Recent Advances in Cancer Chemotherapy

The present state of cancer chemotherapy can be reviewed in light of selected basic principles with an acknowledgement of the role of established chemotherapeutic agents. Four chemotherapeutic agents recently approved for clinical use and their impact when used in combination regimens should be examined. Several important concepts influencing chemotherapy in the 1980s include the use of chemotherapy in the adjuvant setting, the use of hormonal receptor data in planning therapy, and the use of in vitro tests on tumor specimens to predict tumor sensitivity to cancer chemotherapy drugs (prior to administration of these potentially toxic drugs to a particular patient). Lastly the reader is cautioned about the potential of long-term complications with certain chemotherapy agents, especially in those patients who have had complete or extended partial remissions

Genetics and Cancer

The existence of a relationship between cancer and heredity has been recognized for years, but only recently has emerging knowledge in this area enabled physicians to detect and treat cancer earlier in affected individuals and to prevent its occurrence in others

DIHYDROPYRIMIDINE DEHYDROGENASE DEFICIENCY (DPD) IN GI MALIGNANCIES: EXPERIENCE OF 4-YEARS

ABSTRACT Objectives: 5-Fluorouracil (5-FU) is an integral part of treatment of GI malignancies. While normal DPD enzyme activity is rate limiting in 5-FU catabolism, its deficiency could increase concentrations of bioavailable 5-FU anabolic products leading to 5-FU related toxicity syndrome. Methodology: Twenty-three patients were tested for DPD deficiency after excessive toxicities from 5-FU and/or capecitabine. DPD activity was evaluated by Peripheral Blood Mononuclear Cell (PBMC) radioassay, genotyping of DPYD gene by Denaturing High Performance Liquid Chromatography (DHPLC), or 2-13 C uracil breath test (UraBT). Results: Of 23 patients with excessive toxicities from 5-FU and/or capecitabine, 7 (30%) were DPD deficient with a median age of 66 years, M:F ratio = 1.3:1 and ethnicities included Caucasian (71%), African-American (14%) and South-Asian (14%). DPD activity ranged from 0.064 -0.18nmol/ min/mg. Three patients were treated with bolus 5-FU/LV, two with capecitabine, and two with high dose bolus 5-FU with 2', 3', 5'-tri-O-acetyluridine. Toxicities included mucositis (71%), diarrhea (43%), skin rash (43%), memory loss/altered mental status (43%), cytopenias (43%), nausea (29%), hypotension (14%), respiratory distress (14%) and acute renal failure (14%) Re-challenge with capecitabine in one patient after the Mayo regimen caused grade 3 hand-foot syndrome. Genotypic analysis of the DPYD gene in one patient with severe leucopenia demonstrated a heterozygous mutation (IVS14+1 G>A, DPYD). The UraBT in two patients revealed 1 to be DPD-deficient (DOB 50 of 112.8; PDR of 49.4%) and borderline normal values (DOB 50 of 130.9; PDR of 52.5%) in a second patient. There were 2 toxicity-related deaths among DPD-deficient patients (28%). Conclusions: DPD deficiency was observed in several ethnicities. Akin to 5-FU, capecitabine can also lead to severe toxicities in DPD-deficient patients. Screening patients for DPD deficiency prior to administration of 5-FU or capecitabine using UraBT could potentially lower risk of toxicity. Future studies should validate this technique

Treatment of Cryptococcal Meningitis with Combination Amphotericin B and Flucytosine for Four as Compared with Six Weeks

Abstract One hundred ninety-four patients with cryptococcal meningitis were enrolled in a multicenter, prospective, randomized clinical trial to compare the efficacy and toxicity of four as compared with six weeks of combination amphotericin B and flucytosine therapy. Among 91 patients who met preestablished criteria for randomization, cure or improvement was noted in 75 percent of those treated for four weeks and in 85 percent of those treated for six weeks. The estimated relapse rate for the four-week regimen was higher — 27 as compared with 16 percent — whereas the incidence of toxic effects for the two regimens was similar — 44 as compared with 43 percent. Among 23 transplant recipients, 4 of 5 treated for four weeks relapsed, leading to the decision to treat the rest of the group for six weeks. Only 3 of the 18 treated for six weeks relapsed. In a third group of 80 patients, the protocol was not followed during the initial four weeks, and these patients were not randomized. Thirty-eight died or relapsed. Multifactorial analysis of pretreatment factors for all 194 patients identified three significant predictors (P These and other findings in this study are consistent with the view that the four-week regimen should be reserved for patients who have meningitis without neurologic complications, underlying disease, or immunosuppressive therapy; a pretreatment cerebrospinal fluid white-cell count above 20 per cubic millimeter and a serum cryptococcal antigen titer below 1:32; and at four weeks of therapy, a negative cerebrospinal fluid India ink preparation and serum and cerebrospinal fluid cryptococcal-antigen titers below 1:8. Patients who do not meet these criteria should receive at least six weeks of therapy. (N Engl J Med 1987; 317:334–41.

A common variant at the TERT-CLPTM1L locus is associated with estrogen receptor–negative breast cancer

Estrogen receptor (ER)-negative breast cancer shows a higher incidence in women of African ancestry compared to women of European ancestry. In search of common risk alleles for ER-negative breast cancer, we combined genome-wide association study (GWAS) data from women of African ancestry (1,004 ER-negative cases and 2,745 controls) and European ancestry (1,718 ER-negative cases and 3,670 controls), with replication testing conducted in an additional 2,292 ER-negative cases and 16,901 controls of European ancestry. We identified a common risk variant for ER-negative breast cancer at the TERT-CLPTM1L locus on chromosome 5p15 (rs10069690: per-allele odds ratio (OR) = 1.18 per allele, P = 1.0 × 10−10). The variant was also significantly associated with triple-negative (ER-negative, progesterone receptor (PR)-negative and human epidermal growth factor-2 (HER2)-negative) breast cancer (OR = 1.25, P = 1.1 × 10−9), particularly in younger women (<50 years of age) (OR = 1.48, P = 1.9 × 10−9). Our results identify a genetic locus associated with estrogen receptor negative breast cancer subtypes in multiple populations

Testing for Dihydropyrimidine Dehydrogenase Deficiency to Individualize 5-Fluorouracil Therapy

Severe adverse events (toxicity) related to the use of the commonly used chemotherapeutic drug 5-fluorouracil (5-FU) affect one in three patients and are the primary reason cited for premature discontinuation of therapy. Deficiency of the 5-FU catabolic enzyme dihydropyrimidine dehydrogenase (DPD, encoded by DPYD) has been recognized for the past 3 decades as a pharmacogenetic syndrome associated with high risk of 5-FU toxicity. An appreciable fraction of patients with DPD deficiency that receive 5-FU-based chemotherapy die as a result of toxicity. In this manuscript, we review recent progress in identifying actionable markers of DPD deficiency and the current status of integrating those markers into the clinical decision-making process. The limitations of currently available tests, as well as the regulatory status of pre-therapeutic DPYD testing, are also discussed