Retreatment of chronic hepatitis C virus infection

those with slowly growing tumours of the same size (even when the former receives a more effective treatment in terms of cell kill). In practice, the sizes of subclinical metastases at primary diagnosis present different and undefinable starting points. They then grow at different rates and have different responses to drugs. The randomisation of breast cancer patients in trials that record survival or time to recurrence as endpoints, and that take the purely arbitrary date of first attendance as their starting point is surely illogical. Improvement in diagnostic techniques may solve part of the difficulty but much more observational data about individual tumour behaviour is also needed. Neoadjuvant therapy can provide the opportunity for such measurement; it also allows the treatment to be tailored to the individual, rather than to be assigned randomly, so that ineffective drugs can be abandoned. Prognostic factors can be directly related to clinical response. Why should diversion of funds to such therapeutic investigations be "rank foolishness"? Ann E Johnson Breast Study Centre,

Mount Vernon

Hospital, Northwood,

Middlesex HA6 2RN, UK

1 Johnson AE, Cheung CWD, Cox SJ, Sales JEL. Tailoring treatment to individual tumours: why randomised clinical trials cannot do this for breast cancer. Presented at Lancet Conference: the challenge of breast cancer, Brugge, Belgium, April 21, 1994. London: The Lancet, 1994: 71. 2

Cheung CWD, Johnson AE. Carcinoma of the breast: measurement and the management of treatment, II: The regression of tumours. Br

lung cancer, failed to respond to warfarin anticoagulation and also lacked evidence for tumour-cellassociated thrombin generation.1 small-cell

Breast cancer may now be added to the list of tumour types that are unresponsive to warfarin. Correspondingly, breast cancer cells also show no evidence of tumour-cellassociated thrombin generation in situ. Rather, these cells express urokinase3and its receptor’ which have been implicated in growth promotion of breast cancer.1,3 Levine and associates’ results corroborate our hypothesis and draw attention to the potential importance of testing experimental intervention aimed at inhibition of urokinase in this common tumour type. Simultaneously, because thrombin can enhance tumour growth by several mechanisms, there is reason to speculate that the partial beneficial effects recorded with warfarin and heparin therapy of SCCL may be improved further by treatment with more potent and specific inhibitors of blood coagulation (such as hirudin, antistatin, low-molecular-weight heparin) that have become available. This treatment concept may be worthy of investigation not only in SCCL but also in renal cell carcinoma,’ malignant melanoma,’ and ovarian carcinoma,’ which also express tumour-cell-associated thrombin generation in situ. Leo R Zacharski Department of Veterans Affairs, Medical and Regional Office Center, White River Junction, VT 05009, USA

J

Radiol 1991; 64: 121-32. 1

Warfarin treatment in breast

2

cancer

SIR-Levine and colleagues (April 9, p 886) report in a prospective, randomised, double-blind trial the safety and efficacy of low-dose warfarin for prevention of thromboembolism in women receiving chemotherapy for advanced breast cancer. They comment that warfarin had no effect on the natural history of breast cancer in their study by

3

with observations in small-cell carcinoma of the lung (SCCL, see their ref 27). The absence of effect of warfarin on survival in breast cancer may not be as attributable to an inadequate dose of warfarin or duration of therapy as they suggest. In our original study in SCCL, the prothrombin time was prolonged only to a mean of about 18 s (the international normalised ratio was not available at that time) and the duration of therapy was only about half the total survival time. Despite these limitations, a significant improvement in survival was recorded in patients with SCCL that could only be attributed to the fact that they had been randomised to receive warfarin.’ We believe that there may be another explanation for this difference. Three prospective randomised trials of warfarin and one of subcutaneous unfractionated heparin have shown a statistically significant improvement in survival in patients with SCCL given these anticoagulants.1,2 We postulated that, for an anticoagulant to influence the behaviour of tumour cells, the products of coagulation activation (for example, thrombin) would probably exist in the immediate vicinity of the tumour cells in situ. We have examined SCCL tumour tissues with immunohistochemical techniques and recorded tumour-cell-associated thrombin generation manifested by tumour-cell expression of components of coagulation factor pathways, thrombin-antithrombin complex neoantigen, activated factor X, and thrombin (with active site-specific probes for these activated enzymes), and conversion of fibrinogen to fibrin adjacent to individual SCCL tumour cells and tumour nodules.1,2 By contrast with SCCL, several other tumour types, including colon, prostate, and non-

5

contrast

1568

4

Zacharski LR, Wojtukiewicz MZ, Costantini V, Ornstein DL, Memoli VA. Pathways of coagulation/fibrinolysis activation in malignancy. Semin Thromb Hemost 1992; 18: 104-16. Lebeau B, Chastang CL, Brechot JM. Subcutaneous heparin treatment increases complete response rate and overall survival in small cell lung cancer (SCLC). Lung Cancer 1991; 7 (suppl): 129. Costantini V, Zacharski LR, Memoli VA, et al. Occurrence of components of fibrinolysis pathways in situ in neoplastic and nonneoplastic human breast tissue. Cancer Res 1991; 51: 354-58. Zacharski LR, Barnathan ES, Memoli VA, Rousseau SM. Comparison of four antibodies for immunohistochemical detection of urokinase receptor (U-PAR) in tissue. Thromb Haemost 1993; 69: 1234.

Zacharski LR, Ornstein DL, Memoli VA, Kisiel W, Rousseau SM. Tumor cell procoagulant and urokinase expression in carcinoma of the ovary. J Natl Cancer Inst 1993; 85: 1225-30.

Retreatment of chronic infection

hepatitis C virus

SIR-Treatment of chronic hepatitis C virus infection with interferon-a induces a response in 50% of cases, but most patients relapse.1,2 To improve these results, several cycles of treatment may be given. We treated 126 patients (31 females, mean [SD] age 44 [14] years) with two cycles of interferon-a and 25 with a third, because they did not respond or responded but relapsed to a previous interferon-a

cycle. All

had abnormal alanine aminotransferase values for over 1 year and a type of chronic hepatitis C virus infection (73 chronic active hepatitis, 10 chronic persistent hepatitis, 7 liver cirrhosis, 36 no liver specimen taken). None had HIV infection, and other causes of liver disease were excluded. During the first cycle, patients were treated with interferon-a (2a, 2b, or lymphoblastoid), and all received at least 3 MU three times per week for 6 months (mean total dose 277 MU, range 216-864, during a mean of 8 months, range 6-14). 6 months or more after treatment, they received a second cycle of interferon-a (336 MU, 216-864) for a mean of 7 months (6-12). Finally 25 of these patients were treated with a third cycle (638 MU, 216-996) for a mean of 9-5 months (6-14).

(ALT)

patients

individuals. Only after oral intake of huge of methionine (6 g), very small amounts of methyl mercaptan appeared in the breath of healthy individuals during the first 30 minutes after methionine intake.After that time, methyl mercaptan disappeared and an increase in breath dimethylsulphide was noted. By contrast with methyl mercaptan, dimethylsulphide is a neutral molecule and is stable in whole blood. This is the main reason why dimethylsulphide is the only sulphur compound present in the breath of healthy individuals and of those with cirrhosis. cirrhotic

amounts

*Responders vs non-responders, p<0.05 (ttest). Table: Results of retreatment

During the first cycle of interferon-a, 44 of 126 (35%) patients responded (ALT values returned to normal), but relapsed at the end of treatment. In the second cycle, 54 of 126 (43%) responded, but all relapsed at the end of treatment. Most (89%) of the patients who responded to the first cycle did so in the second cycle. A similar trend was observed in non-responders in whom 90% did not develop normal ALT values during both cycles. Significant differences between responders and non-responders to both cycles were observed with respect to age, total dose, and therapy duration in each cycle of treatment (table). Responses after a third cycle were similar to those achieved in previous cycles. Thus 8 of 25 patients responded to all cycles and 16 of 25 were non-responders to all interferon-a cycles. 1 patient (4%) responded only to the third cycle. All patients again relapsed after the third cycle. Treatment responses in each cycle took place within 3 months of the start of therapy in 95% of the patients. We conclude that

with interferon-a of nonresponders, relapse, does not induce a responders long-term response. Most patients who do or do not respond to a cycle of interferon-a will behave similarly in other cycles of treatment. For these reasons, additional cycles of interferon-a should be attempted only for patients who have retreatment

with

or

responded to previous cycles. Margarita Pardo, Eduardo Marriott, Vicente Carreño

Teresa Cotonat, Montserrate Herrero, Santiago Artillo, Juan Antonio Quiroga,

Hepatology Unit, Fundación Jiménez Díaz, 28040 Madrid, Spain

Davis GL, Balart LA, Schiff ER, et al. Treatment of chronic hepatitis C with recombinant interferon alpha: a multicenter randomized, controlled trial. N Engl J Med 1989; 321: 1501-06. 2 Di Bisceglie AM, Martin P, Kassianides C, et al. Recombinant interferon alpha therapy for chronic hepatitis C: a randomized, double-blind, placebo-controlled trial. N Engl J Med 1989; 321: 1506-10. 1

Foetor hepaticus SiR-In response to our findings that dimethylsulphide is the principal component of foetor hepaticus (Feb 19, p 483), Walshe claims that methyl mercaptan is the main component (March 19, p 730). However, Challenger and Walshe’ were unable to measure the volatile components in the breath of patients but measured only those in urine. We were also able to detect small amounts of methyl mercaptan, dimethylsulphide, and dimethyldisulphide in urine. However, foetor hepaticus is not caused by the odorous compounds in urine but by those in breath. The presence of methyl mercaptan in urine does not mean that it is also present in breath. In-vitro experiments2 have shown that methyl mercaptan is a highly reactive component and immediately reacts with whole blood, resulting in the formation of sulphate and formic acid; this is probably why methyl mercaptan is not present in the breath of healthy and

Albert

Tangerman,

Maria T Meuwese-Arends, Jan B M J Jansen

Division of Gastrointestinal and Liver Diseases, 6500 HB Nijmegen, Netherlands

1 2 3

University Hospital Nijmegen,

Challenger F, Walshe JM. Foetor hepaticus. Lancet 1955; i: 1239-41. Blom HJ, Tangerman A. Methanethiol metabolism in whole blood. J Lab Clin Med 1988; 111: 606-10. Tangerman A, Meuwese-Arends MT, van Tongeren JHM. A new sensitive assay for measuring volatile sulphur compounds in human breath by Tenax trapping and gas chromatography and its application in liver cirrhosis. Clin Chim Acta 1983; 130: 103-10.

Preimplantation diagnosis SiR-Cui and Matthews

(April 16, p 972) respond to our cautionary (Feb 26, p 549) on the use of the chain reaction (PCR) to co-amplify sequences polymerase for the identification of sex in preimplantation embryos by casting doubt on our results with fluorescent in-situ hybridisation (FISH). All techniques used by our group for preimplantation genetic diagnosis have been developed and extensively tested on human lymphocytes or fibroblasts and then applied to spare human embryos before diagnostic use. However, no amount of testing prepares one for the reality of the diagnostic situation, where every biopsied cell must be processed and there is no freedom to choose the best cells or embryos. It is highly unlikely that any technique will remain note

100% successful in this situation. Cui and Matthews claim that FISH is vulnerable to excess signal failure, but in our experience an experienced observer can easily distinguish specific from non-specific staining and normal DNA replication need not be a difficulty.’ Hybridisation failure may lead to a normal cell being classified as XO, but this would not cause misdiagnosis for if that were the only information available the embryo would not be transferred. By misquoting our FISH data your correspondents claim that only 10/26 embryos were useful for diagnosis because of "false" detection of mosaicism. The facts were that 7 embryos from one patient were unsuitable for biopsy, because of cell lysis; from four other patients 10 embryos were diagnosed as male and 8 as female, 4 of which had a normal XX cell and were transferred. The remaining 4 females were not used since they had one or more cells with abnormal numbers of X signals in the absence of a cell with the normal 2 Xs. 2 of these were confirmed as chromosomally abnormal by analysis of the remainder of the embryo; 1 was completely XO and the other showed evidence of mitotic non-disjunction.2 In a recent

(unpublished) diagnostic were

case, 9

gave three X

available; 6 normal XX. 1 cell and this was

embryos

male, but of the 3 females, only 1

were

was

signals in the biopsied confirmed as affecting the whole embryo by subsequent analysis. The third gave differing results in two nuclei within a single blastomere; again similar anomalies were detected in the remaining cells of the embryo. The important point is that, in all these 4 cases, the whole embryo was shown to be 1569