Hyperbaric Oxygen Therapy - Hyperbaric Chamber Information ...

The different studies also applied varying doses of radiation to the affected region,
ranging from 3,600 to 6,000 rads. Moreover, treatments were spread over differing
numbers of days and used dissimilar fractions. In the study by Plenk, 117 patients were
exposed to two different radiation doses and dosing schedules based on their exposure to
HBO or air.
Assessment of heterogeneity
Due to the inadequacy with which study populations, methodologies, and intervention
and comparison protocols were described, this review does not attempt to arrive at a
common effect estimate through statistical methods. The results of each study are
described below.
Review of published clinical experience
The study by Cade et al114 examined actuarial survival rates (Table 75) and found no
statistically significant differences between the survival curves (unstated statistic, p =
0.72). Stratification by histological type of tumour failed to uncover differences in
survival (transitional tumours, p = 0.61; anaplastic tumours, p = 0.62; other types, p =
0.32).
Table 75 Percentage of population surviving by year since trial entry following treatment for bladder
cancer in intervention and comparison groups. 114-117 *
First Author and
Year of Publication
Group
Assignment
Sample
Size
Percentage Survival by Year Since Trial Entry
1 2 3 4 5
p †
Cade 1978 114
Kirk 1976 115
Dische 1973 116
Plenk 1972 117
Intervention 118 64 42 36 31 28
Comparison 118 64 47 37 35 30
Intervention 14 43
No Data
Comparison 13
31
Intervention 28 54 37 27 28 20
Comparison 39 64 39 37 39 25
Intervention 19 53 37 43 22
Comparison 21 42 19 8 11
* Abbreviation: NS = not statistically significant.
74 Hyperbaric oxygen therapy
No
Data
† The statistic used to compare survival experiences is not given. These values are as they appear in the publications.
‡ Independent calculation based on exact binomial methods.
Kirk et al 115 provide survival proportions only at the fifth year post therapy (Table 75).
Exact binomial methods failed to provide evidence of a statistically significant difference
between the two groups (p = 0.52). The study was halted due to high-dose effects that
included post-radiation haematuria of sufficient severity to warrant cystectomies (n = 8)
or ureteral transplants (n = 1). Dische 116 failed to find statistically significant differences
in the survival experiences of the two groups, even after extensive post-hoc stratification
according to treatment received or tumour size.
Plenk 117 reported statistically significant survival benefits in those subjects receiving
HBO. Median survival times for the intervention and comparison groups were 25.9 and
13.6 months respectively.
0.72
0.52 ‡
NS