Role of combined-modality therapy in the management of locally advanced rectal cancer

Examination of the ovotoxicity of 5-fluorouracil in mice

PURPOSE

Undesirable side effects of cancer treatments are common and include damage to the ovary, and depletion of the follicle reserve, which if severe enough, can lead to infertility and early menopause. Antimetabolite drugs, such as 5-fluorouracil (5-FU), are not considered to be detrimental to the ovary, but the ovotoxicity of 5-FU has not been evaluated in any detail. The purpose of this study was to evaluate the effects of 5-FU on follicle number.

METHODS

In this study, adult female C57Bl6 mice (n = 4-6 animals/group) received a single dose of saline or 5-FU (150 mg/kg) and markers of ovarian damage and follicle depletion were assessed 12 h and 7 days later.

RESULTS

Exposure to 5-FU did not alter primordial and primary follicle numbers. Atresia of secondary and antral follicles was increased significantly 12 h after 5-FU treatment, but atresia rates returned to levels similar to that of saline treated controls at 7 days. The number of corpora lutea were reduced 7 days after exposure to 5-FU, possibly as a consequence of earlier follicular atresia.

CONCLUSIONS

These findings suggest that a single dose of 5-FU is mildly ovotoxic, but any effects on ovarian function are likely transient because the primordial follicle population is not depleted. Collectively, these data support the notion that 5-FU is unlikely to impact on the long-term fertility of women.

Kinetically guided neoadjuvant chemoradiotherapy based on 5-Fluorouracil in patients with locally advanced rectal cancer

BACKGROUND AND PURPOSE

This study estimated patients' early response following neoadjuvant chemoradiotherapy (CHRT) of locally advanced rectal cancer based on 5-fluorouracil (5-FU). The target was to achieve pathological complete response (pCR; residual disease-free stage) and toxicities of grade ≤2, using individual dosing predicted according to the steady-state plasma concentration (C ss) and pharmacokinetic parameters of 5-FU: the area under the time-concentration curve at steady state (AUC) and clearance (CL).

PATIENTS AND METHODS

This open-label prospective study enrolled 33 adult patients treated with 5-FU administered as a continuous intravenous infusion over 4-5 weeks, as follows: in Group 1a (N = 6), the patients received a standard dose of 300 mg/m(2)/24 h. In Group 1b (N = 7), the patients were treated with an escalated dose of 400-1,000 mg/m(2)/24 h. In Group 2 (N = 20), the patients were given dosing kinetically guided in order to reach the target range of 5-FU C ss 50-100 µg/L. Tolerability was tested according to Common Terminology Criteria for Adverse Events v3.0 (CTCAE). Radiotherapy was delivered with 10-15 MV photon beams at 1.8 Gy/fraction up to 50.4 Gy in 28 daily fractions for 5 days a week. Surgery followed 4-6 weeks after the completion of CHRT and clinical restaging. The pCR and residual tumour stage were evaluated using preoperative tumour downstaging in magnetic resonance, postoperative histopathological staging and tumour regression rate (residual disease).

RESULTS AND CONCLUSION

The cumulative AUC of 5-FU (total exposure to the drug) correlated with cumulative 5-FU dose (r = 0.61; p < 0.001) and residual disease (r s = -0.53; p < 0.005). A higher target pCR rate was reached in patients individually treated (Group 2) who finished the whole 5-week CHRT. The individual daily dose needed to reach the target C ss should be >350 mg/m(2) (up to 600 mg/m(2)) provided that 5-FU metabolic ratio is within the range of 2.5-6 and the cumulative AUC5wks is within 50-100 mg·h/L.

Comparative analysis of late functional outcome following preoperative radiation therapy or chemoradiotherapy and surgery or surgery alone in rectal cancer

PURPOSE

This study evaluates the anorectal and genitourinary function of patients treated by preoperative short-term radiotherapy (RT) or chemoradiotherapy (CRT) followed by surgery and surgery alone for rectal cancer.

METHODS

For this study, a total of 613 patients, who were identified from a prospective rectal cancer database, underwent anterior resection of the rectum between October 2001 and December 2007. Standardized questionnaires were used to determine fecal incontinence, urinary, and sexual function. Relevant clinical variables were evaluated using univariate and multivariate analyses. Independent predictors of functional outcome were identified by a binary logistic regression analysis.

RESULTS

The data of 263 (43 %) patients were available for analysis. On multivariate analysis, neoadjuvant RT (P < 0.01) and low anterior resection (LAR) (P = 0.049) were associated with fecal incontinence. In univariate analysis, fecal incontinence was linked to preoperative neoadjuvant treatment (RT and/or CRT vs. LAR) (P < 0.01). The hazard ratio for developing fecal incontinence was 3.3 (1.6-6.8) for patients who received RT. One hundred twenty-five patients (51.2 %) experienced urinary incontinence following surgery, the majority of whom were female (P < 0.01). On univariate analysis, male sexual function was associated with age (P < 0.01), ASA class (P = 0.01) and LAR (P = 0.01).

CONCLUSION

Multimodal therapy of low rectal cancer increases the incidence of fecal incontinence and negatively affects sexual function. The potential benefits of RT or CRT need to be balanced against the risk of increased bowel dysfunction when determining the appropriate treatment for individual patients with rectal cancer.

Multimodal treatment strategies for locally advanced rectal cancer

This review outlines the important multimodal treatment issues associated with locally advanced rectal cancer. Changes to chemotherapy and radiation schema, as well as modern surgical approaches, have led to a revolution in the management of this disease but the morbidity and mortality remains high. Adequate treatment is dependent on precise preoperative staging modalities. Advances in staging via endorectal ultrasound, computed tomography, MRI and PET have improved pretreatment triage and management. Important prognostic factors and their impact for this disease are under investigation. Here we discuss the different treatment options including modern tumor-related surgical approaches, neoadjuvant as well as adjuvant therapies. Further clinical progress will largely depend on the broader implementation of multidisciplinary treatment strategies following the principles of evidence-based medicine.

Topic update: effects of colorectal cancer treatments on female fertility and potential methods for fertility preservation

PURPOSE

Preservation of fertility in young females with a diagnosis of colorectal cancer is gaining increasing importance as survival rates of cancer increase. This review examines the effects of pelvic surgery, chemotherapy, and radiotherapy on fecundity. It also discusses the options available to patients including ovarian transposition, gonadotropin-releasing hormone analogs, embryo and ovarian cryopreservation, and ovarian tissue transplantation.

METHODS

A search of MEDLINE, EMBASE, and the Cochrane library was performed using keywords and exploded Mesh search headings and the subsequent articles were reviewed. Relevant studies were included.

RESULTS

There are no studies that examine the effect of surgery for colorectal cancer on female fertility, in particular, surgery below the peritoneal reflection for rectal cancer. However, patients with familial adenomatous polyposis have a similar fecundity before and after proctocolectomy with ileal pouch-anal anastomosis. These patients did significantly better than patients with ulcerative colitis who underwent the same procedure. There is conflicting evidence regarding the effects of open vs laparoscopic surgery on fertility. Oxaliplatin, an adjuvant therapy, has moderate gonadotoxic effects. Fluorouracil is considered to have almost no effect on human reproductive function. Gonadotropin-releasing hormone agonists are currently used to preserve female fecundity during chemotherapy. A recent update of patients treated for Hodgkin lymphoma showed that significantly fewer women treated with a gonadotropin-releasing hormone agonist during chemotherapy exhibited premature ovarian failure. Ovarian transposition reduces the radiation dose to approximately 5% to 10% of the dose to the ovaries in their normal position. Other options are available to women with cancer who wish to preserve their germ line, including embryo and oocyte cryopreservation and ovarian tissue cryopreservation.

CONCLUSION

Significant advances are now allowing females to preserve their fertility after cancer treatment. It is essential that patients receive adequate fertility counseling before any intervention to give them an opportunity to consider fertility alternatives.

Extended surgery and pelvic exenteration for locally advanced rectal cancer. What are the limits?

Historically, locally advanced rectal cancers with invasion of tumor into adjacent organs (T4 N1, 2 tumors) have been considered poor prognosis cancers treated with palliative intent. However with the advent of multi-modality therapy and improvement in surgical reconstructive techniques, extended resections for rectal tumors are possible with acceptable patient morbidity and excellent oncological outcomes.

Annual report to the nation on the status of cancer, 1975-2006, featuring colorectal cancer trends and impact of interventions (risk factors, screening, and treatment) to reduce future rates

BACKGROUND

The American Cancer Society, the Centers for Disease Control and Prevention (CDC), the National Cancer Institute (NCI), and the North American Association of Central Cancer Registries (NAACCR) collaborate annually to provide updated information regarding cancer occurrence and trends in the United States. This year's report includes trends in colorectal cancer (CRC) incidence and death rates and highlights the use of microsimulation modeling as a tool for interpreting past trends and projecting future trends to assist in cancer control planning and policy decisions.

METHODS

Information regarding invasive cancers was obtained from the NCI, CDC, and NAACCR; and information on deaths was obtained from the CDC's National Center for Health Statistics. Annual percentage changes in the age-standardized incidence and death rates (based on the year 2000 US population standard) for all cancers combined and for the top 15 cancers were estimated by joinpoint analysis of long-term trends (1975-2006) and for short-term fixed-interval trends (1997-2006). All statistical tests were 2-sided.

RESULTS

Both incidence and death rates from all cancers combined significantly declined (P < .05) in the most recent time period for men and women overall and for most racial and ethnic populations. These decreases were driven largely by declines in both incidence and death rates for the 3 most common cancers in men (ie, lung and prostate cancers and CRC) and for 2 of the 3 leading cancers in women (ie, breast cancer and CRC). The long-term trends for lung cancer mortality in women had smaller and smaller increases until 2003, when there was a change to a nonsignificant decline. Microsimulation modeling demonstrates that declines in CRC death rates are consistent with a relatively large contribution from screening and with a smaller but demonstrable impact of risk factor reductions and improved treatments. These declines are projected to continue if risk factor modification, screening, and treatment remain at current rates, but they could be accelerated further with favorable trends in risk factors and higher utilization of screening and optimal treatment.

CONCLUSIONS

Although the decrease in overall cancer incidence and death rates is encouraging, rising incidence and mortality for some cancers are of concern.

Annual report to the nation on the status of cancer, 1975-2006, featuring colorectal cancer trends and impact of interventions (risk factors, screening, and treatment) to reduce future rates

BACKGROUND

The American Cancer Society, the Centers for Disease Control and Prevention (CDC), the National Cancer Institute (NCI), and the North American Association of Central Cancer Registries (NAACCR) collaborate annually to provide updated information regarding cancer occurrence and trends in the United States. This year's report includes trends in colorectal cancer (CRC) incidence and death rates and highlights the use of microsimulation modeling as a tool for interpreting past trends and projecting future trends to assist in cancer control planning and policy decisions.

METHODS

Information regarding invasive cancers was obtained from the NCI, CDC, and NAACCR; and information on deaths was obtained from the CDC's National Center for Health Statistics. Annual percentage changes in the age-standardized incidence and death rates (based on the year 2000 US population standard) for all cancers combined and for the top 15 cancers were estimated by joinpoint analysis of long-term trends (1975-2006) and for short-term fixed-interval trends (1997-2006). All statistical tests were 2-sided.

RESULTS

Both incidence and death rates from all cancers combined significantly declined (P < .05) in the most recent time period for men and women overall and for most racial and ethnic populations. These decreases were driven largely by declines in both incidence and death rates for the 3 most common cancers in men (ie, lung and prostate cancers and CRC) and for 2 of the 3 leading cancers in women (ie, breast cancer and CRC). The long-term trends for lung cancer mortality in women had smaller and smaller increases until 2003, when there was a change to a nonsignificant decline. Microsimulation modeling demonstrates that declines in CRC death rates are consistent with a relatively large contribution from screening and with a smaller but demonstrable impact of risk factor reductions and improved treatments. These declines are projected to continue if risk factor modification, screening, and treatment remain at current rates, but they could be accelerated further with favorable trends in risk factors and higher utilization of screening and optimal treatment.

CONCLUSIONS

Although the decrease in overall cancer incidence and death rates is encouraging, rising incidence and mortality for some cancers are of concern.

Fertility preservation for young women with rectal cancer--a combined approach from one referral center

BACKGROUND

Up to 6% of women with colorectal cancer are diagnosed in the reproductive age and are at risk for premature ovarian failure and infertility due to pelvic irradiation and chemotherapy.

STUDY DESIGN

Between 1997 and 2007, six women with rectal carcinoma were referred to the McGill Reproductive Center (Montreal, Canada) for fertility preservation. Following resection of their primary tumor, they were scheduled to undergo pelvic irradiation.

RESULTS

Five patients underwent laparoscopic ovarian lateral transposition before radiotherapy in order to relocate their ovaries outside the radiation field. A concomitant ovarian wedge resection was performed for ovarian cryopreservation. In two of these women, before dissecting the ovarian cortical tissue for cryopreservation, all visible follicles were aspirated. The sixth patient who had had low anterior resection underwent hormonal ovarian stimulation followed by oocyte retrieval and embryo vitrification.

CONCLUSIONS

Fertility preservation in women with rectal cancer is feasible. This includes laparoscopic ovarian transposition and cryopreservation of ovarian tissue, embryo, or oocyte.