Abstract PS7-85: Population based survival of breast cancer in Greater Mumbai, India

Abstract

Abstract Introduction: Population based survival provides a measure of the efficacy of cancer control in a defined geographical area. The Mumbai Cancer Registry (MCR), India’s oldest population based cancer registry (PBCR), was established by the Indian Cancer Society (ICS) in 1963. It covers 603 sq. km. of Greater Mumbai with a population of 146, 51,584 (2015) and over half a century it has consistently provided cancer statistics from its coverage area. Breast cancer is the commonest cancer in women in Mumbai constituting 30% of all female cancers, and is now the most common cancer in women in India (1, 62,468 in 2018), constituting 27.66% of all female cancers. There have been few reports on breast cancer survival from India, and in this study, we report the survival rate of women diagnosed with breast cancer in Greater Mumbai during the years 2009-13. Patients and Methods: Breast cancer cases registered during the years 2009-13 with the MCR were followed for outcome till 31 Dec 2018. Social investigators visited hospitals, nursing homes, clinics, hospices and laboratory centers for documenting cancer cases. Mortality data was collected from the Vital Statistics Division of the Municipal Corporation. Data and was verified and duplicate cases were deleted. Follow up was conducted with repeated scrutiny of medical records, death certificates issued by the Municipal Corporation, postal and telephone enquiries, house visits and linkage with electoral database. Observed survival was calculated by the Kaplan Meir (1958) method. Expected survival was calculated using the national life-table of India for (Maharashtra) based on Census of India, 2011. Using observed and expected survival, relative survival was calculated by Ederer (1961) method using STATA 12.0. The survival rate was compared to that from other regions of India and with developed countries. Results: Of the 9707 breast cancer cases registered during the period 2009-13, 8031 (83%) cases were included in this study. 1676 (17%) cases were excluded as 469 (5%) had only Death Certificate Information and 1207 (12%) were lost to follow up. The median follow up was 5.1 years (range 8 months - 9 years). The median age was 55 years (range 18 -96 years) with 2725(34%) ≤ 50 years and 5306 (66%) > 50 years. The overall observed survival rates at 1, 3, 5 years were 82.5%, 72.8% and 67.0% respectively and the corresponding figures for relative survival were 83.5%, 75.4%, and 70.9%. Increasing age had an inverse relationship with breast cancer survival. The highest 5-year relative survival was shown by ≤29 age group (74%) and lowest by >70 age group (60%). Those with localised disease at diagnosis had a higher 5-year relative survival rate (84%) compared to 79.7% for direct extension and 20.8% for distant metastasis. The clinical extent of disease and education were significant risk factors affecting survival (p < 0.001). Conclusion:The 5-year population-based survival of patients treated in Greater Mumbai during the period 2009-2013, is 70%. This compares favourably with previously reported 5-year survival from Mumbai (51-55.7%) and other Indian registry data (33-55%), but is inferior to that reported in the developed world (84-88 %). The association of survival with educational status and stage at diagnosis highlights the importance of awareness and early detection. Enhanced awareness and detection coupled with easy access to adequate and affordable treatment could help improve breast cancer outcomes. Citation Format: Vinay Deshmane, Shravani Koyande, Shweta Jadhav. Population based survival of breast cancer in Greater Mumbai, India [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS7-85.