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Dose-dense chemotherapy increases the dose intensity of the regimen by delivering standard-dose chemotherapy with shorter intervals between the cycles. This article discusses the rationale for dose-dense therapy and reviews the results with dose-dense adjuvant regimens in recent clinical trials in breast cancer.The papers for this review covered evidence of a dose-response relation in cancer chemotherapy; the rationale for dose-intense (and specifically dose-dense) therapy; and clinical experience with dose-dense regimens in adjuvant chemotherapy for breast cancer, with particular attention to outcomes and toxicity.Evidence supports maintaining the dose intensity of adjuvant chemotherapy within the conventional dose range. Disease-free and overall survival with combination cyclophosphamide, methotrexate, and fluorouracil are significantly improved when patients receive within 85% of the planned dose. Moderate and high dose cyclophosphamide, doxorubicin, and fluorouracil within the standard range results in greater disease-free and overall survival than the low dose regimen. The sequential addition of paclitaxel after concurrent doxorubicin and cyclophosphamide also significantly improves survival. Disease-free and overall survival with dose-dense sequential or concurrent doxorubicin, cyclophosphamide, and paclitaxel with filgrastim (rhG-CSF; NEUPOGEN) support are significantly greater than with conventional schedules (q21d).The delivered dose intensity of adjuvant chemotherapy within the standard dose range is an important predictor of the clinical outcome. Prospective trials of high-dose chemotherapy have shown no improvement over standard regimens, and toxicity was greater. Dose-dense adjuvant chemotherapy improves the clinical outcomes with doxorubicin-containing regimens. Filgrastim support enables the delivery of dose-dense chemotherapy and reduces the risk of neutropenia and its complications.

(1993). O6-Methylguanine-DNA Methyltransferase in Human Normal and Malignant Lung Tissues. Cancer Investigation: Vol. 11, No. 3, pp. 258-263.

Eighty-six eligible patients with non-small cell lung cancer were treated on a Phase II, CALGB study with high-dose, 24-h continuous intravenous 5-fluorouracil every 2 weeks. Objective responses were seen in 7 (8%) patients with 1 (1%) complete response and 6 (7%) partial responses. The median survival for these patients without prior chemotherapy was 3.8 months. Gastrointestinal and hematologic toxicity were acceptable for most patients. However, two patients experienced acute clinical deterioration characterized by worsening central nervous system and hemodynamic function beginning near the completion of chemotherapy treatment and resulting in death. Because of its potential for severe, unpredictable neurologic and cardiac toxicity, we do not recommend this dose and schedule of 5-FU for future trials.

Eleven morphine naive patients with cancer-related pain were given a single dose of either intravenous morphine (n = 5) or oral morphine (n = 6). Blood sampling was performed over a 24-hr period and serial pain assessments were made using a categorical scale. Plasma samples were analyzed for morphine, morphine-6-glucuronide (M-6-G), morphine-3-glucuronide (M-3-G), and normorphine using high-performance liquid chromatography. In neither the intravenous nor oral group was there a correlation between analgesia duration and the half-lives of morphine and M-6-G. There was no correlation between the time to peak analgesia and time to peak concentration for morphine or M-6-G. There was no significant difference in absolute concentrations of M-6-G or M-3-6 nor in the ratio of M-3-G to M-6-G at peak analgesia versus relapse.

The effect of high-dose leucovorin on 5-fluorouracil (5-FU) pharmacokinetics was studied in 5 patients with metastatic colorectal carcinoma. Patients received leucovorin, 500 mg/m2, and 5-FU, 600 mg/m2, on 1 day and 5-FU alone 1 week later. Plasma concentrations of 5-FU and 5-FU anabolites were determined over 2 hr. Levels of 5-FU were highest initially and then fell rapidly. Plasma concentration-time curves suggested a two-compartment kinetic model. Anabolite levels exceeded 5-FU levels after 15 min. When leucovorin was administered, the time of distribution (t1/2 alpha for 5-FU increased from 8.9 +/- 2.4 to 12.8 +/- 2.5 min (p0.0005) and the volume of distribution (Vd) increased from 0.129 +/- 0.039 to 0.237 +/- 0.033 L/kg (p0.03). Elimination and plasma clearance of 5-FU were unchanged. Anabolite levels were initially lower (p0.05) with leucovorin, suggesting increased tissue extraction of 5-FU.

An important component of high-dose chemotherapy/autologous bone marrow support regimens for adjuvant treatment of breast cancer is carmustine. Preclinical studies have shown that the level of the DNA repair protein O6-methylguanine-DNA methyltransferase is correlated with the resistance of cultured human tumor cells to this drug, but little is known about transferase levels of breast tissue in vivo. We measured the DNA repair activity in 80 tissue samples from 65 patients, including normal, abnormal, benign, and malignant specimens. Wide interindividual variations was observed and average transferase levels were similar in normal and benign tissue. However, transferase levels were significantly elevated in stage I-IV disease. In addition, the frequency of samples with no detectable transferase was greatly reduced in this malignant group, and transferase was positively correlated with the presence of positive nodes, a marker for disease progression. In contrast, transferase levels were not correlated with age or estrogen receptor status, and the levels in normal tissue did not vary between patients with benign or malignant disease. These results suggest that this DNA repair activity may be increased in breast cancer relative to normal tissue and encourage further study of the predictive value of transferase measurements in high-dose chemotherapy/autologous bone marrow transplant for breast cancer.

The safety and efficacy of patient-controlled analgesia for the long-term control of cancer pain was tested prospectively. Respiratory rates, mental status, and pain relief were recorded at baseline and compared with those during the study period. Patients had a lower analgesic demand (i.e., self-administered less morphine during the nighttime); specifically, dosing declined 48% from the daytime level. Respiratory rates did not change appreciably during the study and no cases of significant respiratory depression were encountered. Patients self-administered sufficient morphine to produce adequate but not complete pain relief in almost all trials. Pain relief was safely achieved by both intravenous and subcutaneous routes of administration in both the inpatient and outpatient settings. Mean 24-h morphine use stayed relatively constant even for patients receiving more than 2 weeks of treatment. In conclusion, patient-controlled analgesia is effective and safe therapy for the long-term control of severe cancer pain.