[Laboratory variables and stratification of small-cell lung cancer patients: recommendations for therapeutic trials and for clinical practice guidelines].
OBJECTIVE
To identify, through a systematic review of the literature, the laboratory variables that, in addition to performance status and to extent of the disease, would allow a more accurate stratification of small-cell lung cancer patients who participate in chemotherapy trials, with or without radiotherapy. Secondary aim: to compare the results of our systematic review with the recommendations made in current clinical practice guidelines.


METHODS
Update of two recently published systematic reviews, without meta-analysis, following the recommendations of the International Federation of Clinical Chemistry and Laboratory Medicine, and taking into account the Consolidated Standards of Reporting Trials statement.


RESULTS
Of 1143 publications retrieved, exclusion and inclusion criteria allow us to include 13 studies in our review. The three variables which were the most often found significant in multivariate statistical analysis, were: pre-therapeutic levels of laboratory variables (13/13), performance status (12/13), and degree of tumour invasion (10/10). Among the laboratory variables, serum lactate dehydrogenase (LDH) is the only one that was quite consistently found to be of independent prognostic significance, with p values or hazard ratios quite close to those obtained with performance status, or with extent of the disease. The recommendations made in the four clinical practice guidelines that we retrieved, are often vague regarding laboratory variables, and sometimes they even contradict each others.


CONCLUSIONS
Available evidence would support the recommendation that pretreatment LDH should be systematically measured in order to stratify patients in therapeutic trials. If other laboratory variables were to be measured in addition to LDH for this purpose, it seems that alkaline phosphatase (ALP), and to a lesser extent, sodium and white blood cell counts, might be the best suited ones. Nevertheless, further studies are necessary to more clearly support this latter recommendation. Available evidence would not support the measurement of any other laboratory variable in this context, before, during, or after treatment. Our recommendations are more in agreement with the recommendations made in the clinical practice guidelines that use evidence-based methods than with the guidelines that do not.
Watine
J
J
Laboratoires de biologie polyvalente des centres hospitaliers généraux de Rodez, France. j.watine@ch-rodez.fr
Friedberg
B
B
Charet
J-C
JC
D018288:Carcinoma, Small Cell / Q000175:diagnosis* / Q000628:therapy*; D019411:Clinical Laboratory Techniques; D002986:Clinical Trials as Topic; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000628:therapy*; D017410:Practice Guidelines as Topic