Drug-induced cancer

Oral squamous cell carcinoma following treatment of acute lymphoblastic leukaemia

With substantially increased survival after most paediatric cancers over the past decades have come the late sequelae of treatment. Of all late complications of treatment, second malignancies are generally considered to be the most serious. We report on a 20-year-old man with an oral squamous cell carcinoma 17 years after initial chemotherapy and irradiation for acute lymphoblastic leukaemia. Although occurrence of the oral malignancy in this patient could have been treatment-related, one should keep in mind that the occurrence of second tumours may also be based on a shared genetic aetiology.

Cutaneous angiosarcoma as a second malignant neoplasm after peripheral primitive neuroectodermal tumor

Second malignant neoplasms (SMN) in late childhood or young adulthood in individuals who have been successfully treated for an initial malignancy have emerged as a late effect of therapy in survivors of childhood cancer. Although radiation therapy is frequently implicated, chemotherapy with alkylating agents and antimetabolites has also been associated with SMN. Soft tissue sarcomas are among the most frequent primary malignancies complicated by a SMN and account for a majority of nonhematolymphoid SMN. We present the clinical and pathologic findings in a patient who had a peripheral neuroepithelioma (primitive neuroectodermal tumor, PNET) of the soft tissues diagnosed at 17 years of age, was treated with high-dose irradiation and multidrug chemotherapy, and developed an angiosarcoma 14 years later. This case represents an uncommon combination of mesenchymal malignancies in a young patient with an unusually favorable clinical course following the diagnosis of PNET.

Mucoepidermoid carcinoma of the parotid as a second malignant neoplasm in children

Second malignant neoplasms (SMN) in children who have survived their initial encounter with a malignancy have emerged as one of the most troublesome complications in pediatric oncology. Some estimates indicate that as many as 8% to 12% of patients will develop a SMN during a 20-year period. The majority of SMN are osteosarcomas, spindle cell and pleomorphic sarcomas of soft tissues, and hematolymphoid malignancies. We present the clinical and pathologic findings for two children with treated acute leukemias in whom well-differentiated mucoepidermoid carcinomas of the parotid gland developed 6 and 9 years after multidrug chemotherapy and cranial irradiation. Although mucoepidermoid carcinoma has been reported as a complication in adults who received low-dose irradiation as children, these two cases are unique as SMN in the pediatric age population.

In vitro activation of isophosphamide and trophosphamide to metabolites mutagenic for bacteria

The ability of S9 liver fractions from uninduced rats to activate isophosphamide (IP) and trophosphamide (TP) to metabolites mutagenic for bacteria was compared to that of S9 fractions prepared from rats pretreated in vivo with three inducers of hepatic monooxygenase. Pretreatment of rats with phenobarbital (PB) and Aroclor 1254 increased IP and TP mutagenic activation by S9 fractions as compared to control and 3-methylcholanthrene (3-MC)-induced rat liver S9. Furthermore, the effect of mixed-function oxidase inhibitors, such as alpha-naphthoflavone, metyrapone and SKF 525-A on S9-mediated mutagenic activation of IP and TP was investigated. The data obtained suggest the involvement of a PB-inducible form of cytochrome P-450 in the activation of IP and TP to mutagenic species.

Second neoplasms in acute lymphoblastic leukemia

The authors reviewed 61 reported cases of second neoplasms in acute lymphoblastic leukemia (ALL), including 17 patients with ALL followed by another type of acute leukemia, 12 patients with ALL followed by chronic myelocytic leukemia, 19 patients with ALL followed by lymphoma, and 13 patients with ALL followed by other solid tumors. From a review of the literature, it is believed that there is no firm evidence yet that patients with ALL, intensively treated with chemotherapy and/or radiotherapy, are at increased risk of developing therapy-related second neoplasms. Because the number of cases reported is small, there is even insufficient data to firmly suggest that acute myeloblastic leukemia, following intensive therapy for ALL, occurs in a higher-than-expected frequency.

Prevention of urinary bladder tumors in cyclophosphamide-treated rats by additional medication with the uroprotectors sodium 2-mercaptoethane sulfonate (mesna) and disodium 2,2'-dithio-bis-ethane sulfonate (dimesna)

Cyclophosphamide (CP) was administered orally at a dose of 2.5 mg/kg body weight five times a week to 300 male Sprague-Dawley rats in a carcinogenicity experiment. Four groups of 50 rats were treated with two different doses of sodium 2-mercaptoethane sulfonate (mesna, Uromitexan) (single doses of 5 or 15 mg/kg body weight), or disodium 2,2'-dithio-bis-ethane sulfonate (dimesna) (single doses of 12 or 35 mg/kg body weight), and the effect on carcinogenicity by cyclophosphamide was investigated. Two groups received mesna or dimesna only, and one additional group of 100 rats served as an untreated control. Evaluation of the study after 20 months proved CP to be carcinogenic, the induced neoplasms being in a variety of organs including tumors of the urinary bladder in 30% of the rats. The additional administration of mesna and dimesna significantly reduced the bladder tumor risk, this reduction being dose-related. In the 100 rats treated with mesna or dimesna only, no evidence of a carcinogenic response or signs of other toxic effects were observed.