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Since the discovery of x-rays and radioactivity, the radiotherapeutic management of malignancy has seen numerous spectacular improvements. Beside the widely used photons and electrons, one area of particular interest is the development and refinement of what has become known as "new particles". In this paper we give a brief outline of the properties of such particles and catalogue the impact these have made on the clinical outcome.
The potential of heavy ion therapy for clinical use in cancer therapy stems from the biological parameters of heavy charged particles and their precise dose localization. Biologically, carbon, neon, and other heavy ion beams (up to about silicon) are clinically useful in overcoming the radioresistance of hypoxic tumors, thus increasing the biological effectiveness relative to low linear energy transfer x-ray or electron beams. Cells irradiated by heavy ions show less variation in cell-cycle-related radiosensitivity and decreased repair of radiation injury. The physical parameters of these heavy charged particles allow precise delivery of high doses to tumors while minimizing irradiation of normal tissues. Clinical use requires a close interaction between radiation oncologists, medical physicists, accelerator physicists, engineers, computer scientists, and radiation biologists.
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We have reviewed the incidence of cisplatin-induced anaemia in patients affected with solid tumours treated with at least three courses of first-line cisplatin-containing regimens. In our experience, a low percentage (5%) of patients required transfusions of red blood cells. We think it is of the utmost importance to adopt uniform criteria in monitoring and treatment of patients at risk of developing cisplatin anaemia and to identify subsets of patients to eventually treat with erythropoietin.
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In registry-based population studies on marital status in relation to cancer, incidence rates sometimes have been calculated using marital status-specific populations that have been estimated by interpolation and extrapolation from census data as a denominator. Alternatively, other cancers from the same registry have been used to estimate the proportion of the population in each marital-status category in the calculation of the relative risk (RR) of a given cancer. Using cancer registry data from four United States populations for the years 1979-87, we compared the relative incidence estimated using each of the two methods. For selected cancers diagnosed during 1979-81, the age-adjusted risks of never-married Black persons were 1.5 to 2.2 times those of married persons when the population size was estimated from census data. The corresponding RRs were 0.7 to 1.1 when the 'control' cancers were used. Among Whites, the differences between the two methods were about 20 to 30 percent. For both races, the difference between the methods was greater still for the years for which we relied on extrapolation to estimate the population (1981-87). The differences between the risk estimates from the two methods may be related to underenumeration in the census, inconsistent definitions of marital status between cancer registries and the census, errors in the extrapolation of the population, and/or the possible association of the incidence of 'control' cancers with marital status. In the US, while each method has some potential for bias, we believe that the likelihood of bias is relatively greater using the census-based method.
The age-standardized annual mortality rates for 1969/72 are analyzed for each of 183 districts which have been characterized socio-economically and demographically on the basis of the 1970 census. Discriminant analysis for several malignant tumours shows increased mortality in regions of greater population density (lung cancer) and, independently of this finding, in regions with a higher proportion of persons working in the "tertiary sector" (other malignant tumours).
Ribonucleotide reductase (RR) is a key regulatory enzyme in the DNA synthesis pathway and is the target of the cancer chemotherapeutic agent hydroxyurea. The study of RR is significantly hindered by the tedious and labor-intensive nature of enzymatic assay. In this report, we present a novel RR assay in which detection of the deoxyribonucleotides produced by RR occurs via coupling to the DNA polymerase reaction, and is enhanced by using RNase to degrade endogenous RNA. Cell extracts from various cell lines were treated with RNase and then reacted with ATP and radioactive ribonucleotide diphosphate as the substrate. Incorporation of the radioactive substrate [14C]CDP into DNA was linear over 30 min and was linear with the amount of extract, which provided RR activity. The reaction was inhibited by hydroxyurea and required Mg2+ and ATP, suggesting that the assay is specific to RR activity. While RR activities determined by our method and by a conventional method were comparable, this novel method proved to be simpler, faster, more sensitive and less expensive. In addition, assay of the RR activity for multiple samples can easily be performed simultaneously. It is superior to other RR assays in all aspects.
Suprapubic transabdominal prostatic sonography was performed at two Nigerian centers over the past year. All abnormal glands were found enlarged. Capsular, periprostatic and extra-organ features helped to segregate carcinomas from benign diseases. Gland shape and internal texture were less useful criteria. Prostatic sonography has great promise in developing and fragile economies, where other efficacious and contemporary imaging modalities are unaffordable.
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MRI, because of its multiplaner capability and high soft tissue contrast, is ideally suited for examination of the prostate. The normal prostatic zonal architecture and periprostatic anatomy can be visualized. The use of an endorectal surface coil greatly enhances resolution. Clinical application to the study of BPH, prostate carcinoma, prostatic cysts, and inflammatory disease is discussed. MRI appears to be emerging as the modality of choice for imaging the prostate.
Although there is good evidence that carcinomas of the prostate are usually seen as echopenic masses within the external zone of the prostate, it is unclear how often an echopenic mass has an origin other than carcinoma of the prostate. Technical problems at the periphery of the gland not uncommonly create echopenic areas on an artifactual basis. Whether ultrasound will prove to be a satisfactory screening method for the detection of carcinoma of the prostate is yet to be decided. Prospective studies are in progress, but it has not yet been established whether prostate screening is a worthwhile procedure. The best possible equipment is required to detect these subtle lesions; cheap equipment will probably not give adequate results.
Systematic random rectal ultrasound directed map-biopsy of the prostate was performed in 77 RDE (rectal digital examination) positive and 25 RDE negative cases, if applicable. Hypoechoic areas were found in 30% of RDE positive and in 16% of RDE negative cases. The score for carcinoma in the hypoechoic areas was 6.5% in RDE positive and 0% in RDE negative cases, whereas systematic map biopsy detected 62% carcinomas in RDE positive, and 16% carcinomas in RDE negative patients. The probability of positive diagnosis of prostate carcinoma increased in parallel with the number of biopsy samples/case. The importance of systematic map biopsy is emphasized.
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