In situ breast cancer surgeries in Sweden: lumpectomy or mastectomy?-a cost-effectiveness analysis over a 30-Year period using Markov model.

Background: Breast cancer represents the most prevalent cancer among Swedish women. Although considerable research has investigated the cost-effectiveness of emerging innovative medical treatments for breast cancer, studies addressing existing surgical procedures remain scant. Therefore, this study aimed to evaluate the cost-effectiveness of three surgical procedures for in situ breast cancer treatment in Sweden: mastectomy, lumpectomy without irradiation, and lumpectomy with irradiation.

Methods: A six-state Markov model with a 30-year time horizon was used to compare the cost-effectiveness of the three alternatives. Transition probabilities were based on a targeted literature review focusing on available evidence in Sweden and comparable contexts. Costs were estimated from both healthcare and societal perspectives, using patient data from the Swedish National Cancer Registry in 2020 (Cancerregistret). Health outcomes were quantified in terms of quality-adjusted life years (QALYs). Cost and health outcomes were then summarised into an incremental cost-effectiveness ratio (ICER) between competing strategies. A probabilistic sensitivity analysis (PSA) was conducted to address the uncertainties in the input parameters.

Results: The results showed that compared to lumpectomy without irradiation, lumpectomy with irradiation yielded a "moderate" ICER per QALY gained of 402,994 Swedish Krona (SEK) from a healthcare perspective and a "high" ICER of 575,833 SEK from a societal perspective. Mastectomy proved to be the costliest and least effective of the three alternatives over a 30-year period. The PSA results further substantiated these findings.

Conclusions: Our study demonstrated that lumpectomy with irradiation is "moderately" cost-effective compared with lumpectomy without irradiation. Nevertheless, extending this study by conducting a comprehensive budget impact analysis to account for the prevalence of in situ breast cancer in Sweden is prudent. These results imply that a costlier and less effective mastectomy should only be considered when lumpectomy options are infeasible. Further studies are needed to obtain more reliable parameters relevant to Sweden and to increase the consistency of the findings.