1121

RELATION BETWEEN FREQUENCY OF a-STREPTOCOCCAL SEPSIS ANDRADIATION DOSE TO ORAL CAVITY

-

TBI = total body irrad-iation; TLI = total lymphoid irradiation.*X!=6’1 (p<O’05).

contributor to a-streptococcal bacteraemia, and we are now

studying the effect of oral antisepsis on the incidence and severity ofmucositis and the incidence of a-streptococcal sepsis in patientsundergoing BMT.

Bone Marrow Transplantation Program,Departments of Pediatrics and Medicine,University of Minnesota,Minneapolis, Minnesota 55455 USA

BRUCE BOSTROMDANIEL WEISDORF

MALIGNANT MELANOMA IN PATIENT WHORECEIVED NEUTRON BEAM THERAPY

SIR,-Dr Waxler’s letter (April 21) suggests an adverse effect ofneutron therapy. A melanoma appeared on the left hand of a patientwho, 9 months previously, had received neutron therapy to the righthand. To assess this report the following data (not given) arerequired: the dimensions of the neutron beam, the position of thebeam in relation to the patient’s hands, the energy of the neutrons,and the technique used to immobilise the patient. The melanoma isdescribed as occurring "apparently on the periphery of the radiationfield". Even if Waxler meant to say that the melanoma appeared onthe right hand, this description is too vague. Only if the neutrondose to the site of the melanoma is calculated can this anecdote have

any clinical value. Did neutron therapy to the primary tumour avoidthe need for amputation of the right hand?Nine months is a very short time for any radiation-induced

tumour, and other factors, such as natural or artificial sunlight, maybe more relevant.Since the cyclotron at Hammersmith Hospital started being used

for neutron therapy 14 years ago, seventeen other centres

worldwide have offered this therapy, and to our knowledge noneutron-induced tumours have been seen. We have treated morethan 1500 patients (and about 3000 sites) and most of these patientshave been followed up for much longer than nine months. Neutrontherapy has resulted in complete regression in 71 &deg;70 of melanomas,with 5% recurrence rate, in patients followed up for more than threemonths.

Fast Neutron Clinic,MRC Cyclotron Unit,Hammersmith Hospital,London W12 0HS MARY CATTERALL

* This letter has been shown to Dr Waxler, whose replyfollows.-ED. L.

SIR,-There was an unfortunate error in my letter: the melanomaappeared on the left hand after neutron beam therapy to a synovialsarcoma on the left hand. Details of the neutron beam were:dimensions 6 x 10 cm, position horizontal, energy 66 MeV. The armof this cooperative patient was positioned by extending it on a chairwith the field of radiation on the left hand constant at eachtreatment. The malignant melanoma arose within a few millimetresof the edge of the field of radiation on the left hand.According to the radiotherapist (Dr S. Yalavarthi, Fermilab,

Batavia, Illinois) the patient has no clinical evidence of recurrenceor persistence of the synovial sarcoma (about 31/2 years after neutronbeam therapy to the mass).

I described this case to raise an interesting question and to alertphysicians to look for the possible association of malignantmelanoma as a low-incidence complication of neutron beam

therapy. I feel my letter will serve its purpose if other physicians

who see many patients after neutron beam therapy are encouragedto examine this question with definitive studies. My letter was notmeant to serve as such a study.Department of Pathology,Loyola University,Stritch School of Medicine,

Maywood, Illinois 60153, USA BEVERLY WAXLER

MANAGEMENT OF CONGENITAL ADRENALHYPERPLASIA

SIR,-We agree with Dr Anthony (May 12, p 1073) that height,weight, and bone age measurements and the use of growth charts areessential as the first line of assessment of adequate growth andcontrol of congenital adrenal hyperplasia (CAH). Biochemical testsare an adjunct to these measurements. We do not suggest thatcomplete suppression of 17-hydroxyprogesterone levels should beaimed for-indeed a figure of 20 nmol/1 blood (equivalent to about30 nmol/1 plasma) is given as an "acceptable" level. The data

presented in our March 31 paper were from a small group ofchildren who were being investigated for additional complicationsto their CAH. Most of our children with CAH are being treatedwith hydrocortisone which, we agree, is the optimal therapy for theyoung child. However, we do have three children in whom adequatesuppression did not occur on cortisone acetate but who wereadequately suppressed on prednisolone. The girl on dexamethasonewas a non-salt loser with a long history of excessive weight gain onseveral different steroid regimens (cortisone actetate, prednisolone,or hydrocortisone). A small dose of dexamethasone at night hasproved to be the best therapy to allow adequate growth and reducethe rate of weight gain. We did not intend to convey the impressionthat, in general, patients should be switched to dexamethasone inresponse to a deterioration in control; nevertheless there are

occasions when the use of steroids other than hydrocortisone orcortisone acetate is of value.

Chemical Pathology,Southampton General Hospitaland University of Southampton,

Southampton SO94XY

P. J. WOODP. BETTSB. E. CLAYTON

SIR,-The paper by Dr Riordan and colleagues highlights currentinterest in neonatal screening for CAH. These workers havedemonstrated the feasibility of a blood spot radioimmunoassay for170H-progesterone as a screening procedure. This method,however, required a time-consuming, expensive, and labourintensive solvent extraction step before assay and was applied toonly a small number of neonatal blood spot samples (491).A larger pilot study is in progress in the West of Scotland. The

solvent extraction step has been eliminated, greatly facilitating thescreening of large numbers of samples. The radioimmunoassaydeveloped for this purpose uses a specific high titre antibody to170H-progesterone which is encapsulated within semipermeablenylon microcapsules. So far 20 000 consecutive neonatal bloodspot samples have been analysed. The upper limit of normal is 75nmol/1 blood, and two cases of CAH were found to have very highlevels (much greater than 300 nmol/1). The false positive rate is

acceptable (I case to date ).The incidence of CAH in blood spot samples analysed so far is

thus 1:10 000. However, a larger sample is required before eitherthe true incidence of the disease or the contribution of neonatal

screening to health care can be accurately assessed.

Department of Clinical Chemistry,Glasgow Royal Infirmary,Glasgow G40SF

Neonatal Screening Laboratory,Stobhill Hospital, Glasgow

Duncan Guthrie Instituteof Medical Genetics, Glasgow

A. M. WALLACEG. H. BEASTALLA. M. ROSS

R. W. A. GIRDWOODR. KENNEDY

M. A. FERGUSON-SMITH

1. Wallace AM, Wood DA. Development of a simple procedure for the preparation ofsemipermeable antibody-containing microcapsules and their analyticalperformance in a radioimmunoassay for 17-hydroxyprogesterone. Clin Chim Acta(in press).