Paris, France, Wednesday 2 November 2005 - Despite intensive efforts focused on detection and early treatment, in certain populations cervical cancer rates are rising and medical therapy remains inadequate, according to data presented at the 13th European Cancer Conference (ECCO).
In sub-Saharan Africa, insufficient radiotherapy appears to be hindering the survival prospects for women with cervical cancer, co-infected with HIV. Results from a pattern of care study carried out by the International Atomic Energy Agency in Uganda, Namibia, Tanzania and Zimbabwe show that inadequate radiotherapy proved more significant for patient survival during the first year than HIV status. Of the 147 women with biopsy-confirmed cervical cancer included in the study, 18.4% were found to be HIV-positive, yet this co-infection did not impact on survival rates. At 407 days, the median survival in HIV infected women was actually found to exceed that for HIV-negative patients. CD4 counts were temporarily depressed with radiotherapy but levels recovered after a few months and no detrimental effects were observed from concurrent administration to HIV-positive women.
Instead, what was found to be significant was the teletherapy dose patients received – this was associated with significant inter-country variability. Lowest levels were recorded in Zimbabwe (mean 22.4 Gy) where a machine breakdown actually resulted in 10 registered patients not receiving any radiotherapy whatsoever during the period studied. The highest radiotherapy doses were used in Namibia and Uganda (mean 50 Gy). Overall analysis revealed that patients receiving higher radiotherapy doses had a significantly greater survival advantage. These results imply that resource limitations which restrict the appropriate use of radiotherapy may be responsible the early deaths of women with cervical cancer in certain African nations, regardless of HIV status.
Dr Bhadrasain Vikram from the International Atomic Energy Agency, Austria commented, "There is a widespread perception that if a patient has both cancer and HIV the situation is hopeless. Our study found that this was clearly NOT true for cervix cancer IF the patient received proper radiotherapy for her cancer. If she did not receive proper radiotherapy, then a poor outcome became a self-fulfilling prophecy." In China, an epidemiological study has described a worrying trend in cervical cancer incidence rates among young women. Results from statistical analysis of the 22,224 cases of primary cervical cancer diagnosed at the Tianjin Cancer Registry between 1981 and 2000 were described at ECCO. Overall, there was a considerable decline in cervical cancer incidence rates, both crude and age-adjusted over the 9-year time timeframe assessed. Yet the changes in incidence rates were non consistent across age groups, with the 40+ age bracket showing the most marked contribution to the observed decline. In contrast, incidence rates in those aged 20-39 and younger, increased in the period from 1981 to 2000. A further undesirable finding was the apparent rebound in incidence rates towards the end of the study, with analysis showing a small upward tail in cervical cancer incidence approaching 2000.
These results are of concern for the future as they indicated that Chinese young women are no longer following the traditional lifestyles of their parents; yet they are pursuing modern lifestyles without the necessary health education to protect them against the risks of cervical cancers and other related diseases. The investigators of this study recommended developing targeted education strategies and more efficient screening programmes to help and protect the young population.
In addition to detection and treatment, prevention is an important component of any overall cervical cancer strategy. Particular focus lies with the human papilloma virus (HPV) as infection by oncogenic HPV types is a necessary cause of cervical cancer. GARDASIL is a quadrivalent vaccine against four HPV types, including those implicated in the pathogenesis of cervical cancer, anogenital warts and low-grade cervical lesions, currently undergoing clinical development. Baseline prevalence of Pap smear abnormalities in two pivotal clinical trials of this vaccine were revealed at ECCO. Overall, in this multi-ethnic, geographically diverse study population of 17,926 young women from Europe, Latin and North American and the Asia-Pacific region, with an average age of 20 years, abnormalities were identified in more than 1 in every 10 Pap smears. These findings underscore the potential value of an effective HPV vaccine given the established association of HPV with cervical lesions, especially those of higher grade.
Following on from Dr Paavonen's epidemiology study, results from clinical trials with GARDASIL showed significant protection from the human papilloma virus infection. Using CIN 2/3 and AIS obligate precursor lesions for cervical squamous cell and adeno-carcinoma respectively, prophylactic use of quadrivalent human papillomavirus (HPV) (Types 6,11,16,18) L1 virus-like particle (VLP) vaccine (GARDASIL) was found to reduce the incidence of these precursor lesions.
Four clinical trials were established to assess the effectiveness of GARDASIL against cervical cancer and CIN 1-3 and genital warts. 20,541 women were recruited from Americas, Europe and Asia. In one trial, subjects were randomised to either a monovalent HPV 16 L1 VLP vaccine or placebo and in the other three trials, subjects were randomised to either quadrivalent HPV (Types 6,11,16,18)L1 VLP vaccine or placebo. For all trials, vaccinations occurred at day 1 and months 2 and 6. Genital tract specimens for Pap and HPV DNA tests were obtained at day 1 and at 6-12 month intervals for a maximum of 48 months.
Results offered virtually 100% efficacy with prophylactic quadrivalent HPV vaccination (only 16 cases were included in the HPV 16 vaccine trial) in the prevention of HPV 16/18-related CIN 2/3 and AIS precursor lesions and consequent risk of cervical cancer.
Dr Kevin Ault from the Emory University Hospital, USA reported, "Cervical cancer is a unique cancer because nearly all cases are caused by a prior infection with human papilloma virus (HPV). Studies have shown that a potential vaccine for HPV may prevent cervical infection with HPV. Our study shows that these vaccines may prevent precancerous disease of the cervix. In the developing world, this vaccine has the potential of greatly reducing deaths due to this common cancer. Vaccines have been a very successful tool to prevent infectious disease, hopefully cervical cancer will join the list of diseases that can be prevented by vaccination."
About Cervical Cancer
Cervical cancer develops in the lining of the cervix. This condition can develop over time when normal cervical cells undergo changes to become precancerous and then cancerous. Cervical intraepithelial neoplasia (CIN) is the term used to describe these abnormal changes. CIN may progress to squamous intraepithelial lesion (SIL) a condition that precedes cervical cancer or to carcinoma in situ which can over time progress to invasive cancers. Other less common types of cervical cancer result from changes in the glandular surface cells (ademocarcinomas). Adenocarcinoma in situ (AIS) is a precursor of invasive cervical adenocarcinomas.1
In Europe the incidence of cervical cancer has decreased since the introduction of screening programmes around 9.84 deaths per 100,000 population (Northern Europe) and 10.18 per 100,000 population (Southern Europe) compared to sub-Sahara Africa with 25.08 to 44.32 deaths per 100,000 population.3
Infection with two types of human papilloma virus (HPV) which is transmitted sexually is strongly associated with the risk cervical cancer. HIV infection also reduces the immune system's ability to fight HPV infection. Sexual activity that increases risk for infection with HPV and HIV and for cervical cancer can include: having multiple sexual partners or a promiscuous partner, history of sexually transmitted disease, sexual intercourse at a young age and women who smoke, oral contraceptive use and giving birth to many children. It is commonly found in middle aged women and of women from poor socioeconomic status groups.1, 2
There are very few specific new treatments for cervical cancer which follows the traditional route of surgery, radiotherapy and chemotherapy. However if the cancer is caught early it is treated successfully. New treatments currently investigated include the tyrosine kinase inhibitors. 1
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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