Retrospective radiographic analysis of nonpedunculated colorectal carcinomas with special reference to tumor doubling time and morphological change

Screening for Colorectal Cancer Using a Multitarget Stool DNA Test: Modeling the Effect of the Intertest Interval on Clinical Effectiveness

BACKGROUND

A multitarget stool DNA (mt-sDNA) test was recently approved for colorectal cancer (CRC) screening for men and women, aged ≥ 50 years, at average risk of CRC. The guidelines currently recommend a 3-year interval for mt-sDNA testing in the absence of empirical data. We used clinical effectiveness modeling to project decreases in CRC incidence and related mortality associated with mt-sDNA screening to help inform interval setting.

MATERIALS AND METHODS

The Archimedes model (Archimedes Inc., San Francisco, CA) was used to conduct a 5-arm, virtual, clinical screening study of a population of 200,000 virtual individuals to compare the clinical effectiveness of mt-sDNA screening at 1-, 3-, and 5-year intervals compared with colonoscopy at 10-year intervals and no screening for a 30-year period. The study endpoints were the decrease in CRC incidence and related mortality of each strategy versus no screening. Cost-effectiveness ratios (US dollars per quality-adjusted life year [QALY]) of mt-sDNA intervals were calculated versus no screening.

RESULTS

Compared with 10-year colonoscopy, annual mt-sDNA testing produced similar reductions in CRC incidence (65% vs. 63%) and related mortality (73% vs. 72%). mt-sDNA testing at 3-year intervals reduced the CRC incidence by 57% and CRC mortality by 67%, and mt-sDNA testing at 5-year intervals reduced the CRC incidence by 52% and CRC mortality by 62%. At an average price of $600 per test, the annual, 3-year, and 5-year mt-sDNA screening costs would be $20,178, $11,313, and $7388 per QALY, respectively, compared with no screening.

CONCLUSION

These data suggest that screening every 3 years using a multitarget mt-sDNA test provides reasonable performance at acceptable cost.

Development and progression of colorectal cancer based on follow-up analysis

Elucidating the pathway of colorectal cancer development and progression can lead to identification of lesions that must be treated appropriately. The aim of the present review was to summarize the development and progression of colorectal cancer based on radiological and endoscopic follow-up analyses. These studies revealed several characteristic findings, including that initial morphology with progression to advanced cancer was most commonly 0-Is, followed by 0-IIa. Based on the doubling time, 0-Ip grew slowly in comparison with other morphologies. The observation period from adenomas measuring <10 mm to intramucosal cancers was more than 5 years. This makes it difficult to draw any accurate conclusions about the natural history of colorectal cancer based on follow-up observation alone and it is difficult to exclude the selection bias because of the difficulty of follow up for flat and depressed tumor. However, the only reliable way to elucidate the natural history is to accumulate cases.

Health benefits and cost-effectiveness of a hybrid screening strategy for colorectal cancer

BACKGROUND & AIMS

Colorectal cancer (CRC) screening guidelines recommend screening schedules for each single type of test except for concurrent sigmoidoscopy and fecal occult blood test (FOBT). We investigated the cost-effectiveness of a hybrid screening strategy that was based on a fecal immunological test (FIT) and colonoscopy.

METHODS

We conducted a cost-effectiveness analysis by using the Archimedes Model to evaluate the effects of different CRC screening strategies on health outcomes and costs related to CRC in a population that represents members of Kaiser Permanente Northern California. The Archimedes Model is a large-scale simulation of human physiology, diseases, interventions, and health care systems. The CRC submodel in the Archimedes Model was derived from public databases, published epidemiologic studies, and clinical trials.

RESULTS

A hybrid screening strategy led to substantial reductions in CRC incidence and mortality, gains in quality-adjusted life years (QALYs), and reductions in costs, comparable with those of the best single-test strategies. Screening by annual FIT of patients 50-65 years old and then a single colonoscopy when they were 66 years old (FIT/COLOx1) reduced CRC incidence by 72% and gained 110 QALYs for every 1000 people during a period of 30 years, compared with no screening. Compared with annual FIT, FIT/COLOx1 gained 1400 QALYs/100,000 persons at an incremental cost of $9700/QALY gained and required 55% fewer FITs. Compared with FIT/COLOx1, colonoscopy at 10-year intervals gained 500 QALYs/100,000 at an incremental cost of $35,100/QALY gained but required 37% more colonoscopies. Over the ranges of parameters examined, the cost-effectiveness of hybrid screening strategies was slightly more sensitive to the adherence rate with colonoscopy than the adherence rate with yearly FIT. Uncertainties associated with estimates of FIT performance within a program setting and sensitivities for flat and right-sided lesions are expected to have significant impacts on the cost-effectiveness results.

CONCLUSIONS

In our simulation model, a strategy of annual or biennial FIT, beginning when patients are 50 years old, with a single colonoscopy when they are 66 years old, delivers clinical and economic outcomes similar to those of CRC screening by single-modality strategies, with a favorable impact on resources demand.

Morphological change of a laterally spreading rectal tumor over a short period

BACKGROUND

Laterally spreading tumors (LSTs) are generally defined as superficial lesions ≥10 mm in diameter that typically extend laterally rather than vertically along the colonic wall. LSTs are usually categorized into 2 subtypes: granular type and nongranular type. Large nodules or depressed areas in granular-type LSTs (LST-Gs) are endoscopic findings of a cancerous component and sometimes represent submucosal invasion. However, the lateral growth and development of LST-Gs remains unclear.

CASE PRESENTATION

This case report describes a case of 79-year-old woman who underwent total colonoscopy due to a positive fecal occult blood test and was detected a LST-G, about 30 mm in diameter in the lower rectum. The lesion consisted of not only aggregated small and large nodules typically seen in LST-Gs but also the hardly elevated flat parts. In the flat part, there were dilated round pits and no evident capillary vessels. Three months later, the flat part increased in height, the dilated round pits were partly replaced by type IIIL pits, and capillary vessels were evident. The lesion was removed by endoscopic submucosal dissection, and diagnosed pathologically as tubular adenoma. We performed the sequence analyses on KRAS, BRAF, NRAS and PIK3CA genes in flat part and nodular part separately, and a mutation of KRAS gene at codon 146 was observed at only nodular part, suggesting probable that nodular part be a precancerous lesion.

CONCLUSION

This is a unique and suggestive case, providing information on progression of LST-Gs at the very early stage to carcinogenesis.

Impact of comorbidity on colorectal cancer screening cost-effectiveness study in diabetic populations

BACKGROUND

Although comorbidity has been shown to affect the benefits and risks of colorectal cancer (CRC) screening, it has not been accounted for in prior cost-effectiveness analyses of CRC screening.

OBJECTIVE

To evaluate the impact of diagnosis of diabetes mellitus, a highly prevalent comorbidity in U.S. adults aged 50 and older, on health and economic outcomes of CRC screening.

DESIGN

Cost-effectiveness analysis using an integrated modeling framework.

DATA SOURCES

Derived from basic and epidemiologic studies, clinical trials, cancer registries, and a colonoscopy database.

TARGET POPULATION

U.S. 50-year-old population.

TIME HORIZON

Lifetime.

PERSPECTIVE

Costs are based on Medicare reimbursement rates.

INTERVENTIONS

Colonoscopy screening at ten-year intervals, beginning at age 50, and discontinued after age 50, 60, 70, 80 or death.

OUTCOME MEASURES

Health outcomes and cost effectiveness.

RESULTS OF BASE-CASE ANALYSIS

Diabetes diagnosis significantly affects cost-effectiveness of CRC screening. For the same CRC screening strategy, a person without diabetes at age 50 gained on average 0.07-0.13 life years more than a person diagnosed with diabetes at age 50 or younger. For a population of 1,000 patients diagnosed with diabetes at baseline, increasing stop age from 70 years to 80 years increased quality-adjusted life years (QALYs) gained by 0.3, with an incremental cost-effectiveness ratio of $206,671/QALY. The corresponding figures for 1,000 patients without diabetes are 2.3 QALYs and $46,957/QALY.

RESULTS OF SENSITIVITY ANALYSIS

Cost-effectiveness results are sensitive to cost of colonoscopy and adherence to colonoscopy screening.

LIMITATIONS

Results depend on accuracy of model assumptions.

CONCLUSION

Benefits of CRC screening differ substantially for patients with and without diabetes. Screening for CRC in patients diagnosed with diabetes at age 50 or younger is not cost-effective beyond age 70. Screening recommendations should be individualized based on the presence of comorbidities.

Inhibitors targeting mitosis: tales of how great drugs against a promising target were brought down by a flawed rationale

Although they have been advocated with an understandable enthusiasm, mitosis-specific agents such as inhibitors of mitotic kinases and kinesin spindle protein have not been successful clinically. These drugs were developed as agents that would build on the success of microtubule-targeting agents while avoiding the neurotoxicity that encumbers drugs such as taxanes and vinca alkaloids. The rationale for using mitosis-specific agents was based on the thesis that the clinical efficacy of microtubule-targeting agents could be ascribed to the induction of mitotic arrest. However, the latter concept, which has long been accepted as dogma, is likely important only in cell culture and rapidly growing preclinical models, and irrelevant in patient tumors, where interference with intracellular trafficking on microtubules is likely the principal mechanism of action. Here we review the preclinical and clinical data for a diverse group of inhibitors that target mitosis and identify the reasons why these highly specific, myelosuppressive compounds have failed to deliver on their promise.

The natural history of non-polypoid colorectal neoplasms

Despite their importance, little is known about the natural history of non-polypoid colorectal neoplasms (NP-CRN). This article will summarize the available data to gain some estimates of the natural history of NP-CRN.

Tools for making correct decisions regarding hormone therapy. Part II. organ response and clinical applications

OBJECTIVE

To review existing scientific knowledge of the complicated and variable behavior and response to hormone therapy (HT) of different organs during aging, and to summarize long-term consequences on human health.

DESIGN

A MEDLINE computer search was performed to identify relevant articles.

RESULT(S)

Five body organs were evaluated. [1]. Physiologic aging of the bone has deleterious consequences on women's health and quality of life. Bone fractures could be attributed to the combination of estrogen depletion and osteoporosis, mechanisms of applied forces, and disturbed brain function, partially reversible by timely estrogen administration. [2]. Estrogen seems to have a profound neuroprotective effect. As physiologic aging of the brain is an unhealthy phenomenon, possible intervention is justified. The therapeutic time window seems crucial. [3]. The differentiation between response of a healthy or already damaged organ to sex hormones is the key factor to understanding the possible cardioprotective effects. [4]. Based on doubling time of tumor cells, intracrinology, epidemiological data on breast cancer, and behavior of breast cancer survivors in response to estrogen treatment, estrogen seems to be mainly a promoter and even a protector of breast cancer survivors. [5]. Colon cancer appears to be an estrogen-dependent tumor with a wide therapeutic window, as every report regardless of age and dose demonstrates protective effects.

CONCLUSION(S)

Knowledge of each organ's response to aging and sex hormone substitutions demonstrates that the organs could benefit from properly designed intervention. In the wake of the publication of the Women's Health Initiative study, which shocked the medical community, we suggest that the results be reevaluated according to the aforementioned principles, and that menopausal medicine could play an important role.

Symptom duration versus survival in non-emergency colorectal cancer

BACKGROUND

Morbidity and mortality from colorectal cancer remain as major public health problems. Previous studies have demonstrated a lack of association between symptom duration and stage. Emergency cases are, however, known to present with a more advanced disease stage. This study was set up to define the effect of symptom duration on stage and survival separately in the elective population.

METHODS

Between 1998 and 1999, 228/235 (97%) eligible patients with recently diagnosed colorectal cancer in Västmanland County, Sweden were included in the study. A questionnaire was designed to collect information on the nature and date of first symptoms within two weeks' accuracy. Symptom duration could be categorized as more or less than 26 weeks for 164 (70%) patients. Data on type of admittance (elective or emergent), date of surgery, site and stage were retrieved from the surgical records. Survival was checked in November 2003 and Kaplan-Meier survival estimates were calculated.

RESULTS

Median symptom duration was 17 weeks, 20 in the elective and 13 in the emergency population (P < 0.01). In the elective population, median symptom duration for Dukes' A and B cancer was 19 compared with 21 weeks for Dukes' C and D cancer (mean difference in symptom duration 0.04 (95% CI-0.31; 0.23). Symptom duration did not influence overall survival in the non-emergency group (log rank 2.8; P = 0.09).

CONCLUSION

To diminish the impact of colorectal cancer on public health, strategies other than a shortening of symptom duration are needed.

Natural history of colorectal nonpolypoid adenomas: a prospective colonoscopic study and relation with cell kinetics and K-ras mutations

OBJECTIVE

Serial colonoscopic observations were prospectively conducted to elucidate the natural history of nonpolypoid tumors. Furthermore, to clarify whether cell kinetic status affects the tumor development, proliferative indices, apoptotic indices, and K-ras codon 12 point mutations on biopsy specimens were investigated.

METHODS

Seventy-five colorectal tumors, 13 polypoid and 62 nonpolypoid type (56 flat elevated and six depressed type) were studied. Proliferating and apoptotic cells were detected with anti-Ki-67 antibody and the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling method, respectively. Point mutations at K-ras codon 12 were examined by enriched polymerase chain reaction-based restriction fragment length polymorphism assay.

RESULTS

The average follow-up period was 22 months (range 1-50). The lesions of subsequent exophytic growth, unchanged shape, depressed growth, and disappearance were observed in 0%, 92%, 0%, and 8% of polypoid type, in 39%, 39%, 13%, and 9% of flat elevated type, and in 33%, 67%, 0%, and 0% of depressed type, respectively. There was no significant difference in tumor size between initial and follow-up colonoscopy. Nonpolypoid tumors apparently changed to the exophytic growth during 2 yr or more. The tumors with exophytic growth had significantly higher proliferative indices/apoptotic indices ratios than those with unchanged morphology and disappearance/depressed growth (p < 0.05, respectively). K-ras codon 12 point mutations did not correlate with tumor development.

CONCLUSIONS

Cell kinetic status plays an important role in determining minute colorectal tumor development, but not K-ras codon 12 mutations. Minute nonpolypoid adenomas frequently tend to grow slowly, and nearly 40% of those become the exophytic growth with time. Most of minute nonpolypoid tumors seem to follow the adenoma-carcinoma sequence.