Abstract P4-07-03: The impact of HIV on non-adherence for tamoxifen among women with breast cancer in South Africa
Bibliographic record
Abstract
Abstract Introduction HIV-positive women with breast cancer (BC) have worse overall survival than HIV-negative women with BC, and poor adherence to prescribed tamoxifen is known to contribute to poor survival. We, therefore, investigated the association of HIV infection with adherence to adjuvant tamoxifen among women with localized hormone receptor (HR)-positive breast cancer in South Africa. Methods Among 4,097 women diagnosed with breast cancer at six hospitals in the prospective South African Breast Cancer and HIV Outcomes (SABCHO) cohort study between July 2015 and December 2020, we focused on women with stages I-III HR-positive breast cancer who were prescribed 20mg of adjuvant tamoxifen daily for ≥3 months during the study period. We collected venous blood once from each participant during a routine clinic visit and analyzed concentrations of tamoxifen and its metabolites using a triple quadruple mass spectrometer. We defined non-adherence as a tamoxifen level < 60ng/mL after 3 months of prescribed daily tamoxifen use. We compared socio-demographic, lifestyle factors, tamoxifen-related side effects, and concurrent medication use among women with and without HIV and developed multivariable logistic regression models of tamoxifen non-adherence. Results Among 369 participants, 78 (21.1%) were HIV-positive and 291 (78.9%) HIV-negative. After a median (interquartile range) time of 13.0 (6.2-25.2) months since tamoxifen initiation, the tamoxifen serum concentration ranged between 1.54 and 943.0ng/mL, with a median of 52.3ng/mL. In the full cohort, 208 women (56.4%) were non-adherent to tamoxifen; only 161 (43.6%) were adherent. Women < 40 years of age were less likely to adhere to tamoxifen than women >60 years (73.4% vs 52.6%, odds ratio (OR)=2.49, 95% confidence interval (CI)=1.26-4.94); likewise, HIV-positive women (70.5% vs 52.6%, OR=2.16, 95% CI=1.26-3.70) were less likely to adhere than HIV-negative women. In an adjusted model, only HIV was associated with non-adherence; HIV-positive women had twice the odds of non-adherence to tamoxifen, compared to HIV-negative women (OR=2.40, 95% CI=1.11-5.20). Conclusion Non-adherence to tamoxifen may limit the overall survival of women with HR-positive breast cancer; in our study, especially in HIV-positive women. Citation Format: Oluwatosin A Ayeni, Shingirai Chiwambutsa, Wenlong Carl Chen, Nyasha N. Kapungu, Comfort Kanji, Roslyn Thelingwani, Nivashni Murugan, Rophiwa Mathiba, Boitumelo Phakathi, Sarah Nietz, Duvern Ramiah, Daniel S. O’Neil, Judith S. Jacobson, Paul Ruff, Herbert Cubasch, Tobias Chirwa, Maureen Joffe, Collen Masimirembwa, Alfred I. Neugut. The impact of HIV on non-adherence for tamoxifen among women with breast cancer in South Africa [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-07-03.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".