Radiation therapy for early stage Hodgkin's disease: Australasian patterns of care. Australasian Radiation Oncology Lymphoma Group

Should cancer survivors fear radiation-induced sarcomas?

Purpose/Results. Ionizing radiation is carcinogenic and the induction of a second malignancy is a serious potential long-term complication of radiotherapy. The incidence of radiation-induced sarcomas was evaluated from many large epidemiological surveys of long-term cancer survivors reported in the literature over the past 30 years and only one case was found for every 1000 patients irradiated.

Discussion. Although greater numbers of cancer patients are receiving radical radiotherapy and surviving free of disease for longer intervals, cases of radiation-induced sarcomas are rare and should not deter patients from accepting radiotherapy as treatment for curable cancers. With improvements in the administration of radiotherapy over the past two decades which are resulting in less damage to bone and soft tissues, it is likely that fewer cases of this condition will be seen in the future. If these sarcomas are diagnosed early, long-term survival can be achieved with surgical excision and possibly re-irradiation, as occurs in other types of sarcomas.

Long-term outcome after radiotherapy alone for lymphocyte-predominant Hodgkin lymphoma

BACKGROUND

The curative potential of radiotherapy (RT) alone as initial treatment for patients with Stage I-II lymphocyte-predominant Hodgkin lymphoma (LPHL) has not been defined well.

METHODS

Two hundred two patients who were treated between 1969 and 1995 were evaluated in a retrospective, multicenter study.

RESULTS

Patient characteristics were as follows: The median age was 31 years, 75% of patients were male, 80% of patients had Ann Arbor Stage I disease, 1% of patients had bulky disease, 3% of patients had B symptoms, 1% of patients had extranodal involvement, and 80% of patients had supradiaphragmatic disease. The RT fields were a full mantle field in 52% of patients, less than a full mantle field in 24% of patients, an inverted-Y field in 17% of patients, less than an inverted-Y field in 3% of patients, and total lymph node irradiation in 3% of patients. The median dose was 36 Gray. The median follow-up was 15 years. The overall survival (OS) rate at 15 years was 83%, and freedom from progression (FFP) was observed in 82% of patients, including 84% of patients with Stage I disease and 73% of patients with Stage II disease. No recurrent LPHL and only 1 patient with non-Hodgkin lymphoma (NHL) were reported after 15 years. Adverse prognostic factors that were identified on multifactor analysis were as follows: for OS, age 45 years or older (P < 0.0005), the presence of B symptoms (P = 0.002), increasing number of sites (P = 0.015); for FFP, increasing number of sites (P = 0.002). No significant difference was found in FFP in a comparison of patients who received elective mediastinal RT with patients who did not receive mediastinal RT (P = 0.11). Causes of death at 15 years were LPHL in 3% of patients, NHL in 2% of patients, in-field malignancy in 2% of patients, in-field cardiac/respiratory in 4% of patients, and other in 6% of patients.

CONCLUSIONS

The current data suggested that RT potentially may be curative for patients with Stage I-II LPHL and raise the possibility that limited-field RT may be used without loss of treatment efficacy. Involved-field RT warrants further investigation for patients with early-stage LPHL.

Risk-adapted therapy for clinical stage I-II Hodgkin's disease: 7-years results of radiotherapy alone for low-risk disease, and ABVD and radiotherapy for high-risk disease

Treatment outcomes were documented for 204 adult patients with clinical Stage I-II Hodgkin's disease who were treated with risk-adapted ABVD (doxorubicin, bleomycin, vinblastine and dacarbazine) and radiotherapy (RT) at the Toronto-Sunnybrook Regional Cancer Centre between 1984 and 1994. Forty-nine patients with clinical Stage I disease (excluding bulky mediastinal presentations) and 50 patients with a combination of clinical Stage IIA disease, age 50 years or less, and favourable pathology (lymphocyte predominant or nodular sclerosing histology) were identified as low risk and treated with RT alone to 35 Gy. One hundred and five high-risk patients were treated with chemotherapy (86 with ABVD) followed by RT to 25 Gy. The 7-year cause-specific, overall and disease-free survivals were 95%, 90% and 75% respectively for the low-risk cohort, and 91%, 90% and 88% respectively for the high-risk cohort. In-field relapses accounted for 50% of the failures in both groups. Sixteen of 24 (67%) patients with RT failure and 6/14 (43%) with combined modality therapy (CMT) failure were salvaged. Twenty-eight per cent of the patients treated with RT and 21% of those treated with CMT developed hypothyroidism by 7 years. Fatal complications were recorded in 6% of the low-risk patients managed with RT and 8% of high-risk patients managed with CMT. Septic death and second malignancy accounted for the majority of treatment-related fatalities. Risk-adapted therapy emphasizing RT alone for selected patients with favourable prognostic factors and CMT based on ABVD provides excellent long-term disease control. Further treatment refinements, including the wider application of CMT with lower doses of chemotherapy and RT, will be required to reduce the rate of fatal complications to more acceptable levels.

Mantle planning: report of the Australasian Radiation Oncology Lymphoma Group film survey and consensus guidelines

The purpose of the present paper was to measure the variation in mantle planning in Australia and New Zealand. A chest X-ray (CXR) of a patient in the supine position with a neck node marked by wire was sent to every radiation oncologist in Australia and New Zealand. They were to mark on the CXR the lung blocks that they would use to treat this patient, assuming that the patient had stage IA Hodgkin's disease. These marks were compared with a small sample of radiologists who were asked to define the mediastinum on the same CXR. Radiation oncologists were also asked to complete a short questionnaire about other modifications to their treatment fields and their experience with this technique. One hundred and six films were sent out and 44 radiation oncologists replied. There was a maximum variation in the placement of their lung blocks of 6 cm. Half of the lung blocks were within a 2-cm range. One respondent said they would not use a mantle field to treat this patient. Mediastinal coverage was inadequate in at least 50% of cases. There was a very large variation in mantle field planning practices within Australia and New Zealand. For this reason Australasian Radiation Oncology Lymphoma Group has produced consensus guidelines for mantle block design. These are appended to the present paper.

Increased survival in patients diagnosed with Hodgkin's disease in Tasmania, 1972-1992

BACKGROUND

It has been shown that in certain populations the prognosis of Hodgkin's disease (HD) has improved markedly since the late 1960s. This has not been formally demonstrated in an Australian population.

AIMS

To review all patients in Tasmania diagnosed with HD between 1972 and 1992, and to ascertain whether variation in survival is evident in this group over this period.

METHODS

Tasmanian patients with HD diagnosed from 1978 to 1992 were identified retrospectively from the Tasmanian Cancer Registry database. Identification of those diagnosed prior to 1978 was obtained from a previously published data set. To be valid for inclusion, subjects were required to have been diagnosed between January 1972 and December 1992, enabling a minimum four year follow up period. Survival was assessed by contacting patients' medical practitioners and by examining the most current electoral roll, medical records, and the register of births, deaths and marriages. Univariate and multivariate analyses were performed of the influence on prognosis of age, sex, histological subtype and epoch of diagnosis; information concerning stage of disease was not available.

RESULTS

During the period of this study 206 patients were newly diagnosed as having HD. Comparisons of cases diagnosed in the successive seven-year epochs 1972-8, 1979-85 and 1986-92 revealed a significant increase in survival duration (p = 0.023), with ten year survival rates of 46%, 55% and 73% respectively. In a multivariate analysis adjusting for age, sex and histology, each successive epoch was associated with an estimated 28% reduction in the death rate relative to the preceding epoch (p = 0.022).

CONCLUSIONS

There was a significant improvement in the survival duration of patients diagnosed with HD in Tasmania over the period 1972-92, which was possibly due to a combination of better diagnostic techniques and more effective treatments.

[Late effects of ionizing radiations on the thyroid gland]

The thyroid is the purest endocrine gland in the body and is likely to produce clinically significant abnormalities after external radiotherapy. Functional clinical modifications after direct irradiation exceeding 30 Gy are essentially related to hypothyroidism which may be clinically overt or subclinical with normal serum free thyroxine levels and high thyrotropin concentrations; the risk of hyperthyroidism, silent thyroiditis and Hashimoto's disease is also increased. Secondary hypothyroidism related to irradiation of the hypothalamus and the pituitary gland may arise with doses over 40-50 Gy following treatment for brain and nasopharyngeal tumors--Morphological glandular modifications induced by radiotherapy are responsible for the appearance of benign adenomas, more rarely cystic degenerations and specially well differentiated papillary or follicular carcinomas among children and adults. After irradiation during childhood for benign or malignant tumors, thyroid cancers are more frequent, higher for younger children, and the relative excess risk is increased from 15.6-to 53-fold; tumors can belatedly occur, more than 35 years after initial therapy. Thereby, in order to limit excess morbidity, it is evident that long term supervision with careful clinical and biological evaluations is necessary for patients who previously received neck, upper mediastinum and pituitary radiation therapy.

Multicentre dosimetry study of mantle treatment in Australia and New Zealand

PURPOSE

To determine the difference between expected and measured dose for patients prescribed a mantle treatment for Hodgkin's disease and estimate the range of dose at critical sites and between different treatment centres.

METHODS AND MATERIALS

Twenty three radiotherapy centres were surveyed with regard to the accuracy of dose delivery to a custom-built upper-torso phantom. Thermoluminescent dosimeters were used to monitor the delivered dose at sites such as mid-plane, spinal cord, neck, axilla and lung.

RESULTS

The intended dose to the phantom at each centre was 1 Gy to central axis mid-plane. Of the centres surveyed, the median measured dose to this region was 0.96 Gy with a minimum of 0.92 and a maximum of 1.00 Gy. Median dose to the axilla region was low (0.90 Gy) whereas median dose to the blocked lung and neck region were higher than expected, 0.18 Gy and 1.25 Gy, respectively. The 95% confidence interval on the reported relative dose using the 4000 thermoluminescence dosimetry readings in this study was +/- 1.5%

CONCLUSION

In this controlled experiment, using conventional methods to calculate dose, there was a surprising variability in the dose delivered at the central axis mid-plane position. This was traced to lack of uniformity in the use of equivalent squares to calculate the output factor. The measured doses to axilla and lung are explained by photon and electron scattering effects. Centres, where dose compensation was included, had a superior dose homogeneity in the neck. The off-axis dose calculations depend on computer planning software but the magnitude of these differences is secondary to that of central axis mid-point dose differences. Improved consistency of dose calculation techniques between centres would enable more reliable dose response evaluation from multicentre clinical studies of Hodgkin's disease.

Radiotherapy for early infradiaphragmatic Hodgkin's disease: the Australasian experience

PURPOSE

To review the Australasian results of Stage I and IIA Infradiaphragmatic Hodgkin's Disease (IHD) treated solely by irradiation.

METHODS AND MATERIALS

Eligible patients had IHD only and were treated by irradiation with curative intent over the period of 1969 to 1988. Ten radiation oncology centres from within Australia and New Zealand were surveyed for patient, tumour and treatment variables. Disease free rates, survival and complications were analysed.

RESULTS

106 patients with IHD were studied. The average potential follow up was 9.4 years. The male to female ratio was 3.3:1. The median age was 37.5 years. Histological subgroups were as follows; lymphocyte predominant 43%, mixed cellularity 21%, lymphocyte depleted 5%, nodular sclerosing 27% and unclassifiable 4%. Fifty nine patients had laparotomy of which 22 (37%) were positive for tumour. Nine laparotomies were performed for diagnosis and the remainder for staging. One patient was up-staged by laparotomy and three were down-staged. Sixty-eight patients presented with inguinal disease alone, five with abdominal disease alone, 19 with two sites of involvement and 12 with inguinal, pelvic and abdominal disease. In two patients the site was unknown. There was no correlation between site of involvement, age, sex or histological subtype. Forty seven cases were clinically staged (CS) as follows: CS IA-23, CS IIA-24. The other 59 were pathologically staged (PS) as follows: PS IA-37, PS IB-1, PS IIA-21. Treatment consisted of involved field alone (16), inverted Y (68), inverted Y and spleen (13), para-aortic irradiation only (3), or total nodal irradiation (6). Mean dose was 37 Gy. There were 30 recurrences to give an acturial 10-year disease-free rate of 70%. In multivariate analysis lower number of tumour sites, lymphocyte predominant histology and higher dose were all significantly correlated with higher disease free rates. Eight patients died of Hodgkin's disease and 19 of other causes. The 10-year overall survival rate was 71%. Older age and higher number of disease sites were significantly correlated with shorter survival. Fourteen of 30 relapses may have been avoidable by the use of total nodal irradiation. In particular ten of 21 patients with abdominal disease relapsed in nodal sites which would have been covered by total nodal irradiation.

CONCLUSIONS

The rate of control in IHD could perhaps be improved by avoiding involved field irradiation or by aggressive therapy with total nodal irradiation or combined modality chemo-irradiation in Stage II disease. Staging laparotomy does not appear to be indicated.

Breast cancer following treatment for Hodgkin's disease: the need for screening in a young population. Australasian Radiation Oncology Lymphoma Group (AROLG)

Several recent publications have highlighted the issue of an increased risk of breast cancer in women treated with radiotherapy, chemotherapy, or combined modality therapy for Hodgkin's disease. The risk is greatest in women 30 years or younger at the time of treatment. In the Australasian Radiation Oncology Lymphoma Group database, 60% of women fell into this age category. This article reviews the available data pertaining to induction of breast cancer by radiotherapy for Hodgkin's disease. Breast examination should now be an integral part of the long term follow up for these women. There is also a case for the use of screening mammography. Any breast mass developing subsequent to treatment for Hodgkin's disease should be regarded with a high index of clinical suspicion and, accordingly, biopsies should be performed in the majority of cases, even when mammography is negative.