Medulloblastoma in children. Current prognostic factors

The radiation treatment of medulloblastoma

“…In Toronto a positive post-operative CT (N = 15) was associated with a 42% five year disease free survival, compared with 82% (N = 13) in the absence of such lesions, and if the first CT following radiation treatment was negative the five year disease free survival was 79% (N = 38) compared with 44% (N = 9) when positive [10]. Similar results have been reported from Seattle.…”

“…In general, children less than two years old do rather less well than older children, as a consequence of an increased number of poor prognostic factors at this age, but for equal stage there is no significant difference in outcome [10]. There remains no hard evidence that the radio curability of meduUoblastoma is age dependent.…”

“…The cribriform region cannot be boosted without some increase in dose to the eyes and the disadvantage of this, in particular the potential for cataract formation, has to be balanced against the prevention of this pattern of relapse. It is a difficult decision, but isolated subfrontal relapse is uncommon, none of 72 children treated in Toronto 1977-87, for example [10], although we have seen this problem twice subsequently. The author elects to be conservative and not to boost this region.…”

“…Overall five year survival rates in excess of 50% were obtained with this approach as illustrated by the Toronto experience, indeed with current radiation treatment methods rates in excess of 60% may be expected [10,19]. Whether the interval from resection to the start of radiation treatment is a prognostic factor is unclear.…”

“…In Toronto from 1958-78, 79 patients started post operative radiation treatment within 10 days of resection and in 40 patients there was delay, but without any significant difference in outcome [19]. From 1977-87 for subtotally resected patients who commenced treatment within fourteen days (N = 20) the five year disease free survival was 61% compared to 30% for those with a greater delay (N = 23), a result approaching significance [10]. Most investigators consider it prudent to minimize this delay in patients to be treated by irradiation alone.…”