A simple soil mass correction for a more accurate determination of soil carbon stock changes.

Agricultural soils can act as a sink for large quantities of soil organic carbon (SOC) but can also be sources of carbon to the atmosphere. The international standard for assessing SOC stock and measuring stock change stipulates fixed depth sampling to at least 30 cm. The tendency of bulk density (BD) to decrease with decreasing disturbance and increasing SOC concentration and the assumption of constant SOC and BD within this depth profile promotes error in the estimates of SOC stock. A hypothetical but realistic change in BD from 1.5 to 1.1 g cm-3 from successive fixed depth sampling to 30 cm underestimates SOC stock change by 17%. Significant effort has been made to evaluate and reduce this fixed depth error by using the equivalent soil mass (ESM) approach, but with limited adoption. We evaluate the error in SOC stock assessment and change generated from fixed depth measurements over time relative to the ESM approach and propose a correction that can be readily adopted under current sampling and analytical methods. Our approach provides a more accurate estimate of SOC stock accumulation or loss that will help incentivize management practice changes that reduce the environmental impacts of agriculture and further legitimize the accounting practices used by the emerging carbon market and organizations that have pledged to reduce their supply chain greenhouse gas (GHG) footprints.

Tomography reconstruction of beams extracted from an ion source.

Commissioning of the CANREB (CANadian Rare isotope facility with Electron Beam ion source) system and its associated beamlines has recently begun at TRIUMF. At the head of this beamline is an ion source used to produce stable alkaline ions with energy up to 60 keV for the CANREB system. Throughout commissioning, it is essential to have a means of verifying beam quality and ensuring that the required beam parameters along the beamline are met. This is accomplished using tomography reconstruction, which consists of taking one-dimensional scans at different projections and reconstructing an image of the beam in two dimensions using the maximum entropy algorithm. Tomography enables the visualization of the shape of the beam as well as the investigation into the possible presence of aberrations. Initially, tomography reconstruction is performed by using simulated beam profiles at the measurement locations and is then performed by using measured beam profiles. Additionally, these measurements are benchmarked by fitting the initial beam parameters in our beam optics model, and the results are presented.

The ECRIS charge state breeding project at TRIUMF.

The performance of charge state breeding with an electron cyclotron resonance (ECR) ion source intended to increase the charge state of online produced radioactive ions at the ISAC facility at TRIUMF has been investigated. A 14 GHz PHOENIX from PANTECHNIK has been setup on a test bench. Singly charged ions have been produced with several ion sources typical for the on-line operation and were injected into the charge breeder. The main purpose of the tests has been the optimization of the efficiency for the charge breeding into the desired charge state. Maximum efficiencies reached so far with the standard one step deceleration of the ions in front of the plasma are up to about 6% for noble gas ions and about 3.5% for alkalines. As ion optics simulations show, the acceptance can be increased by a two step deceleration. In order to meet the velocity acceptance of the accelerator at different A/q values a similar two gap acceleration system for the highly charged ions has been installed to allow the source to run at different voltages. For the further beam transport to the accelerator, cross sections for charge exchange of the highly charged ions with the residual gas have been determined.

Off-line ion source terminal for ISAC at TRIUMF.

The off-line ion source (OLIS) terminal consists of a microwave cusp ion source, either a surface ion source or a hybrid surface-arc discharge ion source and an electrostatic switch that allows selecting any one of the sources without mechanical intervention. These sources provide variety of beams to ISAC experiments, for commissioning the accelerators, for setting up the radioactive experiments, and for tuning the beam lines. The microwave ion source has been operational since 1995 and provides singly and doubly charged beams from various stable isotopes for many ISAC experiments at high and low energy areas. Originally its prime goal was to provide beams from gaseous elements, but later two ovens and a sputtering system were added in order to provide beams from liquids and from solids. The surface ion source installed in 2002 can provide low energy spread beams from alkali and semialkali elements. It also has three separate ovens and an ionizer. Therefore, it can provide three different temperature regions simultaneously to provide different beams to ISAC. It is mainly used for laser spectroscopy experiments and other experiments, which require a finite beam quality. A hybrid surface-arc discharge ion source was also developed and installed in order to meet specific demands from experiments. This source terminal is now automated for start up and for mass selection. It is capable of providing stable beams for months without maintenance and it is also capable of providing negative ion beams if required. To date, over 40 different isotopes including many rear isotopes were delivered to various experiments from the OLIS source terminal. Performances of the ion sources and some of the results are discussed.

An electron beam ion trap and source for re-acceleration of rare-isotope ion beams at TRIUMF.

Electron beam driven ionization can produce highly charged ions (HCIs) in a few well-defined charge states. Ideal conditions for this are maximally focused electron beams and an extremely clean vacuum environment. A cryogenic electron beam ion trap fulfills these prerequisites and delivers very pure HCI beams. The Canadian rare isotope facility with electron beam ion source-electron beam ion sources developed at the Max-Planck-Institut für Kernphysik (MPIK) reaches already for a 5 keV electron beam and a current of 1 A with a density in excess of 5000 A/cm2 by means of a 6 T axial magnetic field. Within the trap, the beam quickly generates a dense HCI population, tightly confined by a space-charge potential of the order of 1 keV times the ionic charge state. Emitting HCI bunches of ≈107 ions at up to 100 Hz repetition rate, the device will charge-breed rare-isotope beams with the mass-over-charge ratio required for re-acceleration at the Advanced Rare IsotopE Laboratory (ARIEL) facility at TRIUMF. We present here its design and results from commissioning runs at MPIK, including X-ray diagnostics of the electron beam and charge-breeding process, as well as ion injection and HCI-extraction measurements.

Randomized trial of high-dose chemotherapy and blood cell autografts for high-risk primary breast carcinoma.

BACKGROUND: Uncontrolled studies have reported encouraging outcomes for patients with high-risk primary breast cancer treated with high-dose chemotherapy and autologous hematopoietic stem cell support. We conducted a prospective randomized trial to compare standard-dose chemotherapy with the same therapy followed by high-dose chemotherapy. PATIENTS AND METHODS: Patients with 10 or more positive axillary lymph nodes after primary breast surgery or patients with four or more positive lymph nodes after four cycles of primary (neoadjuvant) chemotherapy were eligible. All patients were to receive eight cycles of 5-fluorouracil, doxorubicin (Adriamycin), and cyclophosphamide (FAC). Patients were stratified by stage and randomly assigned to receive two cycles of high-dose cyclophosphamide, etoposide, and cisplatin with autologous hematopoietic stem cell support or no additional chemotherapy. Tamoxifen was planned for postmenopausal patients with estrogen receptor-positive tumors and chest wall radiotherapy was planned for all. All P values are from two-sided tests. RESULTS: Seventy-eight patients (48 after primary surgery and 30 after primary chemotherapy) were registered. Thirty-nine patients were randomly assigned to FAC and 39 to FAC followed by high-dose chemotherapy. After a median follow-up of 6.5 years, there have been 41 relapses. In intention-to-treat analyses, estimated 3-year relapse-free survival rates were 62% and 48% for FAC and FAC/high-dose chemotherapy, respectively (P =.35), and 3-year survival rates were 77% and 58%, respectively (P =.23). Overall, there was greater and more frequent morbidity associated with high-dose chemotherapy than with FAC; there was one septic death associated with high-dose chemotherapy. CONCLUSIONS: No relapse-free or overall survival advantage was associated with the use of high-dose chemotherapy, and morbidity was increased with its use. Thus, high-dose chemotherapy is not indicated outside a clinical trial.

Pathological assessment of response to induction chemotherapy in breast cancer.

Macroscopic and microscopic pathology review was used to assess the degree of tumor reduction after preoperative chemotherapy in 90 patients with inflammatory and locally advanced breast cancer. Fifteen (17%) patients had no evident residual macroscopic tumor on gross pathological examination, and 6 of these 15 had no residual tumor on microscopic review either. There was no significant difference in disease-free and overall survival between the six patients with no microscopic disease and the nine patients with only microscopic residual disease but no residual macroscopic tumor. These 15 patients with major reduction after induction chemotherapy had a longer disease-free survival (DFS) (median not reached at 5 yr) than the other 75 patients with lesser degrees of tumor reduction (DFS = 22 mo; P less than 0.01). Clinical evaluation of response to chemotherapy was a less accurate predictor of outcome than was the pathological assessment of response. Complete clinical responders had a 4-yr DFS of 55%, whereas patients with non macroscopic residual tumor following preoperative chemotherapy, less than one-half of whom had been judged to be a complete clinical responder, had a median DFS of greater than 60 mo and a 4-yr DFS of 75%. Patients whose mastectomy specimen had no macroscopic residual disease had a 93% 5-yr survival compared to patients with a less marked response to therapy who had a 5-yr survival of 30% (P less than 0.01). No pretreatment patient or tumor-related variables correlated with the degree of tumor reduction following preoperative therapy. Achievement of a mastectomy specimen free of residual macroscopic tumor after preoperative chemotherapy is an excellent prognostic factor for a prolonged DFS and survival. This information should be considered in the selection of postoperative systemic therapy.

Charge state breeding experiences and plans at TRIUMF.

At the Isotope Separation and ACceleration (ISAC) facility at TRIUMF, an electron cyclotron resonance ion source (ECRIS) has been set up for the charge state breeding of radioactive ions. In order to reduce background from stable ions generated in the ECRIS, several measures, including changing materials for the plasma chamber and the surrounding components, have been implemented. Further reduction has been achieved by using the post-accelerator chain as a mass filter. Since the implementation of those measures in 2013, physics experiments with accelerated radioactive isotopes of Rb, Sr, K, and Mg have been performed. In most cases, a charge breeding efficiency of several percent has been achieved. With the planned expansion of the isotope production capabilities at TRIUMF within the Advanced Rare IsotopE Laboratory project, two new target stations, one using photo-fission induced by a high-power electron beam at 50 MeV and the other one using 480 MeV protons as at ISAC, will be put into operation within the next 5 yr. Additionally, a new electron beam ion source (EBIS) based charge state breeding system will be installed. Background from such a source is expected to be much lower. The drawback is that for the efficient operation of such a system, pulsed beam operation is required, which makes the installation of an additional ion buncher in front of the EBIS necessary.

Long-term results of combined-modality therapy for locally advanced breast cancer with ipsilateral supraclavicular metastases: The University of Texas M.D. Anderson Cancer Center experience.

PURPOSE: To determine outcomes in local-regional control, disease-free survival, and overall survival in patients with locally advanced breast cancer (LABC) who present with ipsilateral supraclavicular metastases and who are treated with combined-modality therapy. PATIENTS AND METHODS: Seventy patients with regional stage IV LABC, which is defined by our institution as LABC with ipsilateral supraclavicular adenopathy without evidence of distant disease, received treatment on three prospective trials of neoadjuvant chemotherapy. All patients received neoadjuvant chemotherapy with cyclophosphamide, doxorubicin, and fluorouracil, or cyclophosphamide, doxorubicin, vincristine, and prednisone. Patients then received local therapy that consisted of either total mastectomy and axillary lymph node dissection (ALND) or segmental mastectomy and ALND before or after irradiation. Patients with no response to neoadjuvant chemotherapy were treated with surgery and/or radiotherapy. After completion of local therapy, chemotherapy was continued for four to 15 cycles, followed by radiotherapy. Patients older than 50 years who had estrogen receptor-positive tumors received tamoxifen for 5 years. RESULTS: Median follow-up was 11.6 years (range, 4.8 to 22.6 years). Disease-free survival rates at 5 and 10 years were 34% and 32%, respectively. The median disease-free survival was 1.9 years. Overall survival rates at 5 and 10 years were 41% and 31%, respectively. The median overall survival was 3.5 years. The overall response rate (partial and complete responses) to induction chemotherapy was 89%. No treatment-related deaths occurred. CONCLUSION: Patients with ipsilateral supraclavicular metastases but no other evidence of distant metastases warrant therapy administered with curative intent, ie, combined-modality therapy consisting of chemotherapy, surgery, and radiotherapy. Patients with ipsilateral supraclavicular metastases should be included in the stage IIIB category of the tumor-node-metastasis classification because their clinical course and prognosis are similar to those of patients with stage IIIB LABC.

Adjuvant therapy with escalating doses of doxorubicin and cyclophosphamide with or without leukocyte alpha-interferon for stage II or III breast cancer.

PURPOSE: A prospective study in breast cancer patients was undertaken to determine whether escalating doses of doxorubicin and cyclophosphamide would result in a higher fraction of patients free of disease, and to evaluate the role of leukocyte alpha-interferon. PATIENTS AND METHODS: Between 1982 and 1986, 319 consecutive patients with stage II or III breast cancer with one or more positive nodes were assigned randomly to receive adjuvant chemotherapy that consisted of escalating doses of doxorubicin and cyclophosphamide in combination with vincristine and prednisone or the same chemotherapy regimen followed by 1 year of leukocyte alpha-interferon. Doxorubicin was administered by 72-hour continuous infusion through a central venous catheter (maximum total cumulative dose, 430 mg/m2). All patients with positive or unknown estrogen receptor status were also given tamoxifen for 1 year. RESULTS: The median follow-up was 71 months (range, 35 to 99 months). Correlation of disease-free survival (DFS) with dose-intensity of cyclophosphamide and doxorubicin showed no improvement in DFS for patients who were able to receive escalated drug doses compared with those who were not. Doxorubicin administered by continuous infusion was associated with a negligible risk of cardiotoxicity in this study despite the administration of higher accumulative doses than in our previous adjuvant therapy studies. The DFS rates of patients who did and those who did not receive leukocyte alpha-interferon were similar. CONCLUSIONS: In this study, there was no real evidence that higher drug dose intensity was associated with longer DFS. Leukocyte alpha-interferon as it was used in this study had no therapeutic value. Doxorubicin administered by infusion was associated with a reduced risk of cardiotoxicity.

Sentinel lymph node biopsy is accurate after neoadjuvant chemotherapy for breast cancer.

PURPOSE: Sentinel lymph node (SLN) biopsy has proved to be an accurate method for detecting nodal micrometastases in previously untreated patients with early-stage breast cancer. We investigated the accuracy of this technique for patients with more advanced breast cancer after neoadjuvant chemotherapy. PATIENTS AND METHODS: Patients with stage II or III breast cancer who had undergone doxorubicin-based neoadjuvant chemotherapy before breast surgery were eligible. Intraoperative lymphatic mapping was performed with peritumoral injections of blue dye alone or in combination with technetium-labeled sulfur colloid. All patients were offered axillary lymph node dissection. Negative sentinel and axillary nodes were subjected to additional processing with serial step sectioning and immunohistochemical staining with an anticytokeratin antibody to detect micrometastases. RESULTS: Fifty-one patients underwent SLN biopsy after neoadjuvant chemotherapy from 1994 to 1999. The SLN identification rate improved from 64.7% to 94.1%. Twenty-two (51.2%) of the 43 successfully mapped patients had positive SLNs, and in 10 of those 22 patients (45.5%), the SLN was the only positive node. Three patients had false-negative SLN biopsy; that is, the sentinel node was negative, but at least one nonsentinel node contained metastases. Additional processing revealed occult micrometastases in four patients (three in sentinel nodes and one in a nonsentinel node). CONCLUSION: SLN biopsy is accurate after neoadjuvant chemotherapy. The SLN identification improved with experience. False-negative findings occurred at a low rate throughout the series. This technique is a potential way to guide the axillary treatment of patients who are clinically node negative after neoadjuvant chemotherapy.

Prospective evaluation of paclitaxel versus combination chemotherapy with fluorouracil, doxorubicin, and cyclophosphamide as neoadjuvant therapy in patients with operable breast cancer.

PURPOSE: To compare prospectively the antitumor activity of single-agent paclitaxel to the three-drug combination of fluorouracil, doxorubicin, and cyclophosphamide (FAC) as neoadjuvant therapy in patients with operable breast cancer. PATIENTS AND METHODS: Patients with T1-3N0-1M0 disease were randomized to receive either paclitaxel (250 mg/m(2)) as 24-hour infusion or FAC in standard doses at every-3-week intervals. Each patient was treated with four cycles of preoperative chemotherapy. Clinical response and extent of residual disease in the breast and lymph nodes was assessed after four cycles of induction chemotherapy. RESULTS: A total of 174 patients were registered, and 87 were randomized to each arm of the study. Clinical response, ie, complete and partial responses, was similar in both arms of the study. Three patients in the FAC arm and one patient in the paclitaxel subgroup had progressive disease. The extent of residual disease by intent-to-treat analysis at the time of surgery was similar between the two arms of the study. CONCLUSION: The results of this prospective study demonstrated that single-agent paclitaxel as neoadjuvant therapy has significant antitumor activity, and this was clinically comparable to FAC. Similar fractions of patients had clinical complete and partial responses, and very few patients had no response to either therapy. The value of alternate non-cross-resistant therapies as used in this protocol on the clinical course of this disease would require longer follow-up.

Clinical course of breast cancer patients with complete pathologic primary tumor and axillary lymph node response to doxorubicin-based neoadjuvant chemotherapy.

PURPOSE: To assess patient and tumor characteristics associated with a complete pathologic response (pCR) in both the breast and axillary lymph node specimens and the outcome of patients found to have a pCR after neoadjuvant chemotherapy for locally advanced breast cancer (LABC). PATIENTS AND METHODS: Three hundred seventy-two LABC patients received treatment in two prospective neoadjuvant trials using four cycles of doxorubicin-containing chemotherapy. Patients had a total mastectomy with axillary dissection or segmental mastectomy and axillary dissection followed by four or more cycles of additional chemotherapy. Patients then received irradiation treatment of the chest-wall or breast and regional lymphatics. Median follow-up was 58 months (range, 8 to 99 months). RESULTS: The initial nodal status, age, and stage distribution of patients with a pCR were not significantly different from those of patients with less than a pCR (P>.05). Patients with a pCR had initial tumors that were more likely to be estrogen receptor (ER)-negative (P<.01), and anaplastic (P = .01) but of smaller size (P<.01) than those of patients with less than a pCR. Upon multivariate analysis, the effects of ER status and nuclear grade were independent of initial tumor size. Sixteen percent of the patients in this study (n = 60) had a pathologic complete primary tumor response. Twelve percent of patients (n = 43) had no microscopic evidence of invasive cancer in their breast and axillary specimens. A pathologic complete primary tumor response was predictive of a complete axillary lymph node response (P<.01 ). The 5-year overall and disease-free survival rates were significantly higher in the group who had a pCR (89% and 87%, respectively) than in the group who had less than a pCR (64% and 58%, respectively; P<.01). CONCLUSION: Neoadjuvant chemotherapy has the capacity to completely clear the breast and axillary lymph nodes of invasive tumor before surgery. Patients with LABC who have a pCR in the breast and axillary nodes have a significantly improved disease-free survival rate. However, a pCR does not entirely eliminate recurrence. Further efforts should focus on elucidating the molecular mechanisms associated with this response.

Prospective randomized trial of paclitaxel alone versus 5-fluorouracil/doxorubicin/cyclophosphamide as induction therapy in patients with operable breast cancer.

The objective of this study was to compare the antitumor activity of single-agent paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) with that of the 5-fluorouracil/doxorubicin/cyclophosphamide (FAC) combination by evaluating the extent of residual disease in the breast and regional lymph nodes of patients with breast cancer following four cycles of induction chemotherapy. Patients with histologically confirmed invasive but noninflammatory carcinoma of the breast stages T2-3, N0-1, M0 were eligible to enter the study. Patients were treated with four cycles of either FAC or single-agent paclitaxel before local therapy. Following local therapy, treatment of the two arms was identical. Of 104 operable breast cancer patients who were treated with either regimen, 78 were evaluable for response to preoperative chemotherapy and had undergone local therapy. Age, TNM classification, and estrogen receptor status of the patients were similar in the two groups. Following induction chemotherapy, the extent of disease in the breast and the distribution and number of positive nodes were similar between the two treatment arms. Disease progressed in two patients in the FAC arm and in none in the paclitaxel arm during the induction phase of therapy. A higher fraction of patients had neutropenic fever during the paclitaxel treatment. Initial data from this ongoing randomized study show that paclitaxel alone has comparable anticancer activity with FAC in patients with early breast cancer. The degree of cytoreduction was similar with both induction therapies.

The role of limited surgery with irradiation in primary treatment of ductal in situ breast cancer.

The results of management of ductal carcinoma in situ with limited surgery and radiotherapy are presented at a median follow-up of 92 months. In 44 treated breasts the actuarial 10-year loco-regional control rate was 91%, four patients having recurred. Each loco-regional failure was due to invasive carcinoma and three of the affected patients have developed metastases. No patient developed metastases without previous clinically-evident invasive loco-regional disease. The 10-year disease-specific survival rate was 96%. Previous publications have shown that the 25% or greater risk of local failure after limited excision of ductal carcinoma in situ can be reduced by irradiation of the breast. Our results demonstrate that good loco-regional control is maintained in the longer term.

Primary chemotherapy for early and advanced breast cancer.

While locally advanced breast cancer (LABC) represents a small fraction of patients with breast cancer in industrialized nations, in developing countries it might constitute up to 50% of incident cases. The definition includes patients with stage IIB, III, and some with limited stage IV breast cancer. Inflammatory breast cancer (IBC) is part of LABC, but it is often reported separately, because of its dismal prognosis. LABC can be considered technically operable (stage II and IIIA), or inoperable (stage IIIB, IV and IBC). For the last two decades, patients with inoperable LABC and IBC have been treated with increasing frequency with systemic therapy first, followed by regional therapy, either surgical resection or radiotherapy. Most treatment programs also included adjuvant systemic therapy. The majority of patients with LABC and IBC respond to primary chemotherapy, and most can be rendered disease-free initially. Local control rates exceed 80% with modern combined-modality treatment strategies. Since most tumors are downstaged, some patients can be treated with breast-conserving treatments. The optimal sequence of local and systemic treatments has not been defined. Combined-modality therapies improve the treatment and the outcome for patients with LABC. Whether the sequence of utilization of various treatments influences outcome remains to be established. The administration of systemic therapies first also provides a useful biological model to assess the effects of systemic treatments on the primary tumor and regional metastases, since these are available for serial non-invasive evaluation and sampling of tumor tissue.

Ductal carcinoma in situ treated with lumpectomy and irradiation: histopathological analysis of 49 specimens with emphasis on risk factors and long term results.

Forty-nine women with ductal carcinoma in situ (DCIS) treated with lumpectomy and irradiation were studied retrospectively. The median age was 50 years (range, 29 to 73 years) and the median follow-up time from initiation of therapy was 86 months (range, 17 to 230 months). Twelve patients presented with palpable masses (0.4 to 4 cm), three with breast thickening, and three with nipple discharge. In 31 patients the tumors were detected by mammography. Intraoperatively, excision of lesions was confirmed by specimen x-ray (38 specimens) or gross inspection (five specimens) and was recorded to be complete. No record was available in the other six patients. Margins of excision free of DCIS were microscopically confirmed in 25 specimens. The size of impalpable DCIS lesions recorded in 25 patients ranged from 0.4 to 5.0 cm (mean, 1.5 cm). Using Lagios' classification system, there were 18 classic comedocarcinomas, high nuclear grade (NG) with necrosis; seven cribriform/papillary, high NG with necrosis; 17 cribriform/micropapillary, intermediate NG with or without necrosis; and seven cribriform/micropapillary, low NG without necrosis. In two patients residual malignant calcifications were present on the postoperative mammogram. Disease recurred in the treated breast at the site of incision in five patients at 18 months and 8, 11, and 12 (two patients) years from initial therapy. The rate of local disease recurrence was 2% at 5 years and 6% at 10 years; three recurrences showed invasive ductal carcinoma and two were DCIS. To evaluate risk factors the following characteristics were considered: necrosis, NG, histological type, periductal fibrosis, periductal lymphoid infiltrate, margin status, age, and method of tumor detection. The end points chosen were recurrence and death from any cause (because only one patient died of disease). Although the recurrences were attributed to residual disease in two patients, of the clinical and pathological parameters evaluated, only periductal fibrosis showed a significant relationship with outcome, with a P value < or = .05 by the Wilcoxon test. On the other hand, using the proportional hazards model, necrosis was a significant predictor for recurrence (P = .02), as was the pair fibrosis and tumor detection when taken together (P = .05). Fibrosis significantly associated with high NG, Lagios' histological subtypes I and II, periductal lymphoid infiltrate, and necrosis (P < or = .0006).(ABSTRACT TRUNCATED AT 400 WORDS)

The effects of Cannabis sativa on the behavior of adult female chacma baboons (Papio ursinus) in captivity.

Indices of locomotory and social activity were quantified during 102 h of daily tests with two pairs of baboons under three conditions: baseline, cannabis administration, and postdrug withdrawal. Six percent of whole dried plants of cannabis (33 g) was incorporated into the daily feed. In one pair, social activity increased during cannabis administration, with no clear effect on locomotory behavior. In the second pair locomotory activity decreased, but there was no consistent change in social interaction. Thus individuals responded differently to the drug, and the social environment of each pair appeared to be implicated as a determining factor.

Breast cancer in 3,558 women: age as a significant determinant in the rate of dying and causes of death.

The forces of mortality created by cancer of the breast have been examined utilizing data collected during the past 19 years by the Syracuse, N. Y., Upstate Medical Center Cancer Registry on 3,558 women. Except for 15 lost to follow-up, all have been contacted annually through 1974 or until death. Time and cause were recorded for all deaths. In April, 1975, 1,883 remain alive and in the registry and 1,660 women have died. Using life-table analyses and considering deaths due only to breast cancer, mortality rates were calculated for three age groups--21 to 50 years, 51 to 70 years, and 71 to 100 years. Breast cancer expresses its lethality most vigorously in the oldest group. The half-death time (50% mortality rate) for the youngest group was 13 years, for the middle group 8 years, and for the oldest group 5 years. The rate of dying was a function of both age and stage at diagnosis. At 16 to 18 years after diagnosis, deaths due to breast cancer begin to disappear. Eighty-eight percent of the women who died following a diagnosis of cancer of the breast have died of their breast cancer. Age as well as stage at diagnosis are significant determinants on the length of survival and cause of death.

Squamous cell carcinoma arising in previously burned or irradiated skin.

Squamous cell carcinoma (SCC) arising in previously burned or irradiated skin was reviewed in 66 patients treated between 1944 and 1986. Healing of the initial injury was complicated in 70% of patients. Mean interval from initial injury to diagnosis of SCC was 37 years. The overwhelming majority of patients presented with a chronic intractable ulcer in previously injured skin. The regional relapse rate after surgical excision was very high, 58% of all patients. Predominant patterns of recurrence were in local skin and regional lymph nodes (93% of recurrences). Survival rates at 5, 10, and 20 years were 52%, 34%, and 23%, respectively. Five-year survival rates in previously burned and irradiated patients were not significantly different (53% and 50%, respectively). This review, one of the largest reported series, better defines SCC arising in previously burned or irradiated skin as a locally aggressive disease that is distinct from SCC arising in sunlight-damaged skin. An increased awareness of the significance of chronic ulceration in scar tissue may allow earlier diagnosis. Regional disease control and survival depend on surgical resection of all known disease and may require radical lymph node dissection or amputation.