Inter- and intra-observer agreement on evaluating the presence of residual glandular tissue with magnetic resonance tomography following prophylactic mastectomy.

BACKGROUND: There are no published international consensus or guideline documents regarding appropriate medical follow-up for women with hereditary increased risk of breast cancer who opt for prophylactic mastectomy. Moreover, it is not known whether breast magnetic resonance imaging (MRI) performed after a prophylactic mastectomy is a reproducible method for evaluating whether clinically relevant amounts of residual glandular tissue remains. PURPOSE: To evaluate the inter- and intra-observer agreement on detecting residual glandular tissue with MRI. MATERIAL AND METHODS: In total, 40 women previously operated with prophylactic mastectomy underwent MRI and two breast radiologists (R1 and R2) independently assessed the presence of residual glandular tissue. Inter- and intra-rater agreements were assessed using Cohen's kappa (k). RESULTS: Residual glandular tissue was found in 69 of 248 quadrants (27.8%) and 32 of 62 breasts (51.6%) by R1 and 77 of 248 quadrants (31.1%) and 35 of 62 breasts (56.5%) by R2. The interrater agreement was observed to be moderate (k = 0.554) and the intra-rater agreement was observed to be substantial (k = 0.623). CONCLUSION: In conclusion, the inter-and intra-rater observer agreement in regard to detection of residual glandular tissue was not excellent, which would be desirable for a method considered reproducible enough to be used as a surveillance tool after the surgical procedure in order to ensure that there is no relevant residual glandular tissue remaining warranting further follow-up. More research is needed, as well as establishment of precise protocols, before using the method in risk assessment of remaining glandular tissue and breast cancer risk.

Mammography screening reduces rates of advanced and fatal breast cancers: Results in 549,091 women.

BACKGROUND: It is of paramount importance to evaluate the impact of participation in organized mammography service screening independently from changes in breast cancer treatment. This can be done by measuring the incidence of fatal breast cancer, which is based on the date of diagnosis and not on the date of death. METHODS: Among 549,091 women, covering approximately 30% of the Swedish screening-eligible population, the authors calculated the incidence rates of 2473 breast cancers that were fatal within 10 years after diagnosis and the incidence rates of 9737 advanced breast cancers. Data regarding each breast cancer diagnosis and the cause and date of death of each breast cancer case were gathered from national Swedish registries. Tumor characteristics were collected from regional cancer centers. Aggregated data concerning invitation and participation were provided by Sectra Medical Systems AB. Incidence rates were analyzed using Poisson regression. RESULTS: Women who participated in mammography screening had a statistically significant 41% reduction in their risk of dying of breast cancer within 10 years (relative risk, 0.59; 95% CI, 0.51-0.68 [P < .001]) and a 25% reduction in the rate of advanced breast cancers (relative risk, 0.75; 95% CI, 0.66-0.84 [P < .001]). CONCLUSIONS: Substantial reductions in the incidence rate of breast cancers that were fatal within 10 years after diagnosis and in the advanced breast cancer rate were found in this contemporaneous comparison of women participating versus those not participating in screening. These benefits appeared to be independent of recent changes in treatment regimens.

Prophylactic Mastectomy: Postoperative Skin Flap Thickness Evaluated by MRT, Ultrasound and Clinical Examination.

BACKGROUND: Women with an increased hereditary risk of breast cancer can undergo prophylactic mastectomy (PM), which provides a significant, but not total, risk reduction. There is an ongoing discussion about how much skin and subcutaneous tissue should be resected to perform an adequate PM while leaving viable skin flaps. METHODS: Forty-five women who had undergone PM were examined with magnetic resonance tomography (MRT), ultrasound (US) and clinical examination (CE) by a plastic surgeon and a general surgeon to estimate skin flap thickness. RESULTS: The estimated mean skin flap thickness after PM was 13.3 (± 9.6), 7.0 (± 3.3), 6.9 (± 2.8) and 7.4 (± 2.8) mm following MRT, US, and CE performed by a plastic surgeon and a general surgeon, respectively. The mean difference in estimated skin flap thickness was significant between MRT and the other measuring methods, while there was no significant difference between US and CE, nor between CE performed by the surgeons. The mean skin flap thickness was significantly affected by the age at PM. Following PM, necrosis was detected in 7/23 (30.4%) of the breasts in skin flaps ≤ 5 mm and in 5/46 (10.9%) of the breasts in skin flaps > 5 mm (OR 6.29; CI 1.20-32.94; p = 0.03). CONCLUSION: The odds of getting postoperative necrosis was > 6 times higher in skin flaps ≤ 5 mm. Thus, if the degree of remaining glandular tissue is acceptably low, it is desirable to create skin flaps thicker than 5 mm to prevent wound healing problems after the PM procedure.

Prophylactic mastectomy - Correlation between skin flap thickness and residual glandular tissue evaluated postoperatively by imaging.

BACKGROUND: Women with an increased hereditary risk of breast cancer can undergo risk-reducing prophylactic mastectomy. However, there is a balance between how much subcutaneous tissue should be resected to achieve maximal reduction of glandular tissue, while leaving viable skin flaps. METHODS: Forty-five women previously operated with prophylactic mastectomy underwent magnetic resonance tomography (MRT) and ultrasound (US) to investigate the correlation between skin flap thickness and residual glandular tissue. Residual glandular tissue was documented as being present or not present, but not quantified, as the amount of residual glandular tissue in many cases was considered too small to make reliable volume quantifications with available tools. Since a mastectomy skin flap thickness of 5 mm is discussed as an oncologically safe thickness in the literature, this was used as a cut-off. RESULTS: Following prophylactic mastectomy, residual glandular tissue was detected in 39.3% of all breasts and 27.9% of all the breast quadrants examined by MRT, and 44.1% of all breasts and 21.7% of all the breast quadrants examined by US. Residual glandular tissue was detected in 6.9% of the quadrants in skin flaps ≤ 5 mm and in 37.5% of the quadrants in skin flaps > 5 mm (OR 3.07; CI = 1.41-6.67; p = 0.005). Furthermore, residual glandular tissue increased significantly already when the skin flap thickness exceeded 7 mm. CONCLUSIONS: This study highlights that complete removal of glandular breast tissue during a mastectomy is difficult and suggests that this is an unattainable goal. We demonstrate that residual glandular tissue is significantly higher in skin flaps > 5 mm in comparison to skin flaps ≤ 5 mm, and that residual glandular tissue increases significantly already when the flap thickness exceeds 7 mm.

Early detection of breast cancer rectifies inequality of breast cancer outcomes.

OBJECTIVES: To explain apparent differences among mammography screening services in Sweden using individual data on participation in screening and with breast cancer-specific survival as an outcome. METHODS: We analysed breast cancer survival data from the Swedish Cancer Register on breast cancer cases from nine Swedish counties diagnosed in women eligible for screening. Data were available on 38,278 breast cancers diagnosed and 4312 breast cancer deaths. Survival to death from breast cancer was estimated using the Kaplan-Meier estimate, for all cases in each county, and separately for cases of women participating and not participating in their last invitation to screening. Formal statistical comparisons of survival were made using proportional hazards regression. RESULTS: All counties showed a reduction in the hazard of breast cancer death with participation in screening, but the reductions for individual counties varied substantially, ranging from 51% (95% confidence interval 46-55%) to 81% (95% confidence interval 74-85%). Survival rates in nonparticipating women ranged from 53% (95% confidence interval 40-65%) to 74% (95% confidence interval 72-77%), while the corresponding survival in women participating in screening varied from 80% (95% confidence interval 77-84%) to 86% (95% confidence interval 83-88%), a considerably narrower range. CONCLUSIONS: Differences among counties in the effect of screening on breast cancer outcomes were mainly due to variation in survival in women not participating in screening. Screening conferred similarly high survival rates in all counties. This indicates that the performance of screening services was similar across counties and that detection and treatment of breast cancer in early-stage reduces inequalities in breast cancer outcome.