Anemia during sequential induction chemotherapy and chemoradiation for head and neck cancer: the impact of blood transfusion on treatment outcome.

PURPOSE: Sequential treatment (chemotherapy followed by concomitant chemoradiation; CCRT) is increasingly being used for radical treatment of squamous cell cancer of the head and neck (SCCHN), which results in increased myelosuppression. In this study, we review the incidence of anemia and the effect of a policy of hemoglobin (Hb) maintenance by blood transfusion on disease outcomes in these patients. METHODS AND MATERIALS: Retrospective review of the records of patients with SCCHN treated with sequential CCRT formed the basis of this study. The incidence of anemia and statistics on blood transfusion were documented. For the purpose of outcome analyses, patients were divided into four categories by (1) transfusion status, (2) nadir Hb concentration, (3) number of transfusion episodes, and (4) number of units of blood transfused (NOUT). Data on 3-year locoregional control (LRC), relapse-free survival (RFS), disease-specific survival (DSS), and overall survival (OS) were analyzed. RESULTS: One hundred and sixty-nine patients were identified. The median follow-up was 23.6 months. The RFS (52% vs. 41%, p = 0.03), DSS (71% vs. 66%, p = 0.02), and OS (58% vs. 42% p = 0.005) were significantly better for patients who did not have a transfusion vs. those who did. The LRC, RFS, DSS, and OS were also significantly better for patients with nadir Hb level >12 vs. <12 g/dL and NOUT 1-4 vs. >4. CONCLUSION: Our study seems to suggest that blood transfusion during radical treatment for SCCHN might be detrimental. Further research should be undertaken into the complex interactions among tumor hypoxia, anemia, and the treatment of anemia before making treatment recommendations.

Circular dichroism spectra of human hemoglobin reveal a reversible structural transition at body temperature.

Previously we have shown that human red blood cells (RBCs) undergo a sudden change from blocking to passing through a 1.3+/-0.2-microm micropipette when applying an aspiration pressure of 2.3 kPa at a critical transition temperature (Tc = 36.4+/-0.3 degrees C). Low-shear viscosity measurements suggested that changes in the molecular properties of hemoglobin might be responsible for this effect. To evaluate structural changes in hemoglobin at the critical temperature, we have used circular dichroism (CD) spectroscopy. The thermal denaturation curves of human hemoglobin A (HbA) and hemoglobin S (HbS) upon heating between 25 and 60 degrees C were non-linear and showed accelerated denaturation between 35 and 39 degrees C with a midpoint at 37.2+/-0.6 degrees C. The transition was reversible below 39 degrees C and independent of solution pH (pH 6.8-7.8). It was also independent of the oxygenation state of hemoglobin, since a sample that was extensively deoxygenated with N2 showed a similar transition by CD. These findings suggest that a structural change in hemoglobin may enable the cellular passage phenomenon as well as the temperature-dependent decrease in viscosity of RBC solutions.

Alteration of radiation-induced hematotoxicity by amifostine.

PURPOSE: To investigate whether amifostine can reduce radiation hematotoxicity. PATIENTS AND METHODS: Seventy-three patients undergoing radiotherapy for squamous cell carcinoma of the head and neck at the university clinics of Freiburg, Heidelberg, and Erlangen were evaluated. All received 60 Gy (50-70 Gy) at 5 x 2 Gy fractions per week employing standard techniques. Thirty-five were randomized to receive 200 mg/m(2) amifostine i.v. 30 min before radiation; 38 served as control patients. Blood counts (total n = 501) were determined before, during, and while completing radiotherapy. Changes of leukocyte, platelet, and hemoglobin levels were determined and compared using the t test. RESULTS: The blood hemoglobin level and the platelet count were not affected by irradiation, for either the amifostine-treated or control patients. Similarly, the leukocyte counts of amifostine-treated patients did not change during irradiation. However, control patients experienced a decrease in leukocyte count from 8.1 x 10(3)/mm(3) to 5.8 x 10(3)/mm(3) (difference: 2.3 x 10(3)/mm(3)). This seems to be line specific: Whereas amifostine does not affect lymphocyte count, a radiation-induced decrease of neutrophil granulocytes seems to be prevented. CONCLUSION: Amifostine protects from radiation hematotoxicity, particularly affecting the granulocytopoiesis. These data confirm results from our former study.

The utility of serial complete blood count monitoring in patients receiving radiation therapy for localized prostate cancer.

PURPOSE: It is standard practice in our department to monitor weekly complete blood counts (CBCs) in patients receiving definitive radiation therapy for prostate cancer. The clinical utility and cost effectiveness of this practice has not been analyzed. METHODS AND MATERIALS: The charts of all prostate cancer patients treated with radiation therapy between January 1994 and July 1996 at the Veterans Administration Hospital, Philadelphia, PA were reviewed. CBC values were available for 89 patients. Patients received a median dose of 68 Gy using a four-field box technique and megavoltage photons. Whole-pelvic radiotherapy followed by a conedown to the prostate was administered to 29 patients. Fifty-nine patients received radiation to the prostate alone or prostate and seminal vesicles. Fifty-seven patients received concurrent hormonal therapy which included luteinizing hormone-releasing hormone (LHRH) agonist, antiandrogens, or both. RESULTS: No patient experienced a drop in their hemoglobin, white blood cells (WBCs), or platelets below critical nadirs (defined as WBC < 2 counts x 1000/mm(3), hemoglobin < 8 g/dl, platelet < 50 counts x 1000/mm(3) 2 in WBCs. In the urban area surrounding the Philadelphia Veterans Administration Medical Center, the cost of obtaining a CBC is approximately $30. However, if staff time is considered, the cost of obtaining a weekly CBC during prostate cancer radiotherapy approached $400 per patient. CONCLUSION: These results suggest that weekly monitoring of CBCs in prostate cancer patients undergoing definitive radiotherapy may not be necessary. We recommend a baseline CBC be performed, and if normal, no other monitoring unless clinically indicated. This strategy would result in a cost savings approaching $30,000 per 100 treated patients. Further research on the cost effectiveness and utility of serial blood tests in patients receiving partial body radiation therapy is needed.

A possible allosteric communication pathway identified through a resonance Raman study of four beta37 mutants of human hemoglobin A.

The highly conserved tryptophan at position beta37 occupies a key locus at the hinge region within the alpha1beta2 interface of the mammalian hemoglobins. This residue is thought to play an important role in mediating the heme-heme interaction associated with the cooperative binding of oxygen; however, its explicit function is unclear. In this study, the proximal heme environments of several beta37 mutants of adult human hemoglobin (HbA) are probed using visible (Soret band enhanced) resonance Raman spectroscopy. In the equilibrium deoxy derivatives of these mutants, a systematic variation in proximal strain, as reflected in the iron-proximal histidine (F8) stretching frequency, nu(Fe-His), is seen upon mutation of the beta37 residue. The variation in proximal strain correlates with both the ligand binding rates [Kwiatkowski et al. (1998) Biochemistry 37, 4325-4335] and conformational changes observed at the FG corner through X-ray crystallography [Kavanaugh et al. (1998) Biochemistry 37, 4358-4373]. The results from the deoxy samples indicate a plasticity of the tertiary structure within the T quaternary state. The correlation between the X-ray data and the Raman supports the idea that the proximal strain at the heme within the T state can be modulated by a combination of forces including those arising from the hinge region of the alpha1beta2 interface, from the binding of allosteric effectors, and from the degree of iron displacement from the heme plane. Each of these contributors appears to operate through a shifting of the F helix either away from or toward the FG corner. The Raman spectra obtained from the 10 ns CO photoproduct of the beta37 mutant Hb's indicate that these mutants contain an altered coupling between the R state alpha1beta2 interface and the proximal heme environment. This altered coupling could be due to either dissociation of the ligated mutant tetramers into dimers or the formation of an R state tetramer with significantly weakened hydrogen bonds and van der Waals contacts between the alpha1 and beta2 subunits at the interface. In either case, the results reveal a clear-cut structural basis for the quaternary enhancement effect in which the normal R state quaternary structure produces a higher affinity ligand binding site than that which occurs in the corresponding dimeric form of the protein. The normal R state interface is shown to be important for stabilizing a favorable ligand binding environment that persists long enough after laser photolysis to enhance the geminate rebinding process within the photoproduct. The addition of IHP to the solution of mutant COHb proteins results in photoproduct spectra that are all identical and are consistent with the ligand-bound derivatives having either a T state structure or a very strained and anomalous R state structure.

Analysis of weekly complete blood counts in patients receiving standard fractionated partial body radiation therapy.

PURPOSE: Hematopoiesis is among the most sensitive systems in the body to radiation. Routine complete blood counts (CBCs) are common in clinical radiotherapy practice. Only a few studies have attempted to characterize the behavior of peripheral blood levels during partial body radiation therapy with field sizes smaller than those used in hemibody or total nodal irradiation. Such information is needed to identify which patients are at risk for cytopenia and require close monitoring. METHODS AND MATERIALS: In 1993, 412 new patients were seen at Michael Reese Hospital for radiotherapy. A total of 972 weekly CBCs were identified for 155 patients receiving a minimum of 5 weeks of treatment for breast, prostate, lung, gynecological, or head and neck malignancies. Linear regression models were fitted to the weekly CBC values for those patients who had pretreatment CBC values recorded. Factors affecting starting levels, rates of decline, and nadirs during treatment were determined for leukocytes, platelets, and hemoglobin. RESULTS: Leukocytes declined most dramatically during the first week of treatment (16% from pretreatment to Week 1 levels) and then at a rate of 3.3% per week from Week 1 to Week 7 (p < 0.001). Total mean leukocyte decrease over 7 weeks of therapy was 30%. Platelets declined 9% on average during the first week of therapy and then at a mean rate of 1.4% per week (p < 0.02). A statistically significant decrease in hemoglobin levels could not be detected. No difference in the rate of decrease could be found for different disease sites, age groups, or amount of marrow irradiated. The effects of chemotherapy were variable, depending on blood element and whether therapy was sequential or concomitant. The odds of a nadir < 2000 counts/mm3 for white blood count (WBC), < 50,000 counts/mm3 for platelets, and < 8.0 g/dl for hemoglobin were all well below 5%. A strong correlation existed between starting CBC values and nadirs; patients with lower Week 1 CBC levels were most likely to have the lowest nadirs. CONCLUSIONS: Low CBC levels during radiation therapy are likely to be the result of other medical problems that cancer patients face. Regional irradiation with small field sizes (< 40% of total body marrow) typically used in clinical radiotherapy is unlikely to be the cause of marrow depression significant enough to warrant medical intervention. Blood levels taken during the first week of treatment (Week 1) can be used to determine risks of developing critical nadirs. Localized breast and prostate cancer patients are unlikely to require routine CBCs if initial levels are normal. Routine CBC levels on all radiation oncology patients without other reasons for hematopoietic depression requires reevaluation, as millions of dollars are spent on unnecessary testing. If weekly CBC blood levels are avoided in localized breast and prostate cancer patients, this alone could potentially result in a savings of as much as $40 million a year nationally.

Protein dynamics. Comparative investigation on heme-proteins with different physiological roles.

We report the low temperature carbon monoxide recombination kinetics after photolysis and the temperature dependence of the visible absorption spectra of the isolated alpha SH-CO and beta SH-CO subunits from human hemoglobin A in ethylene glycol/water and in glycerol/water mixtures. Kinetic measurements on sperm whale (Physeter catodon) myoglobin and previously published optical spectroscopy data on the latter protein and on human hemoglobin A, in both solvents, (Cordone, L., A. Cupane, M. Leone, E. Vitrano, and D. Bulone. 1988. J. Mol. Biol. 199:312-218) are taken as reference. Low temperature flash photolysis data are analyzed within the multiple substates model proposed by Frauenfelder and co-workers (Austin, R. H., K. W. Beeson, L. Eisenstein, H. Frauenfelder, and I. C. Gunsalus. 1975. Biochemistry. 14:5355-5373). Within this model a distribution of activation enthalpies for ligand binding accounts for the structural heterogeneity of the protein, while the preexponential factor, containing also the entropic contribution to the free energy of the process, is considered to be constant for all conformational substates. Optical spectra are deconvoluted in gaussian components and the temperature dependence of the moments of the resulting bands is analyzed, within the harmonic Frank-Condon approximation, to obtain information on the stereodynamic properties of the heme pocket. The kinetic and spectral parameters thus obtained are found to be protein dependent also with respect to their sensitivity to changes in the composition of the external medium. A close correlation between the kinetic and spectral features is observed for the proteins examined under all experimental conditions studied. The results reported are discussed in terms of differences in the heme pocket structure and in the conformational heterogeneity among the various proteins, as related to their different capability to accommodate constraints imposed by the external medium.

Selective laser ablation of venous thrombus: implications for a new approach in the treatment of pulmonary embolus.

Laser radiation was employed to ablate venous thrombus or emboli with parameters that would not injure endovascular tissues. Output from a 482-nm, 1-microsec pulsed dye laser was delivered through a 320-microns-diameter fiber to in vitro samples of fresh thrombus (T), venous or pulmonary emboli (VE), inferior vena cava (IVC), pulmonary artery (PA), pulmonary valve, and endocardium (atrial and ventricular). The mean threshold fluences for ablation of T and VE were 1.1 and 5.1 J/cm2, respectively. In contrast, the mean threshold fluences for IVC and PA were significantly higher (P less than 0.0001), at 120 and 124 J/cm2, respectively. Ablation efficiency of thrombus was in excess of 100 mg/J, under conditions that caused no histologic injury to the pulmonary artery. To correlate ablation studies with optical absorption by the tissues, optical properties of fresh T, VE, IVC, and PA were studied. Hemoglobin species accounted for the more than 10 times higher 482-nm absorption by T and VE compared to IVC and PA. This explains the differences in ablation thresholds and, thus, the selectivity encountered. These observations demonstrate, more than any other study in the vascular system, that with pulsed optical radiation, efficient laser ablation of venous thrombus is feasible with a wide margin of safety, and without damage to the surrounding vascular tissue.