ALLC 1992 - childhood acute lymphoblastic leukaemia - data structure and protocols

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ALLC 1992 data preparation: brief written protocol

Strict confidentiality of trial results is observed. Information is held in the Clinical Trial Service Unit computers in a form which can be accessed only by known individuals.

All patient records are converted into 'pink form' (1992) format (described below) if not already supplied in it. Results received as tables are converted into sets of synthetic 'pink form' records. The following routine checks (where appropriate) are performed on every 'pink form' compilation:

The total numbers of patients and the distributions of randomisation age, gender, initial leukocyte count (w.b.c.) and first event types are checked for any significant imbalance between treatment groups. These four distributions are compared as follows. Patients are grouped into five categories according to randomisation age (0 - 2 years; 3 - 14 years; 15 - 19 years; 20 - 99 years; unknown) and a chi-squared test is applied to the population of the four categories found in each treatment group. Similarly, three categories are formed for gender (male; female; unknown), five for w.b.c. (0·0 - 0·9; 1·0 - 9·9; 10·0 - 99·9; 100·0 + x 109 per litre; unknown) and seven for first event types (death in remission; haematological relapse; central nervous system relapse; testicular relapse; other relapse, multiple relapse; unknown) and these are tested in the same way as the categories formed for randomisation ages.

If an event such as relapse is reported at a date later than the quoted last follow-up date, the last follow-up date is automatically changed to the later date. The completeness of follow-up is then calculated for the end of each calendar year. The distributions of randomisation dates, randomisation ages, time elapsed since last follow-up and log w.b.c. are checked for any significant imbalance between treatment groups in two ways as follows. Firstly, a t-test is applied to the difference between the mean value of each distribution for patients in each group with the corresponding mean for patients in the remainder. Secondly, an F-ratio is calculated for each distribution by comparing the variance between the groups with the variance within the groups. The distribution of time elapsed since last follow-up is also checked in these two ways for any significant imbalance between those patients with and those patients without a subsequent recorded event. Finally, the distribution of time elapsed since randomisation is checked in the same two ways for any significant imbalance between patients in the two categories of known gender, the four categories of age and the four categories of known w.b.c.

Where patient serial numbers form an obvious sequence it is checked for missing numbers.

A tabulated breakdown of variables is produced for each trial, together (where relevant) with lists of patients in 'problematical' categories such as those with lapsed follow-up, uncertain death cause or second malignancy site. Graphs of accrual date and the proportion of living patients still on follow-up as a function of time from randomisation by treatment allocation are also produced, together with Kaplan-Meier life-table curves. Before trial data are finally incorporated into the overview, the analyses described above are sent to the participating trialist(s) for checking and approval.


Please address inquiries concerning data preparation and checking to:

Specification of ALLC 1992 'pink form' format

Item Description FORTRAN Columns Details Abbreviation
0 Trial/stratum identifying code I6 1 - 6 Trial
1 Patient identifier (or sequence number) A12 8 - 19 Patient
2 Gender I1 21
Value Description Abbreviation
Date of birth  I6  23 - 28  DDMMYY  Birth Date 
Initial w.b.c.  I5  30 - 34 
Value Description Abbreviation
x 108 / litre 
-1  Unknown 
Init. w.b.c. 
5 Diagnosis date  I6  36 - 41  DDMMYY  1-Trt. Date 
Date of first remission  I6  43 - 48 
Value Description Abbreviation
-1  Definitely no CR 
-2  CR on unknown date 
1st CR Date 
Randomisation date  I6  50 - 55  DDMMYY  Randn. Date
8 Treatment group allocated (as on master list) I1 57 Trt. Grp
9 Type of first event  A3  59 - 61 
Value Description Abbreviation
Death in remission 
Haematological relapse 
C.N.S. relapse 
Testicular relapse 
Other relapse 
1st Event 
10  Date of first event I6  63 - 68  DDMMYY  Event Date 
11  State when last traced  I1  70 
Value Description Abbreviation
Alive  Alive 
Dead  Dead 
Lost  Lost 
12  Date died or last traced  I6  72 - 77  DDMMYY  L.F.U. 
13  Cause of death (extra category)  I2  78 - 79 
Value Description Abbreviation
Iatrogenic  Iatro 
Infective  Infec 
Non-A.L. leukaemia  OLeuk 
Second neoplasm  Neop2 
Heart  Heart 
Thrombotic or embolic  ThEmb 
Other vascular  OVasc 
Extraneous cause  Extra 
Not 1 - 8 and not A.L.L. NotAL 
10  Not A.L.L.  NotAL 
11  A.L.L.  ALL 
12  Unascertainable cause  Unkn. 
13  Haemorrhage  Haem 
14  Hypoplasia  Hypo 
15  Pneumonitis  Pnmit 
16  Effusion  Effu 
17  Pneumonia  Pneum 
18  Cytomegalovirus infection  CMV 
19  Adenoviral sepsis  ADVs 
20  Kidney failure  KidnF 
21  Pancreatitis  Pancr 
22  Meningitis  Menin 
23  Acute myeloid leukaemia  AML 
24  Sepsis  Sepsi 
25  Encephalitis  Encts 
26  Hepatitis  Hepat
27  Enterocolitis  Entco 
29  Liver failure  LivFa 
30  Encephalopathy  Encpy 
31  Ataxia telangiectasia  AtaxT 
32  Ascites  Ascite 
33  Perforation of colon  PerfC 
14  Name (if given), cause of death and comments  81 - end  Name
Missing or unknown items are left blank or set to zero.

ALLC 1992 data form rubric





Date of 1st complete remission

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[End of document, updated to 1 September 2000]