Chemoprevention Trial of Contralateral Breast Cancer with Fenretinide. Rationale, Design, Methodology, Organization, Data Management, Statistics and Accrual

The Fenretinide (4-HPR) Breast Cancer Study is a randomized multicenter clinical trial originally designed and conducted by the investigators of the Istituto Nazionale Tumori of Milan. The study is sponsored by the National Cancer Institute of Bethesda and by the Italian National Research Council. The trial was designed to evaluate the effectiveness of the synthetic retinoid 4-HPR, at a dose of 200 mg per os every day for 5 years, in reducing the incidence of contralateral breast cancer in a population of patients previously operated on for breast cancer. Between 1987 and 1993, the Istituto Nazionale Tumori of Milan and 9 other collaborating Centers enrolled 2,972 women between the ages of 30 and 70 years who had been previously operated on for T1-T2 N- M0 breast cancer. This paper describes the rationale, design, methodology, organization, data management, statistics and accrual of the participating population.

Phase II Study with Lonidamine in the Treatment of Hormone-Refractory Prostatic Cancer Patients

Twenty-one patients with metastatic prostate cancer who had become refractory to hormonal therapies received lonidamine (150 mg tid and 600 mg daily dose in 17 and 4 patients, respectively). In all but 4 patients, treatment was continued until disease progression or the development of severe toxicity. Toxicity was minimal and reversible (score 1 or 2) and included myalgia (8 cases), arthralgia (6 cases), gastrointestinal toxicity (11 cases), fatigue (14 cases) and testicular pain (9 cases). The response was evaluated after at least one month of therapy with lonidamine, according to NPCP-USA recommendations. Of 21 patients who entered the study, only 15 were evaluable for response; 2 died (1 for severe toxicity and 1 for drug-unrelated reasons). No objective response was obtained in the series. In fact, only 6 patients achieved stable disease and 9 progressed. Median survival time from the beginning of treatment was no longer than that of patients in a similar condition who were treated with standard palliative maneuvers. We conclude that this therapeutic approach with lonidamine is not active in hormone-refractory prostatic cancer patients with distant metastasis.

Abstract S5-08: Breast cancer incidence after hormonal infertility treatments: Systematic review and meta-analysis of population based studies

Background: With the increasing practice of hormonal infertility treatments in infertile women, both for ovulation induction in anovulatory women and for ovarian hyperstimulation in assisted reproductive technologies, concerns have been raised about the long-term effects of such practice on the subsequent risk of breast cancer. Sterility itself is an independent risk factor, though its effect is not yet clear. In the past years, a number of population-based studies has addressed the possible association between breast cancer incidence and infertility treatments, with inconsistent results. With these premises, we performed a systematic review and pooled analysis of the association between infertility treatments by any kind of hormonal manipulation and breast cancer incidence, based on published data.

Methods: Population cohort studies, evaluating the association between BC incidence and hormonal infertility treatments were identified by literature search. Standardised Incidence Ratios (SIRs) were pooled across the studies by inverse variance weighting. Subgroup analyses were performed according to the following covariates: length of follow up (< 10 yrs vs > 10 yrs), type of hormonal therapy (clomiphene vs gonadotropins) and type of control group (population based on internal control, ie infertile women). All statistical tests were two-sided.

Results: Seventeen eligible studies were identified and retrieved. Data on breast cancer incidence and type of fertility treatments were available for all studies. Overall hormonal infertility treatments were associated with a 11% increase in BC incidence as compared with untreated women (SIR SIR 1.11, 95%CI 0,91-1,30). BC risk was slightly higher in clomiphene treated women (SIR 1.04; 95%CI 0.76-1.32) than in gonadotropins users (SIR 0.83; 95%CI 0.60-1.07), p for interaction < 0.0001. The increase in BC incidence seems to be dependent on follow up duration (SIR 0.94; 95%CI 0.8-1.08 for <10 yrs vs 1.23; 95%CI 0.86-1.6 for > 10yrs, p for interaction < 0.0001). In the subset of cohort studies using population based estimates as controls, hormonal infertility treatment was associated with an increase in breast cancer risk (SIR 1.13, 95% CI 0.86-1.41); in studies with internal controls, i.e. cohorts of untreated infertile women, a similar breast cancer risk was observed (SIR 1.00; 95%CI 0.73-1.26; p for interaction <0.001).

Conclusions: Overall hormonal infertility treatments do not appear to be consistently associated with a significant increase in breast cancer incidence. Subset analyses suggest a possible increase in BC incidence with longer FU (>10 yrs) whereas the use of gonadotropins might exert a protective effect.

Finally, subset analyses according to type of controls suggest that the observed increased risk reported by several studies may be attributable to the infertility condition itself.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr S5-08.

N-(4-hydroxyphenyl)retinamide promotes apoptosis of resting and proliferating B-cell chronic lymphocytic leukemia cells and potentiates fludarabine and ABT-737 cytotoxicity

The in vitro effects of the synthetic retinoid N-(4-hydroxyphenyl)retinamide (4HPR, fenretinide) on primary B-cell chronic lymphocytic leukemia (CLL) cells from previously untreated CLL patients were investigated. 4HPR promoted the intrinsic apoptotic pathway by reactive oxygen species (ROS) generation and was accompanied by drop of Mcl-1 protein expression. The latter was not attributable to transcriptional downregulation but to protein degradation mediated by jun N-terminal kinase activation, and likely by NF-kB downregulation and Noxa upregulation. CLL cells stimulated in vitro with CD40L did not increase 4HPR chemoresistance if activation was accompanied by proliferation. Intra-patient analysis confirmed that the proliferating pool of CLL cells was more sensitive to the cytotoxic action of 4HPR than the activated but resting CLL subpopulation. The different 4HPR susceptibility of the two subpopulations was associated with higher Noxa expression in proliferating CLLs. Combination experiments revealed that 4HPR strongly potentiated ABT-737 cytotoxicity, especially in proliferating CLL cells that displayed amplified chemoresistance to ABT-737 alone. Synergic cytotoxicity was also demonstrated in combination with fludarabine, in both resting and stimulated CLL samples. This study entitles 4HPR to be assayed as a chemotherapeutic adjuvant for the treatment of CLL.

Identification of a Prognostic Signature Based on the Expression of Insulin-Related Genes in Early Breast Cancer

Background: A substantial body of evidence indicate that the insulin pathway plays a key role in breast cancer development and progression and may represent a therapeutic target, especially in those patients exposed to high plasmatic level of insulin. However, the potential prognostic role of genes related to the insulin-pathway in breast cancer cells has not been explored. With these premises, we evaluated the prognostic role of the expression of genes related to the insulin pathway in early breast cancer. Methods: Candidate genes were selected from published literature, genomic databases, and gene expression profiling experiments performed in insulin resistant subjects, yielding 143 genes that were used to develop a molecular classifier. We used three publicly available breast cancer datasets, GSE1456, GSE3494 and GSE2990 that include gene expression data on a total of 502 cases with clinical follow up. The insulin gene signature was developed on GSE1456, containing microarray data from 159 early breast cancer patients. This dataset was split by a random procedure into a training set and a validation set. Univariate non-parametric Mann-Whitney U test was used to identify genes differentially expressed. Expression of genes significantly correlated with relapse was combined in a linear score. Patients were classified as low or high risk with respect to the median score. External validation was performed on GSE3494 and GSE2990. Results: On the training set, 15 genes resulted differentially expressed in relapsed and non relapsed patients: the 8-year disease free survival (DFS) was 91% (SE =4%) and 51% (SE = 8%) in the high and low risk group (p< 0.001); HR = 10.6 (95% CI 3.2-35.5, p<0.00001). In the validation set, the 8-year RFS was 97% (SE = 3%) and 54% (SE = 10%), respectively (p = 0.009); HR = 4.6 (95% CI 1.01 to 20.7, p 0.04). External validation was performed on two independent datasets, GSE3494 and GSE 2990 including 350 early breast cancer patients. In GSE3494 the 8-year DFS was 72% (SE = 5%) and 61% (SE = 4%) in the high and low risk group (p = 0.03), respectively. In GSE 2990 the 8-year DFS was 74% (SE = 7%) and 55% (SE = 8%), respectively, (p = 0.03). By multivariate analysis, the insulin signature resulted significantly associated with DFS, independently of age, tumor size, ER status, nodal status and grade. Conclusions: Our findings indicate that the insulin pathway is involved in breast cancer prognosis at a genomic level and might provide a better way to individualize therapeutic interventions targeting insulin signaling.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 108.

Low-Dose Tamoxifen for the Treatment of Breast Ductal Intraepithelial Neoplasia: Results of a Large Observational Study

Background: The cost-benefit ratio of tamoxifen for breast ductal intraepithelial neoplasia (DIN) is unclear. Since low-dose tamoxifen showed a favorable safety profile and modulation of breast cancer biomarkers in phase II trials, we analyzed a large mono-institutional cohort of women with DIN treated with low-dose tamoxifen or no systemic treatment.Material and Methods: A total of 309 patients with ER positive DIN received either tamoxifen 5 mg/day or 20 mg/week, as part of clinical trials or institutional guidelines and were compared with 371 patients who received no systemic treatment after surgery with or without radiotherapy due to personal preference, allocation to placebo or contraindication to tamoxifen.Results: The 5-year cumulative incidence of recurrence was 14.5% (95% CI, 11.9-17.5), with a negative trend according to age. Women with ER/PgR >50% DIN who were untreated had a higher incidence of breast events than women on tamoxifen (HR 1.76; 95% CI, 1.00-3.12) or women with ER/PgR<50% DIN (HR 1.72; 95% CI, 1.14-2.58). Among untreated patients with ER>50% DIN, recurrence was higher in PgR ≥50% DIN than in PgR <50% DIN, whereas it was similar among low PgR (<50%) DIN against which tamoxifen had no effect. No difference in endometrial cancer incidence was noted.Discussion: High ER and especially high PgR expression is a significant adverse prognostic indicator of DIN against which low-dose tamoxifen appears to be a safe and active treatment. Conversely, women with low expression ER or PgR DIN do not seem to benefit from tamoxifen. A definitive clinical trial is warranted.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2113.

Randomized phase II trial of budesonide versus placebo in high-risk population with screening-detected lung nodules: Update on secondary endpoints

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Background: Lung cancer phase II chemoprevention trials have not focused so far on the peripheral lung. CT discovers small, undetermined peripheral nodules, which may be preinvasive lesions. In a recent phase II trial the glucocorticoid Budesonide reduced peripheral nodules at spiral CT. Methods: We performed a randomized, double-blind, placebo-controlled, phase IIb clinical trial of inhaled budesonide in current (CS) or former smokers (FS) with CT-detected peripheral nodules. Primary endpoint: shrinkage effect on nodules. Secondary endpoints: decrease in size/number of the target lesions, modulation of tumor markers in sputum and plasma, toxicity, effect on pulmonary function. Two hundred and two subjects received 800μg budesonide (B) twice daily or placebo (P) for 1 year. CT scans at 0 and 12 months (mts), and clinical evaluation + serum/plasma collection at 0, 3, 6, and 12 months were performed. Subjects were stratified according to gender, smoking habits (CS vs. FS), and nodule characteristics (solid vs. non-solid). Results: Preliminary data had shown no shrinkage of the nodules in the B treated arm in a per subject analysis (primary objective). We present now results on serum markers (ultrasensitive C-reactive protein, CRP), emphysema and pulmonary function. As compared to baseline, CRP median levels show at 12 months a nonsignificant (p = 0.85) reduction: -0.25 ± 0.63 (B) vs. -1.16 ± 0.97 (P). 12-month values are significantly (p = 0.01) associated with baseline values and smoking status, with higher mean values at 12 months in FS (B 2.1 ± 2.0 vs. P 3.4 ± 1.9). Emphysema values at 12 months are significantly higher (p = 0.0022) in the B (+ 0.29 ± 0.06) versus P arm (+ 0.12 ± 0.07). This difference is not correlated to sex (p = 0.7062) and smoking status (p = 0.8044). As regards spirometry, no significant difference on FEV 1% and DLC/VA appears between arms at 12 months: median FEV 1% values 3.7 ± 1.0 for B versus 2.9 ± 1.0 for P (p = 0.6221); median DLC/VA increase of 0.3 ± 1.9 (B) versus decrease of -3.8 ± 1.6 (P) (p = 0.4191). Conclusions: A significant effect of B on ultrasensitive-CRP and pulmonary function has not been shown. CRP results may indicate the lack of systemic absorption of B. Emphysema appears slightly worse in the B arm, particularly in FS; this is worth further investigation.

No significant financial relationships to disclose.

The effect of transdermal estradiol or oral conjugated oestrogen and fenretinide versus placebo on haemostasis and cardiovascular risk biomarkers in a randomised breast cancer chemoprevention trial

Background:

We have previously reported the favourable effect of transdermal estradiol (E2), relative to oral conjugated equine oestrogen (CEE), on ultrasensitive C-reactive protein after 12 months of treatment in a retinoid-placebo controlled two-by-two randomized breast cancer prevention trial (Decensi A et al (2002) Circulation106 10 1224–8). Here, we investigate the changes in lipids and clotting profile in patients of the same trial.

Methods and results:

Recent post-menopausal women were randomised to either oral CEE 0.625 mg/day and placebo (n = 55), CEE and fenretinide 200 mg/day (n = 56), transdermal E2 50 mg/day and placebo (n = 59) or E2 and fenretinide 200 mg/day (n = 56). Sequential medroxyprogesterone acetate 10 mg/day was given in each group. After 12 months, there was a statistically significant effect of the route of administration of hormone replacement therapy (HRT) on fibrinogen levels; the median percentage change being −5.7% with CEE and −1.1% with E2 (p = 0.012). Total cholesterol decreased in all arms (p < 0.0001). HDL-C decreased significantly with transdermal E2 (p = 0.006) compared to oral CEE and with fenretinide relative to placebo (p<0.001). Triglycerides exhibited an opposite modulation in the HRT route, with a 21.4% median increase with oral CEE and an 8.6% reduction with transdermal E2 (p < 0.0001). Antithrombin-III showed a 4% borderline significant reduction in the fenretinide arm relative to placebo, irrespective of the HRT administration route (p = 0.055).

Conclusions:

Our data indicate that transdermal E2 may be preferable to oral CEE based on its safer cardiovascular risk profile. Fenretinide modified some cardiovascular risk biomarkers and confirmed a safer profile compared to other retinoids.

Correlation of low dose tamoxifen and its metabolites plasma level with Cyp 2D6, and SULT polymorphism; a pharmacogenetics study within a chemoprevention trial

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Background: Tamoxifen (T) is one of the most widely used drug for the treatment and prevention of estrogen receptor (ER) positive breast cancer. Individual genotype can modulate treatment efficacy. T metabolism is catalyzed by multiple enzymes: CYP2D6 is the main mediator for endoxifen, one of the most potent T metabolites. SULT may also play a role in T activation and can modulate hormone levels involved in breast cancer risk. Within a chemoprevention trial, we correlated T and its main metabolite concentration with polymorphisms (SNPs) of CYP2D6 and SULT genes. Methods: Premenopausal women (n 235) were randomly assigned in a double-blind four-arm trial to receive T 5 mg/d, fenretinide 200 mg/d, both agents, or placebo for 2 years CYP2D6 (*4–6) and SULT1A1*3 frequencies were determined using an Allelic Discrimination Assay, following a protocol for real time polymerase chain reaction. In the subjects receiving T, we measured plasma level of the drug, and its metabolites (endoxifen, 4-hydroxy-T, N-desmethyl-T, N-desdimethyl-T and Tnoxide) using a fluorescence detector at 12 and 24 months. Results: SNPs analysis was performed in 118 women; we found 65% wild type (WT), 31% heterozygous (H) and 5% mutated (M) for CYP2D6. The SNP frequency of SULT1A was A1, 61%; SULT1A2 36% and SULT1A3 3%. At one year a positive correlation was observed between CYP2D6 M and plasma level of N- desmethyl-T, the mean plasma level being 54.6, 62.4 and 108.5 ng/ml in WT, H and M, respectively, p=.001 (p=.01 at 24 months). Endoxifen was slightly increased in the WT compared to M (15.4 vs 12.9 ng/ml). SULT polymorphisms did not show any correlation with the drug and metabolite levels. Conclusions: CYP2D6 M mediates an increased level of N- desmethylT. This observation supports the role of CYP2D6 as an important enzyme in T metabolism, but more than one cytochrome P450 isoenzymes is required. to identify good or poor T metabolizers.

No significant financial relationships to disclose.

Phase I-II trial of weekly bicalutamide in men with high PSA and negative biopsy

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Background: Men with persistent PSA elevation after non-cancer findings are at high risk of prostate cancer (PC). Bicalutamide (Bic) is an androgen receptor antagonist, which, unlike finasteride, is not associated with testosterone (T) escape. Given its long half-life (6–8 days), allowing for a weekly administration with potentially reduced side effects, Bic may be a suitable chemopreventive agent. We assessed the activity and safety of a weekly low-dose Bic in a phase I-II study in subjects with PSA >4 ng/ml and no PC at initial biopsies (10- 12 cores). Methods: Eligible subjects were sequentially assigned to either Bic 50 mg/week (group A), or 100 mg/week (group B), or no treatment (group C) for 6 mos. The outcome measures were the 6 mos changes in tissue Ki67 (primary endpoint), topoisomerase-IIa, Bcl- 2, and COX-2 by IHC, morphology and circulating PSA, prostatic acid phosphatase (PAP) and hormones. Results: From May, 2004 to June, 2006, 107 subjects were screened and 80 were enrolled: 26 in group A, 28 in group B, and 26 in group C. High-grade (HG) PIN decreased from 32% to 23% in the treated group and increased from 24% to 34% in controls; proliferative inflammatory atrophia (PIA) decreased from 41% to 32% in the treated group and increased from 14% to 19% in the controls. Complete remission of HG-PIN was found in 10/14 treated subjects versus 1/5 controls. Cancer or HG-PIN were found in 11 control subjects (52%) versus 16 subjects (36%) in the treated arms at 6 mos. Ki67 expression was significantly higher in HG-PIN lesions than in normal tissue (12% vs. 3%, p<0.01), but it was not modulated by Bic. Bcl-2 expression in normal tissue was 0/1+ in most subjects, and increased in 36% of treated subjects versus 20% of controls. Total and free PSA, as well as PAP, decreased by >30% on Bic. T, LH, estradiol and SHBG increased on Bic by 50–60%. There was no dose-related modulation in any biomarker. Treatment was well tolerated, mild (G1) breast pain and gynecomastia being recorded in 40% of treated subjects. Conclusions: Weekly Bic is active and safe in subjects with high PSA and negative biopsy. It seems to be associated with HG- PIN remission, Bcl-2 overexpression and a favorable modulation of PSA. The dose of 50 mg/week should be selected for future chemoprevention trials.

No significant financial relationships to disclose.

The hormone replacement therapy opposed to low dose tamoxifen (HOT) study: safety data from an ongoing phase III trial

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Background: Primary prevention trials have shown that tamoxifen (T) lowers ER+ breast cancer (BC) incidence by 48%. While the IBIS I update showed mixed findings, the Italian trial showed an interesting positive risk/benefit ratio in T and hormone replacement therapy (HRT) users: fewer BC, endometrial cancer comparable to placebo, and no cardiovascular diseases (CVD) excess. In a phase II study, low dose T and HRT showed a safe gynecological profile and did not increase menopausal symptoms. Moreover low dose T maintains the same antiproliferative effects as the standard dose. To improve BC prevention and quality of life (QoL) in menopausal women we started a multicentric, phase III trial of low dose T in HRT users. Methods: current or de novo HRT users are randomized to T 5 mg/day or placebo for 5 yrs. The primary aim is the reduction of invasive or in situ BC. Secondary aims are: safety, gene polymorphisms (SNPs) correlated to BC risk and T activity. In a subgroup transvaginal ultrasound (TvUS) and endometrial biopsy is being performed after 3 years of treatment to monitor endometrial effects. Results: as of December 31 2006, 1870 women were enrolled, of which 21% were hysterectomized. Median age is 53 years (33–72), BMI is <25 in 66%, =25<30 in 26%, >30 in 8%. Current or de novo users are 80% and 20%. 84% participants have at least one follow-up visit. 128 subjects performed already the 3 years TvUS and endometrial biopsy: so far no atypical hyperplasia or cancer was found. A modest increase of menopausal symptoms was observed (hot flashes 42% vs 52%, night sweating 39% vs 44%). Drop-outs are 23%, of which 13% due to AE including: 21 cancers (12 invasive BC, 1 DCIS), 13 CVD (3 VTE), 9 gynecological (5 endometrial polyps). Conclusions: combination of low dose T and HRT has reasonable safety profile, we have reached almost 1,900 women on study and AE rate is very low. These unblinded findings support the safety of the association of HRT and T.

No significant financial relationships to disclose.

Fifteen-year results of a randomized phase III trial of fenretinide to prevent second breast cancer

PURPOSE

The synthetic retinoid fenretinide administered for 5 years for prevention of second breast cancer showed no difference after a median of 8 years, but a possible reduction in premenopausal women. We conducted a long-term analysis in a subgroup of women who were regularly followed up in a single center.

PATIENTS AND METHODS

We analyzed data after a median follow-up of 14.6 years (IQ range, 12.3-16.3 years) from 1739 women aged 30-70 (872 in the fenretinide arm and 867 in the observation arm), representing 60% of the initial cohort of 2867 women. The main efficacy endpoint was second primary breast cancer (contralateral or ipsilateral).

RESULTS

The number of second breast cancers was 168 in the fenretinide arm and 190 in the control arm (hazard ratio = 0.83, 95% CI, 0.67-1.03). There were 83 events in the fenretinide arm and 126 in the observation arm in premenopausal women (HR = 0.62, 95% CI, 0.46-0.83), and 85 and 64 events in postmenopausal women (HR = 1.23, 95% CI, 0.63-2.40). The younger were the women, the greater was the risk reduction associated with fenretinide, which attained 50% in women aged 40 years or younger and disappeared after age 55 (P-age*treatment interaction = 0.023). There was no difference in cancers in other organs, distant metastases or survival.

CONCLUSIONS

Fenretinide induces a significant risk reduction of second breast cancer in premenopausal women, which is remarkable at younger ages, and persists several years after treatment cessation. Since adverse events are limited, a trial in young women at high-risk is warranted.

Initial results of a phase III study show safety of HRT and low dose tamoxifen

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Background: HRT is beneficial on menopausal disturbancies and decreased bone fracture risk and colorectal cancer (CRC), but increased VTE, cardiovascular events and breast cancer in the WHI trial. However, the WHI characteristics (median age 63.3 yrs, median BMI 28.5, use of oral HRT) diminish generalization of results. The WHI trial shows an increased BC risk, only with oral combined HRT. HRT and tamoxifen (T) was safe in subgroups of two prevention trials. T at low doses showed antiproliferative effects similar to the standard dose, without significant menopausal symptoms and endometrial proliferation. Methods: The HRT+T combination is being investigated in a multicentric, phase III trial in current or de novo HRT users, randomized to either T 5 mg/day or placebo for 5 yrs. The primary endpoint is the reduction of invasive and in situ BC. Results: Of 5,032 women contacted, 1,989 refused, 1,109 were not eligible, and 1,806 were enrolled in 46 centres. Median age is 53 years (33–72). BMI is <20 in 65.7%, <25 in 26.3%, >25 in 8.0%. Current or de novo users are 80.1% and 19.9%. In the former group, 45.9% use oral and 54.1% use TTS. Hysterectomized women are 389. Current users ≤3 years are 48.0%, 3–5 years 12.1%, >5 years 18.8%. 1256 women (74.2%) have at least one follow-up visit. Compared to baseline, most frequent side effects were: hot flashes (42.0% vs 35.0%), night sweating (39.0% vs 29.0%), anxiety/depression (41.0% vs 27.4%), vaginal dryness (29.2% vs 19.3%), headache (32.1% vs 25.1%), fluid retention (24.0% vs 19.0%). “Drop-outs” are 17.3%, of which 11.2% due to adverse events (AE). The 35 AE include: 12 cancers (incl. 7 invasive BC’s, 1 DCIS, 1 CRC), 11 cardiovascular (incl. 1 stroke, 1 AMI, 2 VTE, 1 angina, 2 TIA), 2 gynecologic (uterine polyps). Conclusions: In spite of the current negative scenario for HRT, we have reached over 1,800 women on study. Compliance is acceptable and treatment appears safe. The rate of AE is far lower than the WHI trial, possibly as a result of the different population characteristics. These preliminary findings justify the carry-on of the study in order to reach enough power for the main endpoint and perform secondary evaluations.

No significant financial relationships to disclose.

Clinical trials with retinoids for breast cancer chemoprevention

Retinoids have been studied as chemopreventive agents in clinical trials due to their established role in regulating cell growth, differentiation and apoptosis in preclinical models. Experimental evidence suggests that retinoids affect gene expression both directly, by activating and/or repressing specific genes, and indirectly, by interfering with different signal transduction pathways. Induction of apoptosis is a unique feature of fenretinide, the most widely studied retinoid in clinical trials on breast cancer chemoprevention due to its selective accumulation in breast tissue and to its favourable toxicological profile. In a phase III breast cancer prevention trial, fenretinide showed a durable trend to a reduction of second breast malignancies in premenopausal women. This pattern was associated with a favourable modulation of circulating IGF-I and its main binding protein (IGF-binding protein-3, IGFBP-3), which have been associated with breast cancer risk in premenopausal women in different prospective studies. In a subsequent biomarker study on premenopausal women who had participated in the phase III trial, high IGF-I and low IGFBP-3 baseline levels were found to predict second breast cancer risk, although the magnitude of their changes during treatment did not fulfil the requirements for suitable surrogate end-point biomarkers. In postmenopausal women, fenretinide did not reduce second breast cancer incidence, nor did it induce significant modulation of the IGF system. Similarly, fenretinide was not found to affect risk biomarkers significantly in early postmenopausal women on hormone replacement therapy, who are at increased risk of developing breast cancer. Biomarker studies of fenretinide alone or in combination with different nuclear receptor ligands are being conducted. In particular, clinical trials of fenretinide and tamoxifen have proved to be feasible, and this combination appears to be safe and well tolerated in high-risk women, especially when low-dose tamoxifen is employed. Novel retinoid X receptor-selective retinoids, or rexinoids, have been shown to suppress the development of breast cancer in several animal models with minimal toxicity, and are being intensively studied either alone or in combination with selective oestrogen receptor modulators, both in vitro and in vivo. The rexinoid, bexarotene, has recently been approved for the treatment of patients with cutaneous T-cell lymphoma, and a biomarker trial with bexarotene in women with high breast cancer risk is currently underway.

Chemoprevention of colorectal cancer: an update

Colorectal cancer (CRC) is the leading cause of cancer-related mortality in western countries. Adjuvant treatment does not seem to be highly effective and recurrent or metastatic disease occurs in half of the new cases within one year of diagnosis and median survival does not exceed 18 months. CRC represents an optimal model for primary and secondary prevention, given the availability of effective screening procedures and of a well defined multi-step carcinogenic pathway. Colon cancer is supposed to arise as the result of a series of genetic mutations, which parallel histopathologic and molecular changes, from normal colonic epithelium to invasive carcinoma, with adenomatous polyps as an intermediate step. A growing body of evidence has shown a wide variety of effective compounds, in vitro in animal models and in human clinical trials. The more studied agents are the non-steroidal anti-inflammatory drugs. Among those, aspirin has been shown, in two recent randomised trials, to lower the incidence on polyps vs. placebo. Intervention studies on diet showed disappointing results, but diet micronutrients are promising agents in CRC prevention. Calcium, vitamin D and folic acid in different proportions in different populations have been shown to have a certain degree of action in preventing cancer development in epidemiological studies and in randomised trials. Also oestrogens or, rather, hormone replacement therapy for the menopause can protect against CRC. In conclusion, the rapid growth of information and knowledge in chemoprevention, especially for CRC, is very encouraging and gives us hope that soon this approach will be applicable in a larger scale population.

Effect of tamoxifen at low doses on ultrasensitive C-reactive protein in healthy women

The use of tamoxifen as a breast cancer preventive agent may be contraindicated by an increased risk of endometrial cancer and venous thromboembolic events, particularly in postmenopausal women. Since these estrogenic effects may be dose-related, a dose reduction may reduce toxicity. We have recently shown a comparable activity of lower doses of tamoxifen on putative surrogate biomarkers of cardiovascular disease and breast cancer. To provide further insight into the effect of tamoxifen at low doses on the cardiovascular system, we compared the effect of three different doses on circulating levels of C-reactive protein (CRP), an independent risk marker for cardiovascular disease (CVD), which was lowered by tamoxifen at the standard dose of 20 mg day-1 in previous studies. We compared the changes in CRP after 2 months of either placebo (n = 24), or tamoxifen 10 mg alternate daily (n = 26), or 10 mg day-1 (n = 22), or 20 mg day-1 (n = 19) in healthy women aged 35-70 years. The median percent change was -2.2% (95% CI, -23.3 to 42.8) with placebo, -39.1 (95% CI, -59.9 to -28.7) with 10 mg alternate daily, -56.9% (95% CI, -68.6 to -38.4) with 10 mg day-1 and -42.9% (95% CI, -62.6 to 1.6) with 20 mg day-1 (P = 0.291 for the linear dose-response trend). Similar results were obtained when the data were classified according to blood tamoxifen concentrations, with a median reduction of 47% (95% CI, 65.5-36.3) for women with low tamoxifen concentrations (< 30 ng mL-1). We conclude that tamoxifen at low doses is able to lower ultrasensitive CRP and that this might be associated with a beneficial effect on CVD.

Chemoprevention of breast cancer with fenretinide

Chemoprevention of cancer represents a challenge for oncology during this new millennium. Substantial advances have been accomplished in the last decade, especially for primary and secondary prevention of breast cancer. In addition to tamoxifen, raloxifene and other selective estrogen receptor modulators, retinoids are among the most promising agents, given their ability to inhibit mammary carcinogenesis in preclinical models. Fenretinide, the synthetic amide of retinoic acid, inhibits cell growth mostly through the induction of apoptosis with mechanisms which may partly involve the retinoid receptors. Because it has a favourable toxicological profile, fenretinide has been extensively investigated in clinical trials. A large randomised phase III trial for secondary breast cancer prevention has been recently carried out in Italy. Results showed a reduction of second breast malignancies in premenopausal women. In addition, a significant decrease of circulating insulin-like growth factor (IGF)-1, a known risk factor for premenopausal breast cancer, was observed after 1 year of fenretinide administration in premenopausal women with breast cancer. Ongoing studies on the validation of the circulating IGF-1 as a surrogate endpoint biomarker of fenretinide activity and on the effectiveness of the combination with low dose tamoxifen may provide further insight into the future clinical application of fenretinide.

The Italian breast cancer prevention trial with tamoxifen: findings and new perspectives

The Italian Tamoxifen Prevention Study includes 5408 healthy hysterectomized women aged 35-70 years who have been randomized to 20 mg/day of tamoxifen or placebo for 5 years. After 46 months median follow-up, an increased risk of venous vascular events (38 women on tamoxifen vs. 18 women on placebo, P = 0.0053), mainly consisting of superficial phlebitis, has been observed and 41 breast cancers have occurred (19 on tamoxifen vs. 22 on placebo, P = 0.64). However, subgroup analyses indicated a borderline significant reduction of breast cancer among women continuously on estrogen replacement therapy (ERT, mostly transdermal) and receiving tamoxifen, with 8 cases of breast cancer among 390 ERT users on placebo versus 1 case among 362 ERT users on tamoxifen (RR = 0.13, 95% CI = 0.02-1.02). Withdrawal rate (mainly due to menopausal symptoms) differed according to ERT use, with compliance being 78% and 75% at 3 and 5 years, respectively, for women who never took ERT, and 92% and 88% at 3 and 5 years, respectively, for women not on ERT at baseline, but who took ERT at some time during the trial. Pharmacokinetic and pharmacodynamic (surrogate end point biomarkers) studies showed that a lower dose of tamoxifen (such as 5 mg/day) does not affect the drug's activity on several biomarkers of both cardiovascular and breast cancer risk. We are therefore planning a multicenter placebo-controlled phase III trial in postmenopausal healthy women on hormone replacement therapy (HRT) to test whether the combination of HRT and low-dose tamoxifen retains the benefits while reducing the risks of either agent maintaining a high compliance rate.

Effect of raloxifene on IGF-I and IGFBP-3 in postmenopausal women with breast cancer

The effect on the IGF system of 60 mg and 600 mg daily of raloxifene administered for 2 weeks prior to surgery was investigated in 37 postmenopausal women with breast cancer. Raloxifene significantly decreased insulin-like growth factor (IGF-I) as compared to placebo (P < 0.05) with no dose-response relationship. No significant change was observed in IGFBP-3, while the IGF-I/IGFBP-3 molar ratio was decreased by treatment, with a statistically significant effect only for the higher dose. Given that high plasma levels of IGF-I have been suggested as a risk factor for breast cancer, these findings provide further support for the potential activity of raloxifene in breast cancer prevention.

Long-term effects of fenretinide, a retinoic acid derivative, on the insulin-like growth factor system in women with early breast cancer

High insulin-like growth factor-I (IGF-I) levels are associated with an increased risk of breast cancer in premenopausal women. Because the synthetic retinoid fenretinide showed a beneficial effect on second breast cancers in premenopausal women in a Phase III trial, we studied its long-term effects on IGF-I levels. We measured, at yearly intervals for up to 5 years, the circulating levels of IGF-I, IGF binding protein (BP)-3, and their molar ratio in 60 subjects < or = 50 years of age and 60 subjects > 50 years of age allocated either to fenretinide or no treatment. In women < or = 50 years of age, measurements of IGF-II, IGFBP-1, and IGFBP-2 were also performed. The associations between biomarkers and drug or metabolite plasma concentrations were also investigated. All biomarkers were relatively stable over 5 years in the control group. Compared with controls and after adjustment for baseline, treatment with fenretinide for 1 year induced the following changes: IGF-I, -13% [95% confidence interval (CI), -25 to 1%] in women < or = 50 years of age and -3% (95% CI, -16 to 13%) in women > 50 years of age; IGFBP-3, -4% (95% CI, -12 to 6%) in both age groups; IGF-I:IGFBP-3 molar ratio, -11% (95% CI, -22 to 1%) in women < or = 50 years of age and 1% (95% CI, -11 to 16%) in women > 50 years of age. These effects were apparently maintained for up to 5 years, although fewer samples were available as time progressed. No change in other IGF components was observed. Drug and metabolite concentrations were negatively correlated with IGF-I and IGF-I:IGFBP-3 molar ratio in women < or = 50 years of age. Fenretinide induces a moderate decline of IGF-I levels in women < or = 50 years of age. The association between IGF-I change and the reduction of second breast cancers in premenopausal women warrants further study.

Effect of raloxifene on breast cancer cell Ki67 and apoptosis: a double-blind, placebo-controlled, randomized clinical trial in postmenopausal patients

PURPOSE

Raloxifene is a selective estrogen receptor (ER) modulator approved for prevention and treatment of postmenopausal osteoporosis. This is an exploratory study of raloxifene in primary breast cancer patients.

EXPERIMENTAL DESIGN

Postmenopausal women (50-80 years of age), with histological or cytological diagnosis of stage I or II primary breast cancer, were randomly assigned to 14 days of placebo, 60 mg/day raloxifene, or 300 mg twice daily (600 mg/day) of raloxifene. A core biopsy of the primary tumor was obtained before therapy, and a representative sample of the excised tumor was obtained from the operative specimen after treatment. Paired baseline and endpoint biopsies from each patient were analyzed for Ki67, apoptosis, and estrogen and progesterone receptors. Treatment group differences in efficacy measurements were primarily evaluated for baseline-to-endpoint change and percentage change using a one-way ANOVA with treatment as the fixed effect.

RESULTS

Of 167 enrolled patients, 143 had evaluable efficacy data. Most breast cancer cases were invasive (98.6%), stage I (76.6%), and ER-positive (83.2%). In patients with ER-positive tumors, Ki67 increased 7% from baseline on placebo and decreased by 21% on 60 mg/day raloxifene (P = 0.015 versus placebo) and by 14% on 600 mg/day raloxifene (P = 0.064 versus placebo). Raloxifene did not affect apoptosis. ER decreased significantly with 60 mg/day or 600 mg/day raloxifene compared with placebo (P < 0.01 for each comparison). Raloxifene had no statistically significant effects on Ki67 among patients with ER-negative tumors. There were no treatment differences in adverse events.

CONCLUSION

In this exploratory trial, 60 mg/day raloxifene showed a significant antiproliferative effect in ER-positive breast cancer, demonstrated by the decrease in Ki67, with no effect in ER-negative cancer. This provides support for raloxifene having a breast cancer preventive effect in postmenopausal women.

Effect of low dose tamoxifen on the insulin-like growth factor system in healthy women

The use of tamoxifen as a preventive agent may be limited by the increased risk of endometrial cancer and venous thromboembolic events observed in postmenopausal women. We have recently shown a comparable activity of lower doses of tamoxifen on several surrogate biomarkers of cardiovascular disease and breast cancer, including Insulin-like Growth Factor-I (IGF-I). To provide further insight into the effect of tamoxifen at low doses on the IGF system, we have correlated the drug serum levels attained after 2 months of either placebo (n = 32), tamoxifen 20 mg/day (n = 26), 10 mg/day (n = 23) or 10 mg/every other day (n = 29) with the changes in IGF-I, Insulin-like Growth Factor-II (IGF-II), Insulin-like Growth Factor Binding Protein-1 (IGFBP-1), Insulin-like Growth Factor Binding Protein-3 (IGFBP-3), and IGF-I/IGFBP-3 ratio. Compared with placebo, tamoxifen induced a mean +/- standard error (SE) reduction of IGF-I of 16.9 +/- 7.8%, p < 0.05, a non-significant increase of 22.9 +/- 12.2% in IGF-II, an increase in IGFBP-1 of 49.3 +/- 22.7%, p < 0.05, and a non-significant change of IGFBP-3 (-4.0% +/- 9.2). No significant concentration-response relationship was observed between serum tamoxifen concentrations and the biomarker changes except for the ratio of IGF-I/IGFBP-3, which decreased by 1.53 +/- 0.68% for any increase by 10 ng/ml of serum tamoxifen concentration (p = 0.02). Although low tamoxifen concentrations induce a comparable modulation of the IGF family relative to the conventional dose, the lower decrements in the IGF-I/IGFBP-3 ratio observed at low drug concentrations might be associated with a reduced preventive activity. Further studies on the search of the minimal active dose of tamoxifen are warranted.

Correlation between tamoxifen elimination and biomarker recovery in a primary prevention trial

We have shown previously that a reduction from the conventional dose of tamoxifen is associated with a comparable modulation of circulating biomarkers, including insulin-like growth factor-I and cholesterol. In the present study, we have correlated serum tamoxifen elimination with biomarker recovery in healthy subjects completing a 5-year intervention period. Tamoxifen, N-desmethyltamoxifen, and biomarker levels were measured at 0 (baseline), 2, 4, and 6 weeks after completion of treatment in 23 healthy postmenopausal women allocated to tamoxifen 20 mg/day and in 6 women allocated to placebo. Mean (+/-SD) serum tamoxifen and N-desmethyltamoxifen concentrations were, respectively, 141 +/- 50 and 226 +/- 77 ng/ml at baseline, 36 +/- 19 and 99 +/- 46 at 2 weeks, 20 +/- 15 and 61 +/- 37 at 4 weeks, and 12 +/- 9 and 36 +/- 26 at 6 weeks. Serum tamoxifen and N-desmethyltamoxifen half-lives were 9 and 13 days, respectively. Body mass index was associated positively with drug's serum half-life. Compared with baseline values, the percentage increase in total cholesterol, low-density lipoprotein cholesterol, and insulin-like growth factor-I 4 weeks after treatment completion was 5, 9, and 14%, respectively. No change during the 6-week period was observed in the placebo arm. Our findings indicate that the biomarker recovery is slower than serum tamoxifen elimination, suggesting that low tamoxifen concentrations may still exert a biological effect. In addition, the prolonged half-life of tamoxifen and metabolite provides the rationale for a weekly administration of the drug in a preventive context. However, the clinical implications of our findings remain to be defined.

Safety of the synthetic retinoid fenretinide: long-term results from a controlled clinical trial for the prevention of contralateral breast cancer

PURPOSE

To describe the pattern of occurrence of adverse events commonly arising during treatment with fenretinide, a synthetic retinoid under investigation for cancer prevention.

PATIENTS AND METHODS

The series includes 2,867 women accrued in a trial aimed at assessing the effect of fenretinide on the prevention of second breast malignancy. Women were randomly assigned to receive no treatment (1,435 patients) or 5-year fenretinide treatment (1,432 patients). In terms of disease recurrence in the breast, the trial showed a possible beneficial effect of the compound in premenopausal women, and an opposite trend in postmenopausal women. End points considered for safety assessment were the occurrence of diminished dark adaptation, dermatologic disorders, gastrointestinal symptoms, disorders of the ocular surface, and abnormal laboratory values.

RESULTS

The most common adverse events were diminished dark adaptation (cumulative incidence, 19.0%) and dermatologic disorders (18.6%). Less common events were gastrointestinal symptoms (13.0%) and disorders of the ocular surface (10.9%). In comparison, incidence figures in the control arm were 2.9% for diminished dark adaptation, 2.9% for dermatologic disorders, 5.4% for gastrointestinal symptoms, and 3.2% for disorders of the ocular surface. Symptoms occurring during fenretinide treatment tended to recover with time. No between-group difference was observed for the occurrence of laboratory data abnormalities. Overall, 63 (4.4%) treatment discontinuations were caused by adverse events.

CONCLUSION

Given the number of patients involved in the study and the prolonged intake of the drug, the experience on fenretinide tolerability can be considered sufficiently reassuring to justify further testing of the retinoid.

Ocular effects of fenretinide, a vitamin A analog, in a chemoprevention trial of bladder cancer

Fenretinide is a vitamin A derivative under investigation in cancer prevention trials. Because all available pharmacologic and toxicologic data were obtained from breast cancer patients, we measured plasma drug, metabolite, and vitamin A levels and studied their relationship with visual and ocular symptoms in a cohort formed mostly by male subjects belonging to a bladder cancer prevention trial. After 1 year, the mean plasma retinol levels (+/- standard deviation [SD]) were 168.2 +/- 75.8 ng/ml in 31 subjects treated with fenretinide and 594.5 +/- 168.4 ng/ml in 36 control subjects (P < .001). Plasma retinol levels were correlated inversely to drug and metabolite concentrations, which in turn were correlated inversely to the interval from last drug intake. The decline of plasma vitamin A levels accounted for a 41.7% cumulative incidence of diminished dark adaptability in the retinoid arm as compared to 6.8% in the control arm (odds ratio = 13.8; 95% confidence interval, 2.9-66.1). Although compliance as assessed by capsule count was high, three subjects originally assigned to the treatment group who proved to be noncompliers (8.8%, or 3 of 34) had no detectable plasma drug or metabolite levels. Our data confirm the specific pharmacologic and visual effects of fenretinide also in a male population and strengthen the importance of multiple blood measurements to monitor treatment compliance in prevention trials.

Randomized trial of fenretinide in superficial bladder cancer using DNA flow cytometry as an intermediate end point

Retinoids have shown a potential activity in preventing tumor recurrence in superficial bladder cancer. We assessed the activity of the synthetic retinoid fenretinide in superficial bladder cancer using DNA flow cytometry and conventional cytology as surrogate biomarkers. A total of 99 subjects with resected superficial bladder cancer (pTa, pT1) were randomized to either fenretinide (200 mg day p.o. for 24 months) or no intervention. Cystoscopy and bladder washing for DNA flow cytometry end points (proportion of DNA aneuploid histograms, hyperdiploid fraction, and percentage of apoptotic cells) and proportion of abnormal cytological examinations were repeated every 4 months for up to 36 months. The primary study end point was the proportion of DNA aneuploid histograms after 12 months. This figure was 48.9% in the fenretinide arm and 41.9% in the control arm (odds ratio, 1.16; 95% confidence interval, 0.44-3.07). There was no difference in any other response biomarker between the two groups up to 36 months, nor was any biomarker able to predict recurrence risk. Recurrence-free survival was comparable between the arms (27 events in the fenretinide arm versus 21 in the control arm; P = 0.36). Twelve subjects in the fenretinide arm complained of diminished dark adaptability, and nine subjects in the fenretinide arm versus one control subject had mild dermatological alterations. We conclude that fenretinide showed a lack of effect on the DNA content distribution and the morphology of urothelial cells obtained in serial bladder washings. Recurrence-free survival was comparable between groups. Because our data are hampered by the lack of predictivity of the selected biomarkers, additional studies are necessary to assess the activity of fenretinide in preventing bladder cancer.

Time course of fenretinide-induced modulation of circulating insulin-like growth factor (IGF)-i, IGF-II and IGFBP-3 in a bladder cancer chemoprevention trial

The insulin-like growth factor (IGF) system is widely involved in human carcinogenesis. A significant association between high circulating IGF-I concentrations and an increased risk of lung, colon, prostate and pre-menopausal breast cancer has recently been reported. Lowering plasma IGF-I may thus represent an attractive strategy to be pursued for chemopreventive purposes. We have previously shown that the synthetic retinoid fenretinide (4-HPR) lowers plasma IGF-I in pre-menopausal breast cancer patients. We investigated the effect of fenretinide on circulating IGF-I, IGF-II and IGFBP-3 measured at yearly intervals during the 2-year treatment period and one year after treatment discontinuation in a predominantly male population of patients with superficial bladder cancer. Repeated measures analysis, after adjustment for age, body mass index (BMI) and year of study, showed a significant effect of fenretinide on IGF-I levels, which were further lowered after the second year of treatment and only partially recovered after drug discontinuation. Differently from breast cancer patients, the effect of fenretinide was not modified by age. No significant effect was evident on IGFBP-3, IGF-II and the IGF-I+IGF-II/IGFBP-3 molar ratio, expressing the tissue availability of the mitogenic peptides, although IGF-II and the molar ratio were lowered by treatment by an overall mean of 16% and 15%, respectively. Given the increasingly recognized importance of circulating IGFs in the pathogenesis of different solid tumors, our findings strengthen the rationale for studying fenretinide as a chemopreventive agent.

Time course of fenretinide-induced modulation of circulating insulin-like growth factor (IGF)-i, IGF-II and IGFBP-3 in a bladder cancer chemoprevention trial

The insulin-like growth factor (IGF) system is widely involved in human carcinogenesis. A significant association between high circulating IGF-I concentrations and an increased risk of lung, colon, prostate and pre-menopausal breast cancer has recently been reported. Lowering plasma IGF-I may thus represent an attractive strategy to be pursued for chemopreventive purposes. We have previously shown that the synthetic retinoid fenretinide (4-HPR) lowers plasma IGF-I in pre-menopausal breast cancer patients. We investigated the effect of fenretinide on circulating IGF-I, IGF-II and IGFBP-3 measured at yearly intervals during the 2-year treatment period and one year after treatment discontinuation in a predominantly male population of patients with superficial bladder cancer. Repeated measures analysis, after adjustment for age, body mass index (BMI) and year of study, showed a significant effect of fenretinide on IGF-I levels, which were further lowered after the second year of treatment and only partially recovered after drug discontinuation. Differently from breast cancer patients, the effect of fenretinide was not modified by age. No significant effect was evident on IGFBP-3, IGF-II and the IGF-I+IGF-II/IGFBP-3 molar ratio, expressing the tissue availability of the mitogenic peptides, although IGF-II and the molar ratio were lowered by treatment by an overall mean of 16% and 15%, respectively. Given the increasingly recognized importance of circulating IGFs in the pathogenesis of different solid tumors, our findings strengthen the rationale for studying fenretinide as a chemopreventive agent.

Chemoprevention of breast cancer: the Italian experience

The activity of our group is focused on the conduction of chemoprevention clinical trials of breast cancer in at-risk subjects, among which we include women on hormone replacement therapy (HRT). The role of the insulin-like growth factor (IGF) system and of mammographic breast density as surrogate biomarkers for breast cancer prevention is also being investigated. The IGF system is involved in human carcinogenesis of several solid tumors. IGF-I is a potent mitogen for breast cancer cells; elevated circulating IGF-I levels have been associated with a higher risk of premenopausal breast cancer, prostate and colorectal cancer in prospective studies. Both tamoxifen and the synthetic retinoid fenretinide (4-HPR) have been shown to decrease plasma IGF-I levels. A trial of their combination is ongoing in premenopausal women with increased risk for breast cancer. Mammographic breast density has also been associated with an increased risk of breast cancer in several prospective studies. In this article, we discuss the rationale for selection of appropriate cohorts, candidate agents, and putative surrogate biomarkers in our breast cancer prevention trials. Moreover, updated results of the secondary prevention trial of 4-H PR and of the primary prevention trial of tamoxifen are presented. Finally, the rationale for a reduction of tamoxifen dose in future prevention trials is provided.

Fenretinide and cancer prevention

A characteristic feature of fenretinide is the ability to inhibit cell growth through the induction of apoptosis with mechanisms that may be both receptor-dependent and receptor-independent. Chemopreventive efficacy of fenretinide has been investigated in clinical trials targeted at different organs. Results of a phase III secondary prevention trial suggest a benefit in preventing second breast malignancies in premenopausal women with early breast cancer. A potential benefit of fenretinide with ovarian cancer and a reduction of new occurrences of leukoplakia have also been observed in clinical trials with this agent. However, no effects on DNA content of urothelial cells from bladder washings and on recurrence rate were noted in a study of patients with superficial bladder tumors. Future trials using surrogate biomarkers may aid in rapid evaluation of the chemopreventive activity of fenretinide with various targeted organs.