Mortality from breast cancer is more common among women with HIV

According to a cohort study presented Monday at the Conference on Retroviruses and Opportunistic Infections (CROI 2019) in Seattle, the mortality rate among HIV-positive women with breast cancer (BC) is higher than among those with a negative status.

The presence of HIV specialists is associated with a nearly twofold decrease in survival, which is confirmed by the findings of an assessment of breast cancer cases in a group of African women (Botswana) who received antiretroviral therapy (ARVT) and had an undetectable viral load, said conference participants Dr. Catherine Sadig from Hospital Brigham and Wimings and the Women's Hospital in Boston.

Because people living with HIV live longer because of effective antiretroviral treatment, AIDS mortality has decreased significantly, while non-communicable diseases, such as cancer and CVD, remain systemically important factors in the increase in the number of deaths. Breast cancer is considered the main cause of oncology death in women living with HIV who have access to effective antiretroviral therapy. A similar pattern is observed among HIV-negative women.

The Katherine Sadig team conducted a prospective analysis to assess the impact of HIV on the overall survival of women with breast cancer in under-resourced settings. While previous studies in the United States and Africa have shown that HIV-positive women do not have a higher incidence of breast cancer or the likelihood of developing cancer, some of the work with a small number of participants showed, on the contrary, that survival in the HIV + group may be reduced.

Specialists have studied the picture of the incidence of cancer among 4 thousand patients from four major cancer centers in Botswana. Participants were selected upon admission to the institution and studied for five years.

The cohort of breast cancer included 510 women who applied for cancer care in public or private clinics from October 2010 to September 2018. Of these, 151 were HIV positive.

The HIV + group was on average younger than HIV- (47 years old versus 56, respectively). In both groups, about 5% were admitted with stage I breast cancer, about 25% with stage II, about 40% with stage III, and about 15% with stage IV or metastatic cancer.

Both groups also had equal proportions of women with tumors positive for estrogen receptors (about 35%) and triple negative breast cancer, which did not respond to drugs traditionally used to treat it (about 15%).

According to Dr. Sadig, the Government of Botswana provided free treatment services for HIV and cancer. Since 2016, PLHIV in the country receive ARVT regardless of the number of CD4.

The majority of HIV-positive women (85%) took ARVT at the time of making a diagnosis of breast cancer, and three quarters did this for at least two years, and 70% had a viral load below 1000 copies / ml. The most common treatment regimens were zidovudine / lamivudine / efavirenz and tenofovir DF / emtricitabine / efavirenz.

Treatment of breast cancer in Botswana usually involves surgery with subsequent prophylactic (adjuvant) chemotherapy at an early stage of cancer or preoperative (neoadjuvant) chemotherapy followed by surgery or radiation therapy for patients with a later stage of the disease.

According to Dr. Sadig, both tamoxifen, a type of hormone therapy for breast cancer that is estrogen receptor positive, and Trastuzumab, are available in the country for treating HER2 positive tumors.

The types of treatment did not differ significantly depending on the HIV status: about 70% of women underwent mastectomy, about 60% underwent chemotherapy, and a little less than half underwent radiation therapy. Most received multimodal treatment.

During the study, 70 HIV-positive women (46%) and 101 who did not have the virus (31%) died. In both groups, breast cancer was the most common cause of death: it accounted for about 90% of cases; about 3% of deaths were associated with side effects during treatment. None of the women with HIV died directly from causes related to AIDS.

Thus, according to the multivariate analysis, the survival rate of HIV-positive women was 82% lower than among HIV-negative women.

The presence of HIV was associated with higher mortality in most subgroups. Minimal differences experts found among women with cancer stage IV, who had a high mortality rate, regardless of HIV status.

However, it was found that HIV has a greater effect on mortality among women in the early stage of breast cancer, which is negative for hormone receptors, and — unexpectedly — with a higher CD4 count (above 350 cells / mm3).

Experts can not yet explain this phenomenon.

"HIV infection was associated with a nearly twofold decrease in breast cancer survival, despite good access to ART, the study concluded, - Differences in the cancer stage, its subtype or access to treatment do not explain this imbalance."

Dr. Sadig noted that the mortality rate recorded by scientists in the course of the study showed extremely high results regardless of the patients' HIV status. This suggests that more effective strategies are needed for the diagnosis and treatment of breast cancer.