Characteristics of Chinese Families in Which Children and Both Parents Are Diagnosed with Malignant Tumors: A Retrospective Study.

Objective To characterize Chinese families in which both parents and at least one child are diagnosed with malignant diseases and provide reference for cancer screening or early detection in people whose both parents are diagnosed with cancer. Methods Medical records of all clients to the center of cancer screening and prevention of the National Cancer Center/Cancer Hospital between January 2008 and February 2018 were screened to select families in which both parents and at least one child were diagnosed with malignant diseases. The cancer profiles of fathers, mothers, sons and daughters, their age distribution at diagnosis, and similarity of cancers between two generations were analyzed. The proportions of each cancer in males and females of the cohort were compared with corresponding data from the National Cancer Center Registry of China (NCCRC) in 2013. Results Totally 135 families were identified from records of 33 200 clients. Proportion of lung cancer in fathers (40/135, 29.6%) and in mothers (38/135, 28.1%) were higher than the national data (23.9% in males and 14.9% in females, respectively). The proportion of breast cancer in daughters (35/109, 32.1%) was higher than that of mothers (14/135, 10.4%) and the national data (17.1%). In 71 father-son pairs of cancer, 46.5% (33/71) were of the same systematic disease, and 16.9% (12/71) were of the same cancer. These two indexes were 31.2% (n=34) and 10.1% (n=11), respectively in the 109 father-daughter pairs of cancer, 36.6% (n=26) and 8.5% (n=6) respectively in the 71 mother-son pairs of cancer, and 31.2% (n=34) and 20.2% (n=20) respectively in the 109 mother-daughter pairs of cancer. Sons were more likely to suffer from cancers originated from the same system as father's cancer than daughters (χ 2=4.299, P<0.05), and daughters were more likely to suffer from the same cancer as their mother's cancer than sons (χ 2=4.506, P<0.05). The age (mean ± standard deviation) of the daughters (52.4±12.7) and the sons (59.4±10.9) at diagnosis were significantly younger than the fathers (65.5±12.2) and the mothers (65.7 ±12.5) (all P<0.001). Conclusions For people whose both parents are diagnosed as cancer, screening or early detection examinations should cover a full range of cancers rather than the cancers their father and mother have suffered, or cancers stemmed from the same system as their parent's cancers. We suggest screening or early detection program for these special population start earlier than that for the general population, with emphasis on cancers derived from digestive system for males and women-specific cancers, i.e., breast cancer, ovarian cancer, cervical cancer and uterine cancer for females.