P5-18-05: Incidence of Febrile Neutropenia in Patients Treated with Docetaxel and Cyclophosphamide (TC) for Adjuvant Breast Cancer

Background: Adjuvant docetaxel with cyclophosphamide (TC) chemotherapy use in the community is common based on its improved disease outcomes compared to doxorubicin with cyclophosphamide (AC) treatment, lack of cardiac toxicity associated with anthracyclines, and perceived low incidence of febrile neutropenia (FN). In the pivotal trial of AC versus TC, the incidence of FN in breast cancer patients who received TC treatment was 4% in patients under 65 years and 8% in patients greater than 65 years. Growth factors (CSF) were not used in the trial, but antibiotics were used significantly. FN rates of 11.6% to 50% have been reported in multiple small studies, prompting warnings that primary prophylaxis with growth factor should be used. The true incidence of FN in community based patients may be higher than in the original clinical trial population as non-trial patients may have risk factors known to increase the risk for chemotherapy-induced FN, including increased age or other comorbid conditions. We wanted to know the incidence of FN in patients receiving TC chemotherapy who were not given primary prophylaxis with CSF.

Methods: Using our electronic medical record system, a retrospective review of patients starting TC for breast cancer in 2010 at Kaiser Permanente Northern California was included. Patients had started a four or six cycle regimen of docetaxel 75 mg/m2 and cyclophosphamide 600 mg/m2 every 21 days. Patients were stratified into two groups: (1) CSF primary prophylaxis given with the first cycle versus (2) no CSF primary prophylaxis given with the first cycle. CSF prophylaxis was given by physician choice. FN episodes were defined with a clinical diagnosis code for FN from emergency department visits or hospitalizations. The primary outcome was the incidence of TC-induced FN in patients who did not receive CSF primary prophylaxis with the first cycle of treatment.

Results: 332 patients with a mean age of 57.9 years (range 30.5 to 83.6 years) were included. Of these, 204 (61.4%) did not receive primary CSF prophylaxis (mean age 57.4 years, range 30.5 to 83.6 years), and 128 (38.6%) received primary CSF prophylaxis (mean age 58.5 years, range 36.6 to 82.4 years). The incidence of FN during any cycle was 24.5% (50/204) in those who did not receive primary CSF prophylaxis and 8.6% (11/128) in those who did (p=0.0003). Patients were hospitalized for FN for a total of 174 days (mean 3.2 days, range 1 to 13 days). Mean days hospitalized were 3.2 in each group. We will present risk factors associated with the development of FN. Conclusion: In the largest population based report to date, we report the incidence of febrile neutropenia to be 24.5% in patients not receiving primary CSF prophylaxis. The rate is higher than originally reported for TC. Primary prophylaxis with CSF should be considered when treating this patient population with TC chemotherapy. Further analysis, including risk factor assessment, will be presented.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-18-05.

Oogenesis defects in a mutant mouse model of oculodentodigital dysplasia

The essential role of connexin43 (Cx43) during oogenesis has been demonstrated by the severe germ cell deficiency and arrested folliculogenesis observed in Cx43 knockout mice. Recently, another mutant mouse strain became available (Gja1(Jrt)/+) that carries the dominant loss-of-function Cx43 mutation, Cx43(G60S). Gja1(Jrt)/+ mice display features of the human disease oculodentodigital dysplasia (ODDD), which is caused by mutations in the GJA1 gene. We used this new mutant strain to study how a disease-linked Cx43 mutant affects oogenesis. We found that female mutant mice are subfertile with significantly reduced mating success and small litters. The phosphorylated species of the Cx43 protein are reduced in the mutant ovaries in association with impaired trafficking and assembly of gap junctions in the membranes of granulosa cells, confirming that the mutant protein acts dominantly on its wild-type counterpart. Correspondingly, although starting with a normal abundance of germ cells, ovaries of the mutant mice contain significantly fewer pre-ovulatory follicles and do not respond to superovulation by gonadotropins, which is at least partially the result of reduced proliferation and increased apoptosis of granulosa cells. We conclude that the Gja1(Jrt) mutation has a dominant negative effect on Cx43 function in the ovary, rendering the females subfertile. Given these findings, closer examination of reproductive function in ODDD human females is warranted.

Rescue of oogenesis in Cx37-null mutant mice by oocyte-specific replacement with Cx43

Mammalian oocytes and surrounding granulosa cells are metabolically coupled via gap junctions. In growing follicles of the mouse, gap junctions between oocytes and granulosa cells are assembled from connexin 37 (Cx37, encoded by Gja4), whereas those between granulosa cells are assembled from connexin 43 (Cx43, encoded by Gja1). This spatial separation, and the different permeability properties of gap junctions composed of Cx37 and Cx43, suggests that Cx37 channels serve a unique function in oogenesis. Female mice lacking Cx37 are sterile because oocytes do not complete their development. To test the hypothesis that the unique properties of Cx37 make it irreplaceable in oocytes, Cx43 was ectopically expressed in growing oocytes lacking Cx37. Transgenic mice were produced in which Gja1 is expressed in oocytes under control of the Zp3 (zona pellucida protein 3) gene promoter. When the transgene was crossed into the Cx37-null mutant line, oocyte-granulosa-cell coupling, oocyte growth and maturation, and fertility were all restored. Thus, despite their different properties, Cx43 is physiologically equivalent to Cx37 in coupling oocytes with granulosa cells.

A multivariate analysis of socio-demographic factors, water contact patterns and Schistosoma mansoni infection in an endemic area in Brazil

Associations between socio-demographic factors, water contact patterns and Schistosoma mansoni infection were investigated in 506 individuals (87% of inhabitants over 1 year of age) in an endemic area in Brazil (Divino), aiming at determining priorities for public health measures to prevent the infection. Those who eliminated S. mansoni eggs (n = 198) were compared to those without eggs in the stools (n = 308). The following explanatory variables were considered: age, sex, color, previous treatment with schistosomicide, place of birth, quality of the houses, water supply for the household, distance from houses to stream, and frequency and reasons for water contact. Factors found to be independently associated with the infection were age (10-19 and > or = 20 yrs old), and water contact for agricultural activities, fishing, and swimming or bathing (Adjusted relative odds = 5.0, 2.4, 3.2, 2.1 and 2.0, respectively). This suggests the need for public health measures to prevent the infection, emphasizing water contact for leisure and agricultural activities in this endemic area.

Validity of selected clinical signs and symptoms in diagnosis of Schistosoma mansoni infection

Sensitivity, specificity and positive predictive values of selected clinical signs and symptoms in the diagnosis of Schistosoma mansoni infection were evaluated in 403 individuals (69% of inhabitants over 1 year of age) in an endemic area in Brazil (Divino). Highest sensitivity (13%) was found for blood in stools. Specificity over 90% was found for blood in stools, palpable liver with normal consistency and palpable hardened liver at middle clavicular (MCL) or middle sternal lines (MSL). Hardened liver at MSL (83%) or MCL (75%), and blood in stools (78%) presented higher positive predictive values for S. mansoni infection, while palpable liver with normal consistency at MCL (45%) or MSL (48%) presented smaller values. Enlarged liver without specification of its consistency has been traditionally used as an indicator of the infection in areas where malaria or Kala-azar are not endemic. Our results demonstrate that the probability that a person with blood in stools or hardened palpable liver is infected is higher than among those with palpable liver with normal consistency.