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response has been given. Although data is inconclusive, there is some evidence of a dose-response effect, either for > 45 Gy versus < 45 Gy or > 50 Gy versus < 50 Gy.

heterogeneous mix of tumour parameters and prognostic factors, including extent of resection and grade.

DOSE-RESPONSE RELATIONSHIP When interpreting retrospective data it is difficult to rule out selection for lower RT dose based on adverse prognostic features e.g. age and tumour size, with lower dose RT being employed for younger patients and those with larger target volumes. It is also difficult in some studies to analyse the impact of dose on response when a dose-fractionation regimen has been uniformly applied, or when there is a high local relapse rate. This review includes 11 series of patients reported since the early 1990s [4–14] and comprises 526 patients, involving treatment over time periods between 14 and 38 years. In these series the mean number of patients treated per institution per year was 1.8. This reflects the low incidence of EP. Overall 5-year survival varied from 40 to 79%. Seven of the 11 series demonstrated that the outcome was related to grade [4,7,9,11–14] and 7 series demonstrated the outcome related to the extent of surgical resection [4–7,9,13,14]. For incompletely resected tumours 5-year OS varied from 22 to 64.1%, whereas for completely resected tumours this was from 61 to 80%. DOSE-RESPONSE DATA Table I shows outcome data from 11 series reported since the early 1990s, in which information on dose-

ROLE OF HYPERFRACTIONATED RADIOTHERAPY (HFRT)

There is no data on the radiobiology of EP. Thus consideration of the potential benefit for HFRT relies on the empirical analysis of series of patients treated by HFRT. In the PediatricOncologyGroup (POG) 9132 study, in 15 patients who had incomplete resection a HFRT dose of 69.6 Gy given in 58 twice daily fractions resulted in a 3-year EFS of 52% [15]. This compared favourably with a similar group treated in an earlier study with conventional fractionation, who had a 5-year EFS of 27%. Several other studies have explored the role of HFRT in ependymoma and results are awaited. ROLE OF DURATION OF RT In one study [16] the impact on outcome of prolonga- tion of the duration of RT has been examined. In this study in patients for whom the RT treatment duration was < 50 days, the 5-year OS was 85.5% compared with 45.5% for 50 days or greater ( P ¼ 0.01). The 5-year local control rate for patients whose treatment duration was < 50 days was 70.6% compared with 45.5% for 50 days or greater ( P ¼ 0.05). In this type of analysis it is important to rule out an impact of other prognostic factors. However, this study is of interest and for future analyses of outcome of RT for

TABLE I. Influence of Radiotherapy (RT) Dose on Outcome

RT dose

No. of patients

< 45 Gy

< 50 Gy

Author [reference]

Institution

Dates

45 Gy

50 Gy

Goldwein et al., 1990 [6]

Philadelphia

1970–1988

51

18% 5Y OS 51% 5Y OS 0% 5Y PFS 32% 5Y PFS

Vanuytsel et al., 1992 [7]

Royal Marsden 1952–1988

93

53% 5Y OS

55% 5Y OS ( > 50 Gy)

( < ¼ 50 Gy)

Chiu et al., 1992 [8]

MD Anderson 1955–1986

25 65 37

33% 5Y OS 58% 5Y OS 51% 5Y OS 69% 5Y OS

Rousseau et al., 1994 [4] Carrie et al., 1995 [9]

IGR, Paris

1975–1989 1974–1993

Lyon

6/12 (50%) relapsed ( < 50 Gy)

6/16 (37.5%) relapsed ( > 50 Gy)

Pollack et al., 1995 [5]

Pittsburgh

1975–1993

37

Routinely applied to a dose > ¼ 50 Gy)

Stuben et al., 1997 [10]

Essen

1963–1995

41

36% 5Y PFS ( 45 Gy)

45% 5Y PFS ( > 45 Gy)

Schild et al., 1998 [11]

Mayo clinic

1963–1994 1966–1989 1965–1997

45 32 52

‘No dose response’ N/A (high loc rec rate)

Mc Laughlin et al., 1998 [12] Gainesville

GTR þ > 45 Gy LC 76.9%

Paulino et al., 2002 [13]

Iowa

Oya et al., 2002 [14]

Kyoto

1961–1999

48

Uniformly applied, modified according to tumour size, no association ( < 55 Gy vs. > ¼ 55 Gy)

PFS, progression-free survival; OS, overall survival; GTR, gross total resection; LC, local control.