The role of artificial intelligence in informed patient consent for radiotherapy treatments-a case report

Recent advancements in large language models (LMM; e.g., ChatGPT (OpenAI, San Francisco, California, USA)) have seen widespread use in various fields, including healthcare. This case study reports on the first use of LMM in a pretreatment discussion and in obtaining informed consent for a radiation oncology treatment. Further, the reproducibility of the replies by ChatGPT 3.5 was analyzed. A breast cancer patient, following legal consultation, engaged in a conversation with ChatGPT 3.5 regarding her radiotherapy treatment. The patient posed questions about side effects, prevention, activities, medications, and late effects. While some answers contained inaccuracies, responses closely resembled doctors' replies. In a final evaluation discussion, the patient, however, stated that she preferred the presence of a physician and expressed concerns about the source of the provided information. The reproducibility was tested in ten iterations. Future guidelines for using such models in radiation oncology should be driven by medical professionals. While artificial intelligence (AI) supports essential tasks, human interaction remains crucial.

Impact of Surgical Margins in Breast Cancer After Preoperative Systemic Chemotherapy on Local Recurrence and Survival

Background

While “no tumour on ink” is an accepted margin width for R₀ resection in primary surgery, it’s unclear if it’s oncologically safe after neoadjuvant chemotherapy (NAC). Only limited data demonstrate that surgery within new margins in cases of a pathological complete response (pCR) is safe. We therefore investigated the influence of different margins and pCR on local recurrence and survival rates after NAC.

Methods

We retrospectively analysed data of 406 women with invasive breast cancer, treated with NAC and breast-conserving therapy between 1994 and 2014 in two certified Austrian breast health centres. We compared R ≤ 1 mm, R > 1 mm and RX (pCR) for local recurrence-free survival (LRFS), disease-free survival (DFS) and overall survival (OS).

Results

After a median follow-up of 84.3 months, the 5-year LRFS (R ≤ 1 mm: 94.2%, R > 1 mm: 90.6%, RX: 95.0%; p = 0.940), the 5-year DFS (R ≤ 1 mm: 71.9%, R > 1 mm: 74.1%, RX: 87.2%; p = 0.245) and the 5-year OS (R ≤ 1 mm: 85.1%, R > 1 mm: 88.0%, RX: 96.4%; p = 0.236) did not differ significantly between narrow, wide, nor RX resections. Regarding DFS and OS, a negative nodal status reduced the hazard ratio significantly.

Conclusion

There is no significant difference in LRFS, DFS and OS comparing close, wide or unknown margins after pCR. We suggest that resection in new margins after NAC is safe according to “no tumour on ink”. Resection of the clipped area in cases of pCR is emphasized.

Abstract P5-16-06: Prepectoral versus retropectoral implant-based breast reconstruction - The surgical and radiotherapeutical perspective

Background: Subpectoral implant positioning has been the standard of care in breast reconstruction despite involving disadvantages owing to the detachment of the pectoralis major muscle such as disruption of the muscle function, animation deformities and prolonged postoperative pain. Refined ablative techniques as well as dermal matrices and synthetic mesh products have led to the reintroduction of subcutaneous implant-based breast reconstruction possibly avoiding the negative sequelae of pectoralis disinsertion.

Objective: The primary objective of this study was to compare procedure-related complication rates following prepectoral versus retropectoral implant-based breast reconstruction. Furthermore the effect of the implant position on the quality of post-mastectomy radiation therapy (PMRT) was analysed.

Methods: All patients who underwent an implant-based breast reconstruction after mastectomy at the Department of Obstetrics and Gynecology of the University Clinic of Vienna within the years 1.1.2013 to 31.12.2017 were included in the study. A retrospective chart review of the patients was conducted assessing parameters regarding the mastectomy, the reconstruction, complications following the reconstructive procedure, patient-associated risk factors and radiation treatment plans. Complication rates were analysed one week, one month and one year after the implant-based reconstructive operation.

Results: In total 57 patients (94 breasts) were reconstructed following a prepectoral implant-placement approach, 95 patients (149 breasts) were reconstructed with implants in a retropectoral position. The two patient cohorts did not differ significantly in the occurrence of complications including the following dehiscence, infection, seroma, secondary bleeding, necrosis, fistula, capsular contracture and rippling. No significant differences regarding reinterventions and reoperations including seroma drainage, secondary suture and reoperation following secondary hemorrhage and necrosis could be detected between the two study populations. The two surgical procedures were not associated with a different rate of implant loss.

12 (2 in the cohort of patients with prepectorally placed implants and 10 in the subgroup of patients with subpectorally positioned implants) out of 152 patients needed PMRT for oncological safety. Prepectoral versus retropectoral implant positioning did not affect breast Dmean or D90, heart Dmax or V5 or lung V20 across treatment plans.

Conclusion: The study demonstrated no inferior outcome regarding the occurrence of complications, reinterventions, reoperations and implant loss of prepectoral implant-based breast reconstruction compared to retropectoral implant positioning. Therefore, subcutaneous implant placement permits reconstruction of the breast with comparable procedure-related complication rates while avoiding disadvantages associated with the detachment of the pectoral muscle.

Regarding the radiation perspective both prepectoral and retropectoral implant positioning allow for optimal coverage of the chest wall with acceptable doses to the heart and lung.

Citation Format: Deutschmann C, Gschwantler-Kaulich D, Dorffner G, Singer C, Leser C, Kauer-Dorner D. Prepectoral versus retropectoral implant-based breast reconstruction - The surgical and radiotherapeutical perspective [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-16-06.