Effect of screening by clinical breast examination on breast cancer incidence and mortality after 20 years: prospective, cluster randomised controlled trial in Mumbai

Abstract

Objective To test the efficacy of screening by clinical breast examination in downstaging breast cancer at diagnosis and in reducing mortality from the disease, when compared with no screening. Design Prospective, cluster randomised controlled trial. Setting 20 geographically distinct clusters located in Mumbai, India, randomly allocated to 10 screening and 10 control clusters; total trial duration was 20 years (recruitment began in May 1998; database locked in March 2019 for analysis). Participants 151 538 women aged 35-64 with no history of breast cancer. Interventions Women in the screening arm (n=75 360) received four screening rounds of clinical breast examination (conducted by trained female primary health workers) and cancer awareness every two years, followed by five rounds of active surveillance every two years. Women in the control arm (n=76 178) received one round of cancer awareness followed by eight rounds of active surveillance every two years. Main outcome measures Downstaging of breast cancer at diagnosis and reduction in mortality from breast cancer. Results Breast cancer was detected at an earlier age in the screening group than in the control group (age 55.18 (standard deviation 9.10) v 56.50 (9.10); P=0.01), with a significant reduction in the proportion of women with stage III or IV disease (37% (n=220) v 47% (n=271), P=0.001). A non-significant 15% reduction in breast cancer mortality was observed in the screening arm versus control arm in the overall study population (age 35-64; 20.82 deaths per 100 000 person years (95% confidence interval 18.25 to 23.97) v 24.62 (21.71 to 28.04); rate ratio 0.85 (95% confidence interval 0.71 to 1.01); P=0.07). However, a post hoc subset analysis showed nearly 30% relative reduction in breast cancer mortality in women aged 50 and older (24.62 (20.62 to 29.76) v 34.68 (27.54 to 44.37); 0.71 (0.54 to 0.94); P=0.02), but no significant reduction in women younger than 50 (19.53 (17.24 to 22.29) v 21.03 (18.97 to 23.44); 0.93 (0.79 to 1.09); P=0.37). A 5% reduction in all cause mortality was seen in the screening arm versus the control arm, but it was not statistically significant (rate ratio 0.95 (95% confidence interval 0.81 to 1.10); P=0.49). Conclusions These results indicate that clinical breast examination conducted every two years by primary health workers significantly downstaged breast cancer at diagnosis and led to a non-significant 15% reduction in breast cancer mortality overall (but a significant reduction of nearly 30% in mortality in women aged ≥50). No significant reduction in mortality was seen in women younger than 50 years. Clinical breast examination should be considered for breast cancer screening in low and middle income countries. Trial registration Clinical Trials Registry of India CTRI/2010/091/001205; ClinicalTrials.gov NCT00632047 .

The Global, Regional, and National Burden and Trends of Breast Cancer From 1990 to 2019: Results From the Global Burden of Disease Study 2019

“…Therefore, clinical breast examination should be considered for breast cancer screening. A recent trial in Mumbai found that clinical breast examination conducted every two years significantly downstaged breast cancer at diagnosis and also led to a significant reduction of nearly 30% in mortality in females aged ≥50 (27). What's more, we found that low-middle and low SDI experienced higher age-standardized DALYs.…”

Locally Advanced Breast Cancer—A Narrative Review of Management in the Indian Scenario

“…58 This is further reiterated by the hot-off-the-printing-press results of a large, 20-year-long RCT conducted in Mumbai, India, which demonstrated a 30% significant reduction in BC mortality in women aged more than 50 years when screened 2 yearly by CBE by trained primary health workers. 59 Early detection would strengthen clinicians with more conservative options of treatments in their armamentarium, so that patients may be offered conservative modalities of surgical intervention such as sentinel lymph node biopsy, BCT, etc., therefore, reducing costs toward treating morbidity incurred among the treated population and improving quality of life (QOL). Detecting BC in the early stages may also help save costs on prevented palliative care.…”

Breast Cancer Early Detection in Eswatini: Evaluation of a Training Curriculum and Patient Receipt of Recommended Follow-Up Care

“… 9 - 16 Recent data from India suggest that CBE screening decreases BC stage at diagnosis and may decrease BC mortality in women > 50 years old. 17 However, there is consensus that before any screening program can be implemented, health systems must have the capacity to facilitate early diagnosis of symptomatic disease by building community awareness, enhancing providers' ability to evaluate abnormal findings, and ensuring robust referral systems to facilitate timely diagnosis. 18 In Rwanda, Pace et al developed a BC early-diagnosis program that trained nurses from primary health centers to address breast complaints and to perform CBE.…”