Detection of atmospheric nuclear explosions: the infrasound component of the International Monitoring System

The infrasound component of the International Monitoring System (IMS') for Comprehensive Nuclear-Test-Ban Treaty verification will consist of 60 array stations distributed as uniformly as possible over the surface of the globe. This network will be far larger and more sensitive than any other previously operated infrasound network. In this paper, we discuss the design and performance characteristics of this monitoring network and the current status of the site survey and installation programs. A brief review of significant developments in infrasound monitoring technology in the last few years is also presented along with a summary of the various areas where data from this unique global network is likely to be of value to the scientific community.

Prosthetic devices within radiotherapy fields: planning implications and results

Prosthetic devices made of plastic or silicon are occasionally present in patients requiring radiotherapy (RT). The effect of RT on these devices and the potential implications of their presence on RT planning are relatively unknown. Three examples are presented in which various devices were included in RT fields. In two of the examples in vitro testing of the devices with high single doses of radiation was undertaken. Radiotherapy was given to all patients with high doses received by the devices. Minor adjustments were made to the planning techniques to reduce the doses to the devices. Neither significant complications nor any malfunctions of the devices were noted subsequently.

Validation of a malnutrition screening tool for patients receiving radiotherapy

Nutrition screening identifies individuals who are malnourished or at risk of becoming malnourished and who may benefit from nutrition support. The aim of this study was to validate a new malnutrition screening tool (MST) in cancer patients undergoing radiotherapy. The MST was compared with the subjective global assessment (SGA) of nutritional status. One hundred and six patients attending two cancer care centres in Australia were independently rated as well nourished or malnourished using SGA and at risk or not at risk of malnutrition using the MST. Convergent validity of the MST was established by determining the ability of the MST to predict SGA. According to SGA, 89% of the patients were well nourished and 11% were moderately malnourished. According to the MST, 28% of patients were at risk of malnutrition. The MST had a sensitivity of 100% and a specificity of 81%. The positive predictive value was 0.4 and the negative predictive value was 1.0. The MST is easy to use and is a strong predictor of nutritional status. The malnutrition screening tool is a simple, quick, valid tool that can be used to identify radiation oncology outpatients who are at risk of malnutrition.

Osteolymphoma (primary bone lymphoma): an Australian review of 70 cases. Australasian Radiation Oncology Lymphoma Group (AROLG)

BACKGROUND

To examine prognostic factors, treatment outcomes and design future studies for Osteolymphoma (OL)--also known as primary bone lymphoma.

METHODS

Between 1979 and 1993, 70 patients with OL were treated in nine Australian centres. The effect of patient-, tumour-, and treatment-related factors on local control, distant disease-free survival and overall survival were assessed by multivariate analysis.

RESULTS

Most patients (94%) received radiotherapy (RT) (median dose 40 Gy) and 56% received chemotherapy. Multifocal disease was present in 20% of patients. The five year rates of overall survival and local control were 59% and 82%. Although there was a trend towards better results with the addition of chemotherapy, on multivariate analysis, there were no factors identified which appeared to impact upon overall and disease-free survival. Among the distant recurrences, there was a high proportion in bone (33%). Six patients suffered pathological fractures after treatment.

CONCLUSION

High rates of local control were achieved by RT, but the overall survival remains relatively poor, worse than nodal lymphoma. The natural history of the disease suggests that OL may be a distinct entity, different to nodal lymphomas, so the results of clinical trials in nodal lymphoma may not be relevant to OL. Prospective studies could define the outcome of combined modality therapy and set a benchmark for testing further proposals, as well as improving our knowledge of the clinical features of OL.

The doses received by the breast during mantle radiotherapy

PURPOSE

To accurately measure the dose received by the breast during mantle radiotherapy.

METHODS AND MATERIALS

A phantom containing lung-equivalent material was used to measure the doses received by the breast during mantle radiotherapy given by anterior and posterior opposing fields. These were measured using thermoluminescent dosimeters and compared with point dose calculations obtained by computer planning.

RESULTS

Most of the breast lies under the lung shields or inferior to the mantle field, but the upper outer quadrant of the breast remains unshielded. In the unshielded areas of the breast, the average dose measured was nearly 13% higher than the dose prescribed at the central axis. In the shielded parts of the breast, the average measured dose was nearly 10% of the dose prescribed at the central axes, decreasing from 18% superiorly to 4% inferiorly. The posterior field contributed 45% to the dose in the breast, even though doses were prescribed at the midplane. The computer calculations systematically varied from measured doses by up to 35%, becoming less accurate towards the inferior edge of the field.

CONCLUSIONS

In a conventional course of mantle radiotherapy (for example, 36 Gy in 20 fractions), most of the breast is shielded but will receive a dose of 3-4 Gy, higher than expected largely due to internally scattered radiation passing through the lungs from the posterior field. Computer dose calculations may poorly reflect actual off-axis doses in large fields with complex shielding, containing inhomogeneous tissue.

The role of the gallium scan in primary extranodal lymphoma

The purpose of this study was to examine the factors influencing gallium scan positivity for patients with primary extranodal lymphoma and to examine the role of the gallium scan in staging the disease and assessing response to initial treatment.

METHODS

Ninety-two patients with extranodal lymphoma who had a gallium scan were reviewed. The influences of tumor site, size, grade and the presence of clinically detectable disease after biopsy on the rate of gallium scan positivity were analyzed. The role of the gallium scan in staging and selecting treatment was assessed. Nineteen patients had a gallium scan to assess their response to treatment, and its predictive value was reviewed.

RESULTS

The overall gallium scan positivity (sensitivity) rate was 70%. This rate was low in patients whose extranodal lymphoma occurred in skin, intestine and testis, or was low grade (0%-25%). When these patients were excluded, the rate rose to 88%. Gallium scan positivity was not related to the presence of clinically detectable disease after biopsy and there was insufficient data about tumor size to determine a relationship. The gallium scan increased the disease stage in six patients (7%) and changed the initial treatment in six patients (7%). The gallium scan became negative in 15 (79%) of those patients who had a gallium scan to assess their response to treatment. All but two of these patients remain alive with a median follow-up of 3.75 yr.

CONCLUSION

The gallium scan was rarely positive for patients with skin, intestinal, testicular and low-grade lymphomas, but was otherwise comparable to lymphoma arising in lymph nodes. The result affected staging or treatment in seven patients (8%). After treatment, an initially-positive gallium scan usually became negative, a conversion associated with a favorable outcome.

Association of hereditary angioedema and hereditary breast cancer

A family is presented in whom hereditary angioedema (HAE) and hereditary breast cancer were coexistent, an association not previously reported. A potential for genetic and treatment-related interactions between the two conditions exists. The use of the hormonal agent danazol to suppress HAE is unlikely to adversely affect the development or outcome of breast cancer. Surgery, chemotherapy, and radiotherapy were received by affected family members, without triggering edema. Whether hormonal breast cancer treatment affects the suppression of HAE by danazol remains unknown.

Diagnostic difficulties in extraosseous Ewing's sarcoma: a proposal for diagnostic criteria

Five cases diagnosed as extraosseous Ewing's sarcoma (EES) during a 15-year period, and the relevant literature, were reviewed. The diagnosis in these cases was difficult to confirm, mainly because the distinction between the osseous form of Ewing's sarcoma (OES) and either periosteal reactions or direct tumour invasion into adjacent bone by EES was often unclear. The literature suggests that other authors have also encountered difficulties. The authors believe that many cases reported as EES are likely to have been OES. This distinction has some importance, as the two conditions are usually treated in differing ways. The following criteria are proposed for the diagnosis of primary EES: (i) no evidence of bony involvement on magnetic resonance imaging; (ii) no evidence of increased uptake in bone or periosteum adjacent to the tumour on static isotope bone scan images; (iii) a small round cell tumour with no differentiating features on light microscopy, immunochemistry or electron microscopy; and (iv) demonstration of cytoplasmic glycogen.

Primary bone lymphoma (osteolymphoma)

Seventeen patients with primary lymphoma of bone are reviewed. In 15 patients treated with radical radiotherapy, local progression or recurrence occurred in four. The results support the use of radiotherapy alone, using doses of 45-50 Gy. Although small numbers prevent firm conclusions, the inclusion of the whole bone or regional nodes in the irradiated volume did not appear to improve results. Eight patients received systemic chemotherapy with no apparent improvement in rates of relapse. Two patients suffered pathological fractures after radiotherapy in the absence of recurrence at the fracture site; however, osteomyelitis, older age, Paget's disease, high-dose prednisolone and whole-bone radiotherapy may have added to the risk of fracture. Because of the many complex names and selection criteria applied to this condition, literature searching and comparison between studies was difficult. The simple term osteolymphoma is proposed, consistent with other primary bone conditions.

Radiotherapy for melanotic freckles

Five patients who received radiotherapy (RT) for 7 melanotic freckles (MF, also known as Hutchinson's freckles, lentigo maligna) were reviewed 8 to 37 months after their treatment by RT. Local control and a favourable cosmetic result occurred in all patients. Treatment toxicity was minimal. Few reports about the use of RT for MF exist. Many other treatments including observation alone have been associated with high rates of recurrence, and in some cases conversion to invasive melanoma has occurred. RT appears to be a safe and effective treatment for this condition, providing that doses equivalent to 44 Gy in 11 fractions or more are given.

Orchidectomy prior to definitive radiotherapy for localized prostatic cancer

PURPOSE

To identify potential survival benefits of cytoreductive orchidectomy performed prior to definitive radiation for localized prostate cancer.

METHODS AND MATERIALS

Between 1977-1988, all patients with localized prostatic cancer from the Wellington Region received definitive radiotherapy (n = 200). One referring urologist Peter M. Meffen (P.M.M.) had commenced a program of prior orchidectomy followed by definitive radiation treatment (median time to radiation therapy was 5 months, n = 30).

RESULTS

Five-year overall survival (OS) and relapse-free survival (RFS) for each stage were Stage A 82%, and 82%; Stage B 75%, and 61%; Stage C 57%, and 38%, respectively. Ten-year OS and RFS for each stage were Stage A 78%, and 72%; Stage B 51%, and 18%; Stage C 32% and 0%, respectively. Multivariate analysis identified prior orchidectomy treatment and histological grade as independently significant prognostic factors for OS and RFS. Factors influencing RFS were clinical stage, prior orchidectomy, and histological grade. Prior orchidectomy was associated with an increase in OS at 5 years when compared to those patients receiving radiotherapy alone, 86% vs. 69%, and maintained at 10 years, 82% vs. 46% (p < 0.05). The two groups were comparable by stage, histological grade, and age. There were no changes in the referral pattern during the study period.

CONCLUSIONS

Our results suggest that prior cytoreduction by orchidectomy has a beneficial effect on OS and RFS for patients with localized prostate cancer. It is unclear whether survival benefits are due to the cytoreductive therapy, the adjuvant therapy, or a combination of both. Further study in this area is warranted, ideally in the form of randomized prospective clinical trials.

Concurrent 5-fluorouracil, mitomycin C and irradiation in locally advanced cervix cancer

We reviewed 177 patients treated with radical radiotherapy for locally advanced (FIGO stages IIB, IIIA, IIIB) cervix cancer between January 1979 and December 1989. The radiotherapy was given by external beam treatment to the pelvis and by an intracavitary caesium insertion. Ninety-three patients also received chemotherapy which consisted of infusional 5-fluorouracil during the first and last weeks of the external beam component of the radiotherapy, combined with bolus mitomycin C (group A, 64 patients) or without mitomycin C (group B, 29 patients). These groups were compared with patients treated by radiotherapy alone (group C, 84 patients). The median follow-up was 7.2 years. The median survival time for all patients was 47 months, but was significantly higher (87 months, p = 0.004) for group A. Rates of relapse-free survival and local control were also higher in group A. Toxicity was assessed in detail using the Franco-Italian glossary. There was a relatively high rate of complications, particularly in group A, with 36% of patients having grade 3 or 4 complications. This increase in toxicity persisted through all follow-up time intervals. Patients in group B also demonstrated a higher rate of toxicity than group C, but this increase was limited to the first 6 months of follow-up. The use of mitomycin C in addition to radiotherapy and 5-fluorouracil should be regarded with caution, as other studies have also shown that toxicity is increased, but without improvements in survival.

Heterotopic bone formation affecting the hip joint is preventable in high risk patients by post-operative radiation

Between 1984 and 1993, 40 high risk patients (45 hips) received postoperative irradiation as prophylaxis against heterotopic ossification (HO). Radiotherapy was commenced within 5 days of the surgery in 43 of 45 hips. The development of HO was assessed by comparison of radiographic films prior to irradiation and at least 2 months after treatment (median interval 12 months). Progression of HO was observed in only two of 45 hips (4.3%) and of clinical significance in one (2.2%). Treatment was well tolerated with no acute complications or loosening of prosthetic components attributable to irradiation. During the study period, the treatment programme changed from 20 Gy in 10 fractions to 6-8 Gy in a single fraction, without loss of treatment efficacy. As well as improving resource utilization, single fraction techniques allow fewer patient transfers thereby reducing patient discomfort and risk of hip dislocation. This procedure is uncomplicated and should be considered more widely in the management of this disabling non-malignant condition.

The ulnar artery free flap: the first 7 years

This paper reviews 7 years of experience with the ulnar artery free flap at the Wellington Regional Plastic Surgery Unit. It has become the free flap we use most commonly to repair defects after resection of intraoral cancers, other head and neck defects, and soft-tissue defects of the lower limbs. Of 56 attempted cases, 52 have been successful. Two procedures were abandoned intraoperatively because of abnormalities in vascular pattern, and 2 failed in the lower limb because of anastomotic failure. These 4 cases occurred early in the development of the technique; all cases in the last 4 years have been successful. The ulnar artery free flap has some important advantages over the radial artery free flap, including ease of donor site repair, cosmetic acceptability, and hairlessness.

Cervical cancer: changing trends in the Wellington region

AIM

To identify changes in patient and tumour characteristics of women with carcinoma of the cervix treated through the Wellington Regional oncology unit between 1975-89.

METHODS

The medical records of the patients treated between 1985-9 were reviewed. The age and stage of disease was noted in each case and results compared with the previous two 5-year cohorts.

RESULTS

Over the 15 year period there was no obvious reduction in the incidence of cervical cancer. There was a significant trend towards women presenting with earlier stage disease. In the 1985-9 cohort, patients less than 40 years old were significantly more likely to present with earlier stage disease, and there was no detectable difference between the incidence of cervical cancer in Maori and nonMaori.

CONCLUSIONS

The results indicate that cervical screening has not yet made an impact on the incidence of cervical cancer in the greater Wellington region, and possible reasons for this are discussed.

Artificial pneumothorax can be used to prevent lung toxicity in chest wall radiotherapy

We report two patients in whom an artificial pneumothorax was induced to reduce the risk of radiation pneumonitis and fibrosis after treatment for chest wall tumours. The procedure was well tolerated; the only complication observed was a single episode of syncope following over-inflation. High doses of radiation were given to large chest wall fields with no clinical or radiological evidence of pneumonitis or fibrosis, either during or after treatment. The available literature on the use of artificial pneumothorax with radiation is reviewed, and the technique of induction is described.

Prostate irradiation does not affect the serum prostatic acid phosphatase level

Twenty-nine consecutive patients with localized prostatic carcinoma were studied prospectively to assess the effect of radical pelvic irradiation on the serum prostatic acid phosphatase level (SPAPL). The doses of radiation given ranged from 64.00 to 66.00 Gy. SPAPLs were taken before, during and shortly after their treatment. No significant individual variations in SPAPLs were found. When patients with prostatic carcinoma show rises in serum prostatic acid phosphatase during or after pelvic irradiation, these are unlikely to be due to their treatment and occult pelvic nodal or bony disease should be considered.