Cardiac-sparing radiotherapy for locally advanced non-small cell lung cancer

BACKGROUND

We have carried out a study to determine the scope for reducing heart doses in photon beam radiotherapy of locally advanced non-small cell lung cancer (LA-NSCLC).

MATERIALS AND METHODS

Baseline VMAT plans were created for 20 LA-NSCLC patients following the IDEAL-CRT isotoxic protocol, and were re-optimized after adding an objective limiting heart mean dose (MDHeart). Reductions in MDHeart achievable without breaching limits on target coverage or normal tissue irradiation were determined. The process was repeated for objectives limiting the heart volume receiving ≥ 50 Gy (VHeart-50-Gy) and left atrial wall volume receiving ≥ 63 Gy (VLAwall-63-Gy).

RESULTS

Following re-optimization, mean MDHeart, VHeart-50-Gy and VLAwall-63-Gy values fell by 4.8 Gy and 2.2% and 2.4% absolute respectively. On the basis of associations observed between survival and cardiac irradiation in an independent dataset, the purposefully-achieved reduction in MDHeart is expected to lead to the largest improvement in overall survival. It also led to useful knock-on reductions in many measures of cardiac irradiation including VHeart-50-Gy and VLAwall-63-Gy, providing some insurance against survival being more strongly related to these measures than to MDHeart. The predicted hazard ratio (HR) for death corresponding to the purposefully-achieved mean reduction in MDHeart was 0.806, according to which a randomized trial would require 1140 patients to test improved survival with 0.05 significance and 80% power. In patients whose baseline MDHeart values exceeded the median value in a published series, the average MDHeart reduction was particularly large, 8.8 Gy. The corresponding predicted HR is potentially testable in trials recruiting 359 patients enriched for greater MDHeart values.

CONCLUSIONS

Cardiac irradiation in RT of LA-NSCLC can be reduced substantially. Of the measures studied, reduction of MDHeart led to the greatest predicted increase in survival, and to useful knock-on reductions in other cardiac irradiation measures reported to be associated with survival. Potential improvements in survival can be trialled more efficiently in a population enriched for patients with greater baseline MDHeart levels, for whom larger reductions in heart doses can be achieved.

The use of chlorhexidine to reduce maternal and neonatal mortality and morbidity in low-resource settings

Of the 4 million neonatal deaths and 500,000 maternal deaths that occur annually worldwide, almost 99% are in developing countries and one-third are associated with infections. Implementation of proven interventions and targeted research on a select number of promising high-impact preventative and curative interventions are essential to achieve Millennium Development Goals for reduction of child and maternal mortality. Feasible, simple, low-cost interventions have the potential to significantly reduce the mortality and severe morbidity associated with infection in these settings. Studies of chlorhexidine in developing countries have focused on three primary uses: 1) intrapartum vaginal and neonatal wiping, 2) neonatal wiping alone, and 3) umbilical cord cleansing. A study of vaginal wiping and neonatal skin cleansing with chlorhexidine, conducted in Malawi in the 1990s suggested that chlorhexidine has potential to reduce neonatal infectious morbidity and mortality. A recent trial of cord cleansing conducted in Nepal also demonstrated benefit. Although studies have shown promise, widespread acceptance and implementation of chlorhexidine use has not yet occurred. This paper is derived in part from data presented at a conference on the use of chlorhexidine in developing countries and reviews the available evidence related to chlorhexidine use to reduce mortality and severe morbidity due to infections in mothers and neonates in low-resource settings. It also summarizes issues related to programmatic implementation.

Seroprevalence of human herpesvirus-8 (HHV-8) in countries of Southeast Asia compared to the USA, the Caribbean and Africa

Seroprevalence of HHV-8 has been studied in Malaysia, India, Sri Lanka, Thailand, Trinidad, Jamaica and the USA, in both healthy individuals and those infected with HIV. Seroprevalence was found to be low in these countries in both the healthy and the HIV-infected populations. This correlates with the fact that hardly any AIDS-related Kaposi's sarcoma has been reported in these countries. In contrast, the African countries of Ghana, Uganda and Zambia showed high seroprevalences in both healthy and HIV-infected populations. This suggests that human herpes virus-8 (HHV-8) may be either a recently introduced virus or one that has extremely low infectivity. Nasopharyngeal and oral carcinoma patients from Malaysia, Hong Kong and Sri Lanka who have very high EBV titres show that only 3/82 (3.7%) have antibody to HHV-8, demonstrating that there is little, if any, cross-reactivity between antibodies to these two gamma viruses.

Rapid telomere shortening in children

Telomere shortening may reflect the total number of divisions experienced by a somatic cell and is associated with replicative senescence. We found that the average rate of telomere shortening in peripheral blood mononuclear cells (PBMCs) obtained longitudinally from nine different infants during the first 3 years of life (270 bp per year) is more than fourfold higher than in adults and does not correlate with telomerase activity. These results show that the rate of telomere loss changes during ontogeny, suggesting the existence of periods of accelerated cell division. Because human immunodeficiency virus (HIV) preferentially infects actively dividing cells, our observation suggesting accelerated cell division in children may provide an explanation for some of the distinctive pathogenic features of the HIV disease in infants, including higher viral loads and more rapid progression to acquired immunodeficiency syndrome (AIDS).

Intrathecal chemoprophylaxis in the prevention of central nervous system relapse in Burkitt's lymphoma

A retrospective review of patients treated for endemic Burkitt's lymphoma in Ghana was undertaken to evaluate the efficacy of intrathecal (IT) chemoprophylaxis in preventing central nervous system (CNS) relapse. Patients treated before 1974 received no IT chemoprophylaxis and those treated between 1974 and 1979 received IT methotrexate in addition to systemic chemotherapy. In patients presenting with facial disease only (Stages I-II), there was no significant difference in the frequency of CNS relapse between those receiving IT chemoprophylaxis and those not receiving any. CNS relapse was, however, significantly reduced in patients presenting with abdominal disease (Stage III) who received IT chemoprophylaxis in addition to systemic combination therapy. This was associated with an improved survival.

Utilization and expenditures for ambulatory medical care by people hospitalized: United States, 1980

The National Medical Care Utilization and Expenditure Survey was conducted throughout 1980 to collect information on health, access to and use of medical services, associated charges and sources of payment, and health insurance coverage. The survey was based on a probability sample of about 6,600 households and 17,123 people representative of the civilian noninstitutionalized population of the United States. This report is one of a series of descriptive reports based on data from the National Medical Care Utilization and Expenditure Survey. It characterizes the population by hospital utilization and certain sociodemographic and health variables, and shows how hospitalization effects the use and cost of ambulatory medical care. The following are some of the highlights of the report. Almost everyone was covered by some form of health insurance at some time during 1980. Only 7.6 percent were not covered at all, and 10 percent had insurance only part of the year. The proportion not covered at all varied according to the number of times hospitalized, ranging from 8.2 percent for people not hospitalized during the year to 1.8 percent for people hospitalized three or more times. People with one or more hospital stays during 1980 had a physician visit rate greater than three times that for people not hospitalized. Similarly, the expenditures for ambulatory medical care for people experiencing hospitalizations was almost nine times that for people were not hospitalized during the year. The rate of physician visits is much larger immediately prior to hospital admission or immediately after discharge than it is at other times. About 40 percent of all physician visits during the year occurred within a month before admission and after discharge. within a month before admission and after discharge.

Human T-cell leukemia virus (HTLV-I) antibodies in Africa

Antibodies specific for human T-cell leukemia-lymphoma virus type I (HTLV-I) were demonstrated in serum samples from various groups of people in South Africa, Uganda, Ghana, Nigeria, Tunisia, and Egypt. The samples had been collected for other purposes and were presumably selected without bias toward clinical conditions associated with HTLV infections. Regional differences in antibody positivity were observed, indicating widely distributed loci of occurrence of HTLV on the African continent in people of both black and white ancestry. Two patients with high titers of antibody to HTLV-I had some signs of adult T-cell leukemia-lymphoma. In several groups a high frequency of false positive serum reactions was indicated when specific confirmation steps were included in the assay. Further characterization of these sera revealed highly elevated immunoglobulin levels, possibly due to polyclonal activation of immunoglobulin synthesis in these subjects. The possibility that related cross-reactive human retroviruses coexist in the same groups was not eliminated.

Endothelial cell pavement pattern in the pulmonary trunk in rats in chronic hypoxia

Right ventricular hypertrophy, and by inference pulmonary arterial hypertension, were induced in female Wistar Albino rats by subjecting them to a barometric pressure of 380 mmHg for four weeks. A control group was kept at normal barometric pressure for a similar period of time. The cell boundaries of the endothelial lining of the aorta, pulmonary trunk and inferior vena cava were stained in situ by a modified silver method of Poole et al. (1958). Photomicrographs of the intimal surfaces of these blood vessels at a standard magnification were used to determine the length, breadth and area of the cells. In the control rats the endothelial cells were found to have a characteristic shape and size in each of the three vessels studied. Those of the aorta were small and elongated in the direction of blood flow with tapering ends. The endothelial cells of the inferior vena cava were rectangular. Those of the pulmonary trunk were polygonal and had tessellated borders. In the test rats with right ventricular hypertrophy induced by chronic hypoxia the endothelial cell pavement pattern of the pulmonary trunk changed to resemble that of the aorta. It is considered that this was an expression of the acquired pulmonary hypertension, the fusiform shape appearing appropriate for an elevated pressure.

Pulmonary endothelial pavement patterns

The appearance of the endothelial pavement pattern was studied in the pulmonary trunk, pulmonary veins, aorta, and inferior vena cava of the rat by means of silver staining of the cell borders. The endothelial cell in each of the four blood vessels was found to have its own distinctive shape, fusiform and pointed in the direction of blood flow in the case of the aorta and larger and more rectangular in the pulmonary trunk and pulmonary veins. Detailed quantitation of the dimensions and surface area of the endothelial cells in each blood vessel was carried out by a photographic technique. Pulmonary hypertension was induced in one group of rats by feeding them on Crotalaria spectabilis seeds. The endothelial pavement pattern in their pulmonary trunks became disrupted with many of the cells assuming a fusiform shape reminiscent of aortic endothelium. Many small, new endothelial cells formed in the pulmonary trunk suggesting division of cells to line the enlarging blood vessels. In contrast the endothelial cells of the inferior vena cava merely increased in size to cope with the dilatation of this vein.

Clara cells in llamas born and living at high and low altitudes

Quantitative histological studies showed greater Clara cell activity in two llamas born and spending their lives in the High Andes as compared to a llama born and spending its life at sea level.

Sequential evaluation of cutaneous delayed hypersensitivity responses to recall and to lymphoid cell line antigens in Burkitt's lymphoma

Delayed cutaneous hypersensitivity reactions to standard recall antigens (candidin, mumps and PPD), to crude membrane extracts of a cell line derived from Burkitt's lymphoma (Raji) and to cell line derived from normal lymphocytes (F265) were sequentially evaluated in 44 patients with Burkitt's lymphoma. Sixteen patients (36%) manifested delayed hypersensitivity responses to the standard antigens and seven (16%) to the Raji membrane extract at presentation. Following successful chemotherapy, there was prompt and significant improvement of reactivity to both the standard and Raji antigens (p greater than 0.001), suggesting that the initial impairment of delayed hypersensitivity was most likely related to tumor burden. By 9 months after treatment, all patients in sustained remission expressed reactivity to Raji and 21 of 22 to the standard antigens. None of the patients skin-tested with the F265 extract at presentation gave a positive response and only one subsequently expressed reactivity after remission was induced. On relapse, reactivity to the standard antigens was more readily lost (4 of 11) then reactivity to the Raji extract (1 of 7). Pretreatment delayed hypersensitivity to the standard antigens also correlated better with long-term survival than to pretreatment responses to Raji. It remains to be determined whether the antigens expressed in the Raji extract are indeed tumor-specific or related to Epstein-Barr virus.

Respiratory syncytial virus infections within families

To examine intrafamily spread of respiratory syncytial virus infections and their associated illnesses, 36 families with 188 members were studied during an outbreak of such infections. Nurses visited every three to four days to obtain specimens for viral isolation and interview household members. The virus infected 44.4 per cent of families, and 21.9 per cent of all members. All age groups had appreciable attack rates (with a range of 16.8 per cent in adults to 29.4 per cent in infants). In infected families, 45.9 per cent of members became infected, including 10 of 16 infants. Secondary attack rate for all ages was 27 per cent, and that for infants 45.4 per cent. An infant's older sibling appeared most likely to introduce the virus into the family. Associated acute respiratory illnesses occurred in 94.9 per cent of cases, and appeared more severe than those not associated with respiratory syncytial virus. When the virus was introduced into a family the high attack rate produced an illness of age-related severity.