Ed Cadman

Schedule-dependent cytotoxicity of methotrexate and 5-fluorouracil in human colon and breast tumor cell lines.

The effect of sequential methotrexate and 5-fluorouracil on the clonal growth of the human colon adenocarcinoma cell, HCT-8, and the hormone-dependent human breast carcinoma cell, 47-DN, was examined. In both cell lines, when 5-fluorouracil was given during the last 6 h of a 24 h methotrexate exposure period, there was marked synergistic inhibition of clonal growth. Shorter intervals or the reverse sequence of drugs were either additive or antagonistic. These results indicate the importance of the drug sequence and time interval between drug administration for optimal cytotoxicity in these human cell lines. This information suggests that the administration of methotrexate 18 h before 5-fluorouracil may have potential application in the design of clinical trials for these malignancies.

Pulmonary metastases in ovarian cancer analysis of 357 patients

The pattern of pulmonary involvement from ovarian cancer was evaluated in 357 patients who were seen at the Yale‐New Haven Hospital from 1966 to 1975. Thoracic involvement by tumor was found in 169 patients (44.5%), a figure considerably higher than in previous reports. Pleural effusions were present in nearly 75% of patients who had thoracic involvement. Only 73% of the effusions contained identifiable malignant cells. Solid metastases to the pulmonary parenchyma were present in 12.3% of the patients; lymphangitic and nodal spread was observed in only 1% of the patients. The incidence of metastases did not correlate with tumor histologic features. Five‐year survival figures were 29% for the control group; 5.6% of the patients who had evidence of thoracic involvement were alive after 5 years compared with a 49% 5‐year survival of those patients with no evidence of thoracic involvement. Right‐sided lesions produced thoracic metastases more frequently than left‐sided lesions. No significant differences with respect to age, race, menopause, smoking history, or autopsy rate were found between those patients with and without pulmonary metastasis. Chest x‐ray was found to be of great value in determining pulmonary metastasis; only 6% of patients who were proven by autopsy to have spread of cancer to the thoracic cavity had a chest x‐ray that did not show malignancy. The majority of these ten patients had lymphangitic or microvascular disease. No cases of second primary occurring in the lung were noted in this review, although two case reports have appeared in the literature. Only three patients with pulmonary involvement by tumor had no other evidence of Stage IV disease.

Preliminary report on the efficacy of sequential methotrexate and 5‐fluorouracil in advanced breast cancer

Recent in vitro and animal tumor studies suggest that sequential methotrexate (MTX) and 5‐fluorouracil (5‐FU) may be much more tumoricidal than either drug when used alone or in conventional combinations. Seventeen evaluable female patients with advanced carcinoma of the breast were treated with MTX 200 mg/M2 I. V. followed one hour later with 5‐FU 600 mg/M2 I. V. Leucovorin 10 mg/M2 was begun orally 24 hours later and continued every six hours for six doses. Thirteen of these patients had not responded to prior drug treatment. Of the 17 patients, 11 responded to therapy, 9 had an objective response of greater than 50% tumor regression, and 2 had a minimal response of less than 50% tumor regression. The greatest number of responses was seen in skin and soft tissue. Disease‐free interval, hormonal status, and prior therapy, with the exception of MTX and 5‐FU containing drug regimens, did not appear to affect response rates. Toxicity was minimal and not life threatening. Based on these results it is believed that larger trials with this drug sequence are warranted.

The usefulness of the Lukes-Collins classification in identifying subsets of diffuse histiocytic lymphoma responsive to chemotherapy.

Twenty‐nine patients with Stage III and IV diffuse histiocytic lymphoma (DHL) were treated prospectively with cyclophosphamide, hydroxydaunorubicin, vincristine, prednisone and bleomycin (CHOP‐B) or hydroxydaunorubicin, cyclophosphamide, vincristine, methotrexate with leucovorine rescue and cytosine arabinoside (ACOMLA). Twenty‐six evaluable patients were reclassified blindly by the Lukes‐Collins classification with five large noncleaved follicular center cell (FCC), six large cleaved FCC, three large cell unclassified, seven B‐immunoblastic sarcoma and five T‐immunoblastic sarcoma patients identified. There was no significant survival advantage between the two combination chemotherapy programs. Survival of the immunoblastic sarcoma patients was inferior to that of the FCC lymphoma patients (P = 0.02). There were no significant survival differences between the large cleaved FCC and noncleaved FCC subtypes. Immunoblastic sarcomas, B‐ and T‐cell types, appear to be more resistant to standard combination chemotherapy programs and new approaches may warrant more aggressive therapy in future protocols. The large cell FCC lymphomas have an excellent prognosis.

Enhancement of 6-thioguanine cytotoxic activity with methotrexate

Abstract Studies were completed to characterize the cytotoxic and biochemical interaction of methotrexate (MTX) and 6-thioguanine (6-TG). Pretreatment of L1210 leukemia cells for 3 hr with MTX substantially enhanced the cytotoxicity of 6-TG. The LD90 of 6-TG in cells pretreated with 1μM MTX was 0.9pM, compared to an LD90 of 800 pM when the two drugs were given concurrently and an LD90 of 30 pM resulted with 6-TG alone. HPLC analysis of intracellular metabolites demonstrated an increased conversion of 6-TG to 6-TG-nucleotides in cells pretreated with MTX. A marked enhancement of 6-TG incorporation into RNA also was noted (MTX→6-TG: 350 fmol/μg RNA vs 6-TG: 98 fmol/μg RNA). However, there was a suppression of 6-TG incorporation into DNA when cells were pretreated with MTX (MTX→6-TG: 170 fmol/μg DNA vs 6-TG: 690 fmol/μg DNA). These results suggest that: 1) an enhancement of 6-TG antileukemic activity can be obtained with MTX pretreatment, and 2) the enhancement of 6-TG cytotoxicity following MTX exposure is not associated with 6-TG incorporation into DNA, but rather with incorporation of 6-TG into RNA. This drug sequence may be beneficial in the clinical treatment of leukemia.

Uridine and cytidine metabolism following inhibition of de novo pyrimidine synthesis by pyrazofurin

Pyrazofurin, an inhibitor of orotidylate decarboxylase, imposes an absolute nutritional requirement for exogenous uridine to maintain normal growth of L5178Y, P388, L1210, W256 and S180 cells in vitro. The amount of uridine necessary for cell division when de novo uridine nucleotide synthesis is inhibited by pyrazofurin is: L5178Y, 30.5; P388, 39.7; L1210, 53.3: W256, 70.6; and S180, 886 fmol/cell. Cytidine, which can be deaminated to uridine, will substitute for uridine to maintain normal cell growth in the presence of growth-inhibitory concentrations of pyrazofurin (5 microM). The requirements for cytidine and uridine are identical. If cytidine deamination is prevented by tetrahydrouridine (100 microM), cytidine can no longer support growth in the presence of pyrazofurin. Cytidine and uridine, as expected, are additive in their effect to permit normal growth of pyrazofurin treated cells. Tetrahydrouridine does not alter this additive effect, indicating that when both nucleotides are added to pyrazofurin treated cells each nucleotide replenishes their respective nucleotide pools and cytidine deamination is unnecessary to allow cell growth. Incorporation of [14C]uridine into the acid insoluble cell fraction of L5178Y cells was 25 fmol/cell at 48 h and remained constant during the remaining growth of the pyrazofurin treated cell suspension. The [14C]uridine acid soluble pool of 4 fmol/cell also was maximum at 48 h but declined during the subsequent growth of the suspension culture to approx. 2 fmol/cell at 96 h. This decline in the acid soluble pool is correlated with a 42% decrease in modal cell volume during this phase of cell growth which would maintain a constant specific activity of uridine in this pool. This may explain the decline in the acid soluble pool while the acid insoluble pool remains constant during growth of suspension cultures of L51878Y cells. The block in pyrimidine synthesis de novo induced by pyrazofurin provides a useful and quick method for the evaluation of uridine and cytidine metabolism of tumor cell specimens.

High-dose pulse chlorambucil. Effective therapy for rapid remission induction in nodular lymphocytic poorly differentiated lymphoma

Eighteen patients with Stage III or IV nodular poorly differentiated lymphocytic lymphoma (malignant lymphoma, infiltrative nodular type, with predominately small cleaved cells) were treated with intermittent high‐dose oral chlorambucil (16 mg/m2 daily for five consecutive days each month) for one year. Complete clinical remissions occurred in 78% of these patients and partial remissions in another 17%. Complete remission usually occurred within three months of beginning therapy and with a median followup of 35 months no patient has relapsed. Toxicity, usually hematologic and occurring late in therapy, has been mild, necessitating termination of therapy in only one patient. Review of recent therapy fails to demonstrate a definite long‐term advantage of more aggressive treatment regimens. Intermittent high‐dose chlorambucil should be further evaluated as therapy for nodular poorly differentiated lymphocytic lymphoma.

The effective use of combined modality therapy for the treatment of patients with Hodgkin's disease who relapsed following radiotherapy.

FROM 1969 TO 1977, 124 PATIENTS with advanced staged Hodgkins disease were entered into a treatment protocol which consisted of three cycles of drugs (nitrogen mustard, vincristine, vinblastine, prednisone, and procarbazine) followed by radiation (1500–2000 rad) to previous sites of known disease. After completion of radiation therapy, two more drug cycles were given. There were 63 newly diagnosed patients with Stage IIIB and IVA or B disease and 61 patients who had relapsed from prior radiotherapy. The median follow-up is now in excess of 5 years. Of the relapsed patients, 86.9% entered a complete remission and 90.6% of these patients have remained in complete remission from 1 to 10 years. In comparison, 81% of the newly diagnosed patients entered a complete remission and 78.4% of these patients continue free of disease from 1 to 11 years. These differences were not statistically significant. The 10-year actuarial disease-free survival—79.8% for the 61 relapsed patients compared to 65.6% for the 63 newly diagnosed patients—was not significantly different either. The 10-year actuarial survival for the 40 patients who had relapsed to IIIB and IVA or B was 71.3% and approximated more closely those of newly diagnosed IIIB and IVA or B patients. This drug-radiotherapy protocol is very effective for the treatment of patients who have relapsed from previous radiotherapy.

Chemotherapy of skeletal metastases

INTRODUCTION Metastatic cancer to bone is the most common bone cancer,23 unlike primary bone tumors, occurs at multiple sites 90% of the time.13 The axial skeleton is most often affected; the extremities rarely. Neoplasms of the breast, lung, prostate, kidney and thyroid account for nearly 80% of bone metastases. Skeletal metastases from the colon, pancreas and stomach are uncommon, occurring in less than 10% of patients with these tumors.‘.‘333 Radiographic appearance of the bone metastases aids in the identification of the primary source. Osteoblastic lesions in males most frequently will be of prostatic origin, rarely from pancreas, colon, lung, carcinoid tumor, Hodgkin’s disease, or myeloma. _41though the majority of skeletal breast lesions are lytic, the most common source of blastic bony metastases in women is breast cancer. Lytic bone lesions generally are without characteristic identifying features which would help in the identification of the primary cancer, with the exception of kidney, which often presents as a solitary radiolucent expansile bone lesion. Radiotherapy is the treatment of choice for skeletal metastases which are painful and few in number or located in strategic areas of skeletal support. However, many bone lesions, can be expected to respond favorably to chemotherapy. The effectiveness of chemotherapy on various skeletal metastases is reviewed. THYROID Thyroid carcinomas characteristically have many long term survivors following surgical therapy, 80-90% live 10 years or greater. The small number that succumb to ‘their disease often have bone or pulmonary metastases or both.1%1834 Papillary carcinoma occurs in approximately 66% of patients and tends to metastasize to local lymph nodes. Follicular carcinoma occurs in 20% of patients with a predilection for vessel invasion and subsequent bone and lung metastases. Treatment other than surgery has resided consistently with oral 13’1 administration. The dose is generally lOO-300mCi given repeatedly over 2 years for a total dose of 500 mCi.” I31 I has been documented to accumulate in bone metastases and to have a favorable effect on survival. In one study, all of 10 patients lived 5 years, with 3 patients living 6, 15 and 25 years after ‘9 therapy.” There is even documentation of roentgenograms returning to normal in 5 of 30 patients, with total regression of pain in all patients.” Other chemotherapeutic agents used in metastatic thyroid cancer without success are 5-fluorouracil, methotrexate, actinomycin D, cyclophosphamide, phenylaline mustard, and others.” The use of bleomycin has had conflicting reports.‘6 Adriamycin (75 mglm’ q3 week) achieved 4 partial remissions in 12 patients with bone involvement, it was documented as 50% radiographic regression for 1 month. One patient had relief of pain.‘O 13’1 appears to be the agent of choice when metastases are small and capable of concentrating 1311. Thus far, adriamycin is the only chemotherapeutic agent shown to be effective in advanced bone metastases.

Toxicity of Chemotherapeutic Agents

Effective chemotherapeutic agents are limited in their clinical use by the effects they produce on normal cells. The ratio of the doses at which therapeutic effect and toxicity occur is referred to as the therapeutic index. Ideally, one would like to have at his disposal drugs that have a higher therapeutic index, i.e., maximum therapeutic benefit with virtually no toxicity. But since this ideal situation has not been achieved, we must remain cognizant of the various toxicities of the chemotherapeutic drugs so that these agents can be used as effectively as possible. Each drug has unique antitumor properties and, as would be expected, unique toxicities. Some toxicity is acute, some delayed, but it is always present. This chapter is a review of these toxicities.