In the February issue of the British Journal of Cancer, Dr. Niall C. Tebbutt of Austin Hospital, Heidelberg and colleagues conducted an Australian population-based study using a government insurance database covering 2002 and 2003 and involving almost 3000 patients.

In 2002, the team found that 48% of patients received initial treatment with oxaliplatin rather than irinotecan. However, 66% started with oxaliplatin in 2003, a significant increase.

In total, 40% to 45% of patients received treatment with both drugs. This was significantly more likely to be true of younger patients and survival was greater in this group.

Approximately 67% of F-5U refractory patients were estimated to survive for 6 months. The corresponding proportion at 1 year was 42%.

These survival findings were lower than those seen in clinical trials, where about 80% of subjects were alive at 6 months and more than 50% were alive at 1 year.

Nevertheless, the investigators point out that overall survival was similar, and that the difference may have been due to trial subjects being younger and fitter.

However, in clear contrast to clinical trial results, there was a higher survival in younger patients regardless of the type of initial treatment. This, the investigators conclude, may be “because clinicians treat older patients less intensively.”

Up to 10% of women who have received treatment for unilateral breast cancer have involvement of the other breast as well, according to the report in The New England Journal of Medicine for March 29. The focus of the present study was to determine if MRI evaluation can improve the detection of contralateral malignancies.

The study involved an MRI assessment of 969 women who were recently diagnosed with unilateral breast cancer and had no apparent disease in the opposite breast, according to mammography and clinical examination. MRI-detected breast cancer was confirmed with biopsy and the absence of disease on MRI was confirmed with biopsy, repeat imaging or both.

MRI detected cancer in the contralateral breast of 3.1% of the women, lead author Dr. Constance D. Lehman, from the University of Washington Medical Center in Seattle, and colleagues note. The sensitivity, specificity, and negative predictive value of MRI in detecting cancer in the contralateral breast were 91%, 88%, and 99%, respectively.

A positive MRI finding led to biopsy in 121 women (12.5%). Thirty of the specimens contained cancer, including 18 with invasive disease. The average diameter of the invasive tumors was 10.9 mm.

Breast density, menopausal status, or the histologic features of the primary tumor had no bearing on the additional number of cancers detected.

In a related editorial, Dr. Robert A. Smith, from the American Cancer Society in Atlanta, comments that it may be argued that the added sensitivity of MRI of the contralateral breast comes at high cost in terms of false-positive results and overdiagnosis. Nevertheless, the false positive rate and the predictive value of a positive test fall within an acceptable range, and there is little persuasive evidence that most cases of ductal carcinoma in situ are not progressive.”

“Therefore,” Dr. Smith concludes, “there is value in detecting and treating malignant tumors in the contralateral breast that were not identified by means of mammography and clinical breast examination.”

“Colorectal cancer is one of the most commonly diagnosed cancers worldwide, and dietary factors are considered to be important in its risk,” Dr. Song-Yi Park, of the University of Hawaii, Honolulu, and colleagues write. “A possible protective effect of calcium and vitamin D against colorectal carcinogenesis has been suggested from results of in vivo and in vitro studies.”

Dr. Park and co-investigators examined the association between calcium and vitamin D intake and the risk of colorectal cancer in 191,011 participants of the Multiethnic Cohort Study. The subjects were between the ages of 45 and 75 years, and completed a quantitative food frequency questionnaire between 1993 and 1996.

During an average follow-up of 7.3 years, a total of 2110 incidence cases of colorectal cancer were identified (1138 in men and 972 in women).

An inverse association was observed between total calcium intake (from food and supplements) and the risk of colorectal cancer in both men and women. The relative risks (RRs) for the highest versus the lowest quintile were 0.70 (p = 0.006) and 0.64 (p = 0.003) in men and women, respectively.

“Total vitamin D intake was inversely associated with colorectal cancer risk in men but not in women,” Dr. Park’s team reports. The RR for the highest quintile was 0.72 (p for trend = 0.03) in men and 0.89 (p for trend = 0.80) in women.

An inverse association was also found between intake of dairy products and colorectal cancer risk. This was especially true among nonusers of supplemental calcium — RR = 0.77 in men and RR = 0.66 in women.

“These findings support the hypothesis of protective roles for calcium, vitamin D and dairy products in the risk of colorectal cancer,” the researchers conclude.

As lead investigator Dr. Jennifer Lin said, “Our study suggests that exogenous hormone use such as oral contraceptives may confer some protection among women against colorectal cancer development.”

Dr. Lin of Harvard Medical School, Boston and colleagues evaluated associations of oral contraceptive use and reproductive factors and risk of colorectal cancer among 39,680 participants in the Women’s Health Study.

During an average of 11 years of follow-up there were 267 incident cases of colorectal cancer. Ever having used of oral contraceptives was associated with a lower risk of colorectal cancer (relative risk, 0.67).

For OC use from 6 months to less than 3 years, the relative risk was 0.61 There was little further decrease in risk with longer duration of use.

However, despite the apparent relationship with oral contraceptives, concluded Dr. Lin, “The association between endogenous production of sex hormones — reproductive factors — and colorectal cancer incidence remains unclear.”

The current findings contradict what was seen in previous studies, such as the Women’s Health Initiative. In those trials, vitamin D intake did not seem to protect against colorectal cancer. However, it is possible that the dose may simply have been too low to provide a benefit.

The present analysis, reported in the American Journal of Preventive Medicine for March, included data from five studies, identified through PubMed, that examined the association between serum 25(OH)D levels and colorectal cancer risk.

As serum levels of 25(OH)D rose, the risk of colorectal cancer fell, lead author Dr. Edward D. Gorham, from the Naval Health Research Center in San Diego, California, and colleagues note. Compared with the lowest serum level quintile (median 12 ng/mL), the highest quintile (median 37 ng/mL) cut the risk by 54% (p < 0.0001 for trend).

On the final pooled analysis, a serum 25(OH)D level of 33 ng/mL or higher was associated with a 50% decreased risk of colorectal cancer relative to a level of 12 ng/mL or lower.

The researchers believe that the target serum levels could be achieved with intake of 1000 to 2000 IU of vitamin D per day. Moreover, they note that the National Academy of Sciences has established that a dose of 2000 IU/day is safe.

Given these findings, senior investigator Dr. Linda Rabeneck said that “for the delivery of colonoscopy services in Ontario, we need to further study the practice of colonoscopy in offices and private clinics… There is something different about the practice of colonoscopy in these settings that gives rise to higher cancer miss rates, a worrisome finding.”

Dr. Rabeneck, of the University of Western Ontario, London and colleagues report their study of colorectal cancer patients in the province in the January issue of Gastroenterology.

Of 12,487 patients included, 430 (3.4%) had new or missed cancer, based on a diagnosis within 6 months to 3 years of having a colonoscopy. Reducing this period to 2 years yielded a 2.4% rate. An increase to 5 years gave a figure of 4.6%.

Further analysis showed that using the 3-year interval, right sided colorectal cancer was the most likely to be missed (5.9%). Older patient age and the presence of diverticular disease were also associated with missed cancers.

As mentioned, other independent risk factors were having colonoscopy by an internal medicine specialist or family physician and having had colonoscopy in an office.

Specifically, compared to hospital-based colonoscopy, having the procedure in an office yielded an adjusted odds ratio of new or missed colorectal cancer of 3.07 in men and 1.95 in women.

Compared to gastroenterologists, the odds ratio for missed cancers with family physicians or internists was 1.77 for men and 1.85 for women.

“For physicians performing colonoscopy, we need to advise our patients of the small chance that if they have a cancer we might miss it,” Dr. Rabeneck concluded, adding: “As we move forward with the Ontario colorectal cancer screening program, we will ensure that colonoscopy standards are implemented.”