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.