NCI Cancer Bulletin: A Trusted Source for Cancer Research NewsNCI Cancer Bulletin: A Trusted Source for Cancer Research News
November 21, 2006 • Volume 3 / Number 45 E-Mail This Document  |  Download PDF  |  Bulletin Archive/Search  |  Subscribe

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Cancer Research HighlightsCancer Research Highlights

Despite Guidelines, PSA Testing Is Common in Elderly Veterans

Many clinicians in the U.S. Department of Veterans Affairs medical system have been ordering prostate-specific antigen (PSA) screening for elderly men. In 2003, 56 percent of nearly 600,000 elderly male veterans had a PSA test performed, even though most guidelines recommend against the blood test for older men who have limited life expectancies because the known harms of prostate-cancer screening outweigh the potential benefits.

PSA screening rates in this population should be much lower than current levels, reported Dr. Louise Walter of the University of California, San Francisco, and her colleagues in the November 15 Journal of the American Medical Association (JAMA). For many men in poor health, screening is more likely to harm them than help them. The study included veterans aged 70 years or older who had no history of prostate cancer, elevated PSA, or prostate cancer symptoms. They were seen at 104 VA facilities.

Men with worsening health were screened at roughly the same rates as men in the best health. Factors such as marital status and region of the country were more important than health in determining screening. The rates for some subgroups of men in the worst health exceeded 60 percent.

An editorial noted that one reason for the high rates is that most men are overly optimistic about their own longevity. Another is that "patients often overestimate both the risk posed by the prostate cancer and the efficacy of treatment," wrote Dr. Peter Albertsen of the University of Connecticut Health Center.

Younger Women Fare Better than Older Women with Ovarian Cancer

Research has shown mixed results when it comes to age and prognosis after ovarian cancer. But a study, appearing early online this month in the British Journal of Cancer, lends the statistical strength of NCI's Surveillance, Epidemiology, and End Results (SEER) Program to results showing that younger women have a clear survival advantage compared with older women. Furthermore, younger women who receive uterine-sparing treatment do just as well as women who have standard surgery to treat the disease.

The study includes a nationally representative sample of 28,165 women who were diagnosed with epithelial ovarian cancer between 1988 and 2001. The women were divided according to age groups "very young" (<30 years old), "young" (30 to 60 years old), and "older" (>60 years old), as well as by race, cancer stage, grade, and type of treatment they received - uterine-sparing surgeries versus hysterectomy and/or radical debulking.

The overall 5-year survival for very young, young, and older women was 78.8 percent, 58.8 percent, and 35.3 percent, respectively, with similar trends for early- and late-stage disease. Younger women tended to be diagnosed with early-stage disease more often than older women, and they also received surgery more often, usually a uterine-preserving procedure (71.2 percent versus 14.1 percent and 15.6 percent). Women aged 16 to 40 who had these uterine-sparing procedures had similar survival to women of the same ages who had standard surgery (93.3 percent versus 91.5 percent). "Younger age continues to portend for a better prognosis across ethnic, histologic cell types, and year of diagnosis," the authors wrote, advising that "reproductive-age women who undergo surgical staging should be offered conservative treatment with uterine-sparing surgeries…[and] be treated aggressively."

Adjuvant Radiotherapy Reduces Advanced Prostate Cancer Recurrence

Patients with pathologically advanced prostate cancer who received immediate adjuvant radiotherapy following radical prostatectomy had a significantly reduced risk of PSA relapse, according to a study published in the November 15 JAMA.

A total of 425 men were enrolled into the multi-institutional study conducted by the Southwest Oncology Group, and were randomly assigned to either external beam radiotherapy or usual care plus observation. Patients were enrolled between 1988 and 1997, and were followed for a median of 10.6 years.

Although the reduction in the risk of cancer spread to distant sites was not significantly different between the two arms, the study showed that adjuvant radiotherapy significantly lowers the risk of cancer recurrence as indicated by PSA relapse. Median PSA relapse-free survival in the observation group was 3.1 years compared with a median PSA relapse-free survival of 10.3 years in the group receiving adjuvant radiation therapy.

PSA relapse may be an early indication of disease relapse and is associated with considerable patient anxiety. Dr. Bhadrasain Vikram, chief of the Clinical Radiation Oncology Branch in NCI's Division of Cancer Treatment and Diagnosis (DCTD), commented that "If, after the operation, cancer is found to extend beyond the prostate - but not into the lymph nodes - radiation treatment may decrease recurrences. But, radiation also increased the risk of side effects, especially problems with urination."

Future research questions raised by this study include whether radiotherapy is better delivered immediately post-operatively or at time of PSA recurrence which would spare some patients unnecessary treatment, and whether metastatic disease could be significantly affected by identifying and treating subsets of higher risk patients.

Dr. Vikram commented, "In 1988, when this study began, the surgeons' ability to select for operation men with cancer truly confined to the prostate was much less refined. With all the information that is available today prior to surgery, very few men should have cancer found beyond the prostate. For those who do, this study offers valuable information about what to expect, and that should help in deciding the best course of action."

Primary Care Physicians Are Low Prescribers of Tamoxifen

Only a minority of primary care physicians have prescribed tamoxifen for breast cancer prevention since its approval for that use in 1998, and a woman's increased risk of endometrial cancer or blood clots from tamoxifen seems to have less effect on prescribing decisions than other factors, according to a study published online November 13 in the Archives of Internal Medicine.

Although tamoxifen has been shown to greatly reduce the incidence of breast cancer among high-risk women, it also has significant adverse effects, including a twofold increase in the risks of venous thromboembolism and endometrial cancer.

In a study of prescribing habits of 350 primary care physicians, University of Pennsylvania researchers found that only 27 percent had prescribed the drug for breast cancer prevention in the past 12 months. The results indicate that prescription of tamoxifen by primary care physicians is strongly associated with logistical factors, such as patient demand and the physician's ability to determine a patient's risk for developing breast cancer. In addition, "physicians with a family member with breast cancer (usually their mother) were more than two times more likely to have prescribed tamoxifen to a patient than physicians without a family member with breast cancer," the researchers reported.

Decisions to prescribe tamoxifen were not correlated with concerns about endometrial cancer or thromboembolism, the scientists found. "Although we did not explore the reasons for this discrepancy, it is possible that it reflects the perception that endometrial cancer is largely a curable disease and that this finding would not be true for other drugs with different adverse effects," they noted.

Combination of Therapies Shows Promise for Cervical Cancer

A new study from the University of Pittsburgh presented at the 2006 American Society for Therapeutic Radiation and Oncology meeting in Philadelphia assessed the addition of both irradiation of the para-aortic lymph nodes (located above the pelvis) and chemotherapy to pelvic radiation therapy for cervical cancer. Because previous trials of this combination have shown excessive toxicity, this study used intensity-modulated radiation therapy (IMRT) to include the para-aortic lymph nodes in the radiation field. IMRT reduces radiation damage to nearby healthy tissue.

Investigators enrolled 36 patients with cervical cancer into the study. In 19 of these patients, cancer had spread to nearby lymph nodes. All patients received pelvic radiation therapy (including brachytherapy in all but two patients), irradiation of the para-aortic lymph nodes, and weekly low-dose chemotherapy with cisplatin.

One patient experienced high-grade gastrointestinal toxicity, and one experienced high-grade genitourinary toxicity. A high-grade decrease in bone marrow activity was seen in 10 patients. All patients completed radiation therapy; only three could not complete the last cycle of chemotherapy.

Thirty-three patients had a complete response to the treatment, though 11 of them eventually developed recurrences during the follow-up period. None of these recurrences were in the para-aortic lymph nodes; most were due to distant metastases.

"These results are promising but inconclusive," stated Dr. Bhadrasain Vikram, from NCI's DCTD. "Further studies need a control group to compare safety with standard radiation therapy. Those must be followed by studies to determine whether the addition of para-aortic irradiation improves survival in comparison to chemotherapy and pelvic irradiation alone."