Identifying radiation-induced survivorship syndromes affecting bowel health in a cohort of gynecological cancer survivors.
BACKGROUND
During radiotherapy unwanted radiation to normal tissue surrounding the tumor triggers survivorship diseases; we lack a nosology for radiation-induced survivorship diseases that decrease bowel health and we do not know which symptoms are related to which diseases.


METHODS
Gynecological-cancer survivors were followed-up two to 15 years after having undergone radiotherapy; they reported in a postal questionnaire the frequency of 28 different symptoms related to bowel health. Population-based controls gave the same information. With a modified factor analysis, we determined the optimal number of factors, factor loadings for each symptom, factor-specific factor-loading cutoffs and factor scores.


RESULTS
Altogether data from 623 survivors and 344 population-based controls were analyzed. Six factors best explain the correlation structure of the symptoms; for five of these a statistically significant difference (P< 0.001, Mann-Whitney U test) was found between survivors and controls concerning factor score quantiles. Taken together these five factors explain 42 percent of the variance of the symptoms. We interpreted these five factors as radiation-induced syndromes that may reflect distinct survivorship diseases. We obtained the following frequencies, defined as survivors having a factor loading above the 95 percent percentile of the controls, urgency syndrome (190 of 623, 30 percent), leakage syndrome (164 of 623, 26 percent), excessive gas discharge (93 of 623, 15 percent), excessive mucus discharge (102 of 623, 16 percent) and blood discharge (63 of 623, 10 percent).


CONCLUSIONS
Late effects of radiotherapy include five syndromes affecting bowel health; studying them and identifying the underlying survivorship diseases, instead of the approximately 30 long-term symptoms they produce, will simplify the search for prevention, alleviation and elimination.
Division of Clinical Cancer Epidemiology, Department of Oncology, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.|Department of Oncology and Pathology, Division of Clinical Cancer Epidemiology, Karolinska Institutet, Stockholm, Sweden.
Gunnar
G
Steineck
Division of Clinical Cancer Epidemiology, Department of Oncology, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
Viktor
V
Skokic
Division of Clinical Cancer Epidemiology, Department of Oncology, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
Fei
http://orcid.org/0000-0002-8305-7648
F
Sjöberg
Division of Clinical Cancer Epidemiology, Department of Oncology, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
Cecilia
C
Bull
Division of Clinical Cancer Epidemiology, Department of Oncology, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
Eleftheria
E
Alevronta
Institute of caring Sciences, Ersta Sköndal University College, Stockholm, Sweden.
Gail
G
Dunberger
Division of Clinical Cancer Epidemiology, Department of Oncology, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
Karin
K
Bergmark
Division of Clinical Cancer Epidemiology, Department of Oncology, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
Ulrica
U
Wilderäng
Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, United States of America.
Jung Hun
JH
Oh
Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, United States of America.
Joseph O
JO
Deasy
Chalmers University of Technology, Gothenburg, Sweden.
Rebecka
R
Jörnsten
D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005833:Genital Neoplasms, Female / Q000532:radiotherapy* / Q000601:surgery; D006801:Humans; D008875:Middle Aged; D011788:Quality of Life; D011832:Radiation Injuries / Q000175:diagnosis*; D011878:Radiotherapy / Q000009:adverse effects*; D011795:Surveys and Questionnaires