-nitroimidazole) as a hypoxic cell sensitizer and radiation. The purpose of this study was to test drug and radiation tolerance and to assess the short term efficacy of this unconventional treatment. Tumor doses of 600 rad wer given twice weekly for three weeks for a total of 3600 rad, preceded four to six hours by misonidazole in a dose of 2 gm/m2 or 1.75 gm/m2, administered orally. Forty-nine patients were evaluable. Serious toxicity from this treatment was rare. Grade 2 or 3 peripheral neuro-toxicity occurred in eight of 24 patients (33%) with drug doses of 2 gm/m2 and in four of 26 patients (15%) who received 1.75 gm/m2. Grade 3 or 4 central nervous system toxicity occurred in two patients. Two patients developed serious late radiation complications: one patient had a transverse myelitis that appeared one year following delivery of 3600 rad to the spinal cord; a second patient developed a tracheoesophageal fistula and pericarditis eight months following treatment. Objective responses were reported in 67% of patients (complete in 18%); 70% of the patients died with a median survival time of nine months. Of 32 patients eligible for 12 month follow-up, 34% survived more than one year. Patterns of relapse after initial treatment and comparison with results from other RTOG trials using conventional fractionation are discussed.

Dosimetry of CT-guided volumetric IR-192 brain implant.

Over the past 2 years, an afterloading technique has been developed and refined to implant radioactive Ir-192 sources into brain tumors. The implantation procedure integrates a stereotaxic system with computerized tomography (CT), which provides tumor position, volume, and guides the placement of catheters. A radiolucent ring-frame immobilizes the head as holes are made at 1 cm intervals with the aid of a template. Catheters containing dummy sources 1 cm apart are then inserted to the desired depth, and their position verified in three dimensions to insure complete coverage of visible tumor volume as defined by contrast enhancement. Once catheters are secured, the anesthetized patient is moved to the intensive care unit where the dummy sources are replaced by ribbons of Ir-192 seeds (specific activity 0.6-1.0 mg Ra eq). CT scans with the dummy sources in place are used to designate spatial coordinates of the active sources. A computer program converts position data and source strength into isodose contours in any plane. The implant duration (70-100 hours) for the desired dose to the tumor periphery (60-120 Gy) is then calculated. Dose rate contours are superimposed on preimplant CT scans. Maximum and minimum doses are determined in each of the various planes. Verification dosimetry has been carried out with thermoluminescent dosimeters placed in a catheter located in a plane along the tumor periphery. In vivo isodose values compared to idealized plans agree within +/-5%-10%.

Prognostic factors and results of surgery and postoperative irradiation in the management of pituitary adenomas.

Prognostic factors and results of therapy were analyzed in a retrospective examination of 121 patients with pituitary adenomas treated with surgery and postoperative irradiation (RT) from January 1954 through December 1982 at the Radiation Oncology Center, Mallinckrodt Institute of Radiology. The 10-year overall and disease-free survival for all patients was 85.1 and 89.4%. The expected survival for an age-, gender-, and race-matched population was not significantly distinct at 85.3% (p = 0.72). Follow-up of 94 surviving patients ranged from 3.4 to 29.5 years (mean, 11.7). Statistical analysis was performed for multiple prognostic factors including age, race, gender, disease bulk, visual field symptoms, disease type, surgical approach, and irradiation dose and volume. The only prognostic variable identified by univariate analysis to significantly alter disease-free survival was irradiation dose. Patients receiving 5000-5400 cGy had a tumor control rate of 94.1% (64/68) compared to 85.0% (17/20) for 4000-4999 cGy, 75.0% (18/24) for 3000-3999 cGy, and 28.6% (2/7) for less than 3000 cGy (p = 0.000059). Factors evaluated but established to be insignificant were age, race, gender, disease bulk, visual field symptoms, disease type, surgical approach, and irradiated volume. The 10-year disease-free survival by classification was 93.3% for patients with amenorrhea/galactorrhea, 89.9% for non-functioning adenomas, and 76.4% for acromegaly (p = 0.21). Overall improvement in visual field defects subsequent to treatment occurred in 48.4% (44/91) of those with visual field defects before RT and was significantly correlated with RT dose. The median time to progression of disease was 10.2 years with the last failure occurring at 25 years following the fulfillment of RT. Severe complications related to RT were apparent in 1.7% (2/121). None were known to have endured brain radionecrosis. Serious surgical complications occurred in 9.9% (12/121).

Radiation therapy alone or combined with misonidazole in the treatment of locally advanced non-oat cell lung cancer: report of an RTOG prospective randomized trial.

From September 1979 to February 1983, 268 patients with unresectable, locally advanced (RTOG Stage III), non-small cell lung cancer were randomized to receive radiation therapy alone (RT) (50 Gy large field and 10 Gy boost), or combined with misonidazole (400 mg/m2 2-4 hr prior to RT daily for 5-6 weeks to a maximum dose of 12 g/m2 or until tumor progression). One hundred twenty-three patients who received irradiation alone and 116 given RT + misonidazole were evaluable for toxicity, time to tumor progression, and survival as of April 1987. The distribution of patient characteristics was similar in both treatment groups; 59% of the patients had a Karnofsky score of 90 or better, 53% had adenocarcinoma or large cell tumors, and 47% had Stage T3 tumors. Complete tumor regression was reported for 33 (27%) patients treated with radiation therapy alone and 24 (21%) who received misonidazole + RT. Median survival was 8 months with RT alone and 7.4 months with misonidazole + RT. Ninety-five percent of the patients have died. Seventy percent of the patients treated with radiation alone and 77% of those treated with misonidazole + RT died of progressive disease. Three patients treated with radiation alone and two with RT + misonidazole died subsequent to radiotherapy-related pneumonitis or pulmonary fibrosis. There was no significant improvement in response rates, local control, or survival for patients who received daily misonidazole along with irradiation compared with patients treated by irradiation alone.

Validation and predictive power of Radiation Therapy Oncology Group (RTOG) recursive partitioning analysis classes for malignant glioma patients: a report using RTOG 90-06.

PURPOSE: The recursive partitioning analysis (RPA) classes for malignant glioma patients were previously established using data on over 1500 patients entered on Radiation Therapy Oncology Group (RTOG) clinical trials. The purpose of the current analysis was to validate the RPA classes with a new dataset (RTOG 90-06), determine the predictive power of the RPA classes, and establish the usefulness of the database norms for the RPA classes. PATIENTS AND METHODS: There are six RPA classes for malignant glioma patients that comprise distinct groups of patients with significantly different survival outcome. RTOG 90-06 is a randomized Phase III study of 712 patients accrued from 1990 to 1994. The minimum potential follow-up is 18 months. The treatment arms were combined for the purpose of this analysis. There were 84, 13, 105, 240, 150, and 23 patients in the RPA Classes I-VI from RTOG 90-06, respectively. RESULTS: The median survival times (MST) and 2-year survival rates for the six RPA classes in RTOG 90-06 are compared to those previously published. The MST and 2-year survival rates for the RTOG RPA classes were within 95% confidence intervals of the 90-06 estimates for Classes I, III, IV, and V. The RPA classes explained 43% of the variation (squared error loss). By comparison, a Cox model explains 30% of the variation. The RPA classes within RTOG 90-06 are statistically distinct with all comparisons exceeding 0.0001, except those involving Class II. A survival analysis from a prior RTOG study indicated that 72.0 Gy had superior outcome to literature controls; analysis of this data by RPA classes indicates the survival results were not superior to the RTOG database norms. CONCLUSION: The validity of the model is verified by the reliability of the RPA classes to define distinct groups with respect to survival. Further evidence is given by prediction of MST and 2-year survival for all classes except Class II. The RPA classes explained a good portion of the variation in survival outcome in the data. Lack of correlation in RPA Class II between datasets may be an artifact of the small sample size or an indication that this class is not distinct. The validation of the RPA classes attests to their usefulness as historical controls for the comparison of future Phase II results.

Isolated local-regional recurrence of breast cancer following mastectomy: radiotherapeutic management.

Two hundred twenty-four patients with their first, isolated local-regional recurrence of breast cancer were irradiated with curative intent. Patients who had previous chest wall or regional lymphatic irradiation were not included in the study. With a median follow-up of 46 months (range 24 to 241 months), the 5- and 10-year survival for the entire group were 43% and 26%, respectively. Overall, 57% of the patients were projected to be loco-regionally controlled at 5 years. The 5-year local-regional tumor control was best for patients with isolated chest wall recurrences (63%), intermediate for nodal recurrences (45%), and poor for concomitant chest wall and nodal recurrences (27%). In patients with solitary chest wall recurrences, large field radiotherapy encompassing the entire chest wall resulted in a 5- and 10-year freedom from chest wall re-recurrence of 75% and 63% in contrast to 36% and 18% with small field irradiation (p = 0.0001). For the group with recurrences completely excised, tumor control was adequate at all doses ranging from 4500 to 7000 cGy. For the recurrences less than 3 cm, 100% were controlled at doses greater than or equal to 6000 cGy versus 76% at lower doses. No dose response could be demonstrated for the larger lesions. The supraclavicular failure rate was 16% without elective radiotherapy versus 6% with elective radiotherapy (p = 0.0489). Prophylactic irradiation of the uninvolved chest wall decreased the subsequent re-recurrence rate (17% versus 27%), but the difference is not statistically significant (p = .32). The incidence of chest wall re-recurrence was 12% with doses greater than or equal to 5000 cGy compared to 27% with no elective radiotherapy, but again was not statistically significant (p = .20). Axillary and internal mammary failures were infrequent, regardless of prophylactic treatment. Although the majority of patients with local and/or regional recurrence of breast cancer will eventually develop distant metastases and succumb to their disease, a significant percentage will live 5 years. Therefore, aggressive radiotherapy should be used to provide optimal local-regional control.(ABSTRACT TRUNCATED AT 400 WORDS)

Carcinoma of the nasopharynx: factors affecting prognosis.

This is a retrospective analysis of 143 patients with histologically confirmed epidermoid carcinoma of the nasopharynx treated with definitive irradiation. Patients were treated with a combination of Cobalt-60, 4 to 6 MV X rays, and 18 to 25 MV X rays to the primary tumor and the upper necks, excluding the spinal cord at 4000 to 4500 cGy to total doses of 6000 to 7000 cGy. At 10 years the actuarial primary tumor failure rate was 15% in T1, 25% in T2, 33% in T3, and 60% in T4 lesions. The corresponding failure rate in the neck was 18% for N0, 14% for N1, and 33% for N2 and N3 lymphadenopathy. The incidence of distant metastasis was related to the stage of the cervical lymphadenopathy: 16% in patients with N0-N1 nodes compared with 40% in the N2-3 node group. The actuarial 10-year disease-free survival rate was 55% to 60% for T1-3N0-1 tumors, 45% for T1-3N2-3 tumors, 35% for T4N0-1, and 20% for T4N2-3 lesions. The overall 10-year survival rate was about 40% for patients with T1-2N0-1 tumors, 30% for those with T3 any N stage tumors, and only 10% for the patients with T4 lesions. Multivariate analysis showed that tumor stage and histological type, cranial nerve involvement, patient age, and doses of irradiation to the nasopharynx were significant prognostic factors for local/regional tumor control. Increasing doses of irradiation resulted in nasopharynx tumor control in 80% of the patients receiving 6600 to 7000 cGy and 100% of those receiving over 7000 cGy in the T1, T2, and T3 tumors. However, the tumor control rate did not rise above 55% even for doses over 7000 cGy in the T4 lesions. Local tumor control was higher in patients who had simulation (55/78 = 71%) compared with those on whom simulation was not performed (34/61 = 56%) (p = 0.10). Moreover, patients with more than 75% of the reviewed films judged as adequate had 69% primary tumor control (66/96) compared with 53% (23/43) for those with fewer than 75% adequate portal films (p = 0.07).

Survival following locoregional recurrence of breast cancer: univariate and multivariate analysis.

Although prognostic variables for locoregional recurrence of breast cancer have been evaluated by univariate analysis, multifactorial analysis has not been previously performed. In the present study, survival following chest wall and/or regional lymphatic recurrence was determined in 230 patients with locoregionally recurrent breast cancer without evidence of distant metastases treated at the Radiation Oncology Center, Mallinckrodt Institute of Radiology and affiliated hospitals. Multifactorial analysis demonstrated that the site of recurrences correlated most strongly with overall survival (p = 0.001). The 5-year actuarial overall survival was 44-49% for patients with isolated chest wall, axillary, and internal mammary lymph node recurrence. Patients with either supraclavicular, multiple lymphatic, or concomitant chest wall and lymphatic recurrence had an 21-24% 5-year overall survival. The 5-year disease-free survival was 28-37% for patients with chest wall, axillary, or internal mammary recurrences compared to 4-13% for those with supraclavicular, chest wall and lymphatic, or those with multiple sites of lymphatic recurrence. Disease-free interval from mastectomy to recurrence was also found to be a significant prognostic factor for overall survival (p = 0.005). Fifty percent of patients with a disease-free interval of at least 2 years survived 5 years following locoregional relapse, compared to 35% for those with disease-free interval of less than 2 years. In the subset of patients with small chest wall recurrences (excised or less than 3 cm) and a disease-free interval of at least 2 years, the 5-year overall and disease-free survivals were 67% and 54%, respectively. These results suggest that subsets of patients with locoregional recurrence of breast cancer can survive for long periods of time. The conventional wisdom that chest wall and/or regional nodal recurrence following mastectomy uniformly confers a dismal prognosis is not necessarily true.

Clinical stage I endometrial cancer: prognostic factors for local control and distant metastasis and implications of the new FIGO surgical staging system.

A retrospective analysis is reported in 858 patients with clinical Stage I carcinoma of the endometrium treated definitively with combined irradiation and total abdominal hysterectomy and bilateral salpingo-oophorectomy (TAH-BSO) from January 1960 through December 1986. Most patients received a preoperative intracavitary insertion (3500-4000 mgh to the uterus and a 6500 cGy surface dose to the upper vagina) followed by a TAH-BSO within 1-2 weeks. Some patients received postoperative external beam irradiation (2000 cGy whole pelvis and an additional 3000 cGy to the parametria, with a midline stepwedge) when factors such as deep myometrial invasion were present. Occasionally patients were treated with a preoperative intracavitary insertion and preoperative external beam irradiation (2000 cGy whole pelvis). The 5-year progression-free survivals by FIGO (1988) surgical stage were 93% for IA, 90% for IB, and 91% for Stage IC. An analysis of multiple variables was performed to ascertain their prognostic significance. Factors that significantly affected the 5-year progression-free survivals by univariate analysis were grade (grade 1 = 95%, grade 2 = 88%, grade 3 = 73%; p less than 0.0001), histology (adenoacanthoma = 96%, clear cell = 89%, adenocarcinoma = 89%, papillary = 81%, adenosquamous = 80%; p = 0.04), lower uterine segment involvement (uninvolved = 89%, involved = 73%; p = 0.006), depth of myometrial invasion (no residual tumor = 91%, limited to the endometrium = 96%, less than 1/3 myometrial penetration = 92%, 1/3 - 2/3 = 100%, greater than 2/3 = 50%; p = 0.02), peritoneal cytology (negative = 92%, positive = 56%, p less than 0.0001), uterine serosal involvement (uninvolved = 89%, involved = 55%; p less than 0.0001), vascular space invasion (absent = 89%, present = 75%; p = 0.001), and the presence of extrauterine disease (absent = 90%, present = 64%; p less than 0.0001). A multivariate analysis of these prognostic variables showed that histological grade (p = 0.001), peritoneal cytology (p = 0.004), and uterine serosal involvement were prognostic for local failure and that peritoneal cytology (p less than 0.001), grade (p = 0.001), age (p = 0.002), and extrauterine disease (p = 0.02) were prognostic for the development of distant metastasis.

Age as a prognostic factor for breast and regional nodal recurrence following breast conserving surgery and irradiation in stage I and II breast cancer.

PURPOSE: To evaluate the association between age and breast/regional nodal relapse following breast conserving surgery and irradiation. METHODS AND MATERIALS: The results of treatment in 511 patients with 519 Stage I and II breast cancers treated at Mallinkrodt Institute of Radiology and affiliated hospitals between 1958 and 1988 were reviewed. RESULTS: Seventy women, of whom 96% had axillary dissections, were 39 years of age or younger. These young patients were more likely to have chemotherapy (p < 0.0001), and tumor bed reexcision (p < 0.01), and less likely to have an undissected axilla (p < 0.01), or estrogen receptor positive tumor (p = 0.02) than the older women (> 40 years). Although breast recurrence tended to appear earlier in the younger patients (12% at 5 years for those < 40 years vs. 6% at 5 years for those older), by 7 years the breast failure rate for the two groups was the same (12%), p = 0.13. In the 37 women 35 years of age or younger, the actuarial rate of breast recurrence was 9% at 7 years. Compared to other series in the literature, in which cancers were grossly excised without regard to the microscopic margins of resection, and reexcision was not routinely performed, young women treated with breast conserving surgery and irradiation at our institution frequently underwent reexcision of the tumor bed (57%), and had negative pathologic margins of resection (75%). Regional nodal relapse was in general uncommon, and not seen with increased frequency in the youngest cohort. CONCLUSION: Our experience suggests that young age is not a contraindication to breast conserving surgery and irradiation. Although breast cancers in this cohort may have certain features rendering them prone to local failure, we believe this risk can be mitigated by appropriate patient selection and optimal surgical resection.

Advances in 3-dimensional radiation treatment planning systems: room-view display with real time interactivity.

PURPOSE: We describe our 3-dimensional (3-D) radiation treatment planning system for external photon and electron beam 3-D treatment planning which provides high performance computational speed and a real-time display which we have named "room-view" in which the simulated target volumes, critical structures, skin surfaces, radiation beams and/or dose surfaces can be viewed on the display monitor from any arbitrary viewing position. METHODS AND MATERIALS: We have implemented the 3-D planning system on a graphics superworkstation with parallel processing. Patient's anatomical features are extracted from contiguous computed tomography scan images and are displayed as wireloops or solid surfaces. Radiation beams are displayed as a set of diverging rays plus the polygons formed by the intersection of these rays with planes perpendicular to the beam axis. Controls are provided for each treatment machine motion function. Photon dose calculations are performed using an effective pathlength algorithm modified to accommodate 3-D off-center ratios. Electron dose calculations are performed using a 3-D pencil beam model. RESULTS: Dose distribution information can be displayed as 3-D dose surfaces, dose-volume histograms, or as isodoses superimposed on 2-D gray scale images of the patient's anatomy. Tumor-control-probabilities, normal-tissue-complication probabilities and a figure-of-merit score function are generated to aid in plan evaluation. A split-screen display provides a beam's-eye-view for beam positioning and design of patient shielding block apertures and a concurrent "room-view" display of the patient and beam icon for viewing multiple beam set-ups, beam positioning, and plan evaluation. Both views are simultaneously interactive. CONCLUSION: The development of an interactive 3-D radiation treatment planning system with a real-time room-view display has been accomplished. The concurrent real-time beam's-eye-view and room-view display significantly improves the efficacy of the 3-D planning process.