Objective: To estimate the risk of incident cancer; any type and specific types‎ in PD (Parkinson’s disease) patients, by sex; and to compare it to the risk in the general population; In a large-scale cohort study.

Background: PD patients were shown to have a differential risk of different type of cancers. Data on this association may improve the understanding of the etiology and pathogenesis of PD.

Methods: Using BIG-DATA approach: The PD population-based retrospective cohort included 7125 new patients, for the period 1.1.2000 to ‎‎31.12.2012 (study period); based on drugs purchases database of Maccabi Health ‎Services (MHS). Information on incident cancer during this period was derived from MHS cancer registry‎. We used K-M curves to estimate time to cancer event. Standardized Incidence Ratios (SIRs) accounting for age, chronological year and sex were calculated to compare incident cancers among PDs to that of MHS population.

Results: The PD cohort included 54% men, with mean age of first treatment 71.2 years (sd=10.3), in a time-window of 7 years before first treatment and 3.5 years after that: 21% men and 15% women were diagnosed with incident cancer.

Table 1- Characteristics of the PD cohort

	Men (n=3828)	Women (n=3297)
Age at 1st APD purchase(mean ± SD)	71.1 ± 10.6	71.5 ± 10.7
Follow-up time (yrs) (mean ± SD)	10.4 ± 3.5	10.9 ± 3.2
Person years	43710	38190
Time (yrs) before 1st APD purchase (mean ± SD)	6.67 ± 3.6	6.40 ± 3.6
Time (yrs) after 1st APD purchase (years ± SD)	3.69 ± 4.0	4.49 ± 3.8
Incident Cancer comorbidity (%)	21.0	15.1
Comorbidities except for cancer
CHF (%)	12.4	9.7
MI (%)	8.5	7.2
Stroke (%)	16.3	11.7
TIA (%)	5.9	4.3
Atrial fibrillation (%)	15.6	13.2
HTN (%)	40.1	47.2
Deceased (%)	36.0	31.2

APD- anti Parkinsonian drugs; CHF- congestive heart failure; MI- myocardial infarction; TIA- transient ischemic attack; HTN- hypertension. For any type of cancer – we found no difference in the risk of the PDs compared to the reference population, in both sexes. Significant decreased risks in the PD cohort were found for lung and colon cancers. For other cancers: breast, CNS, kidney, leukemia, lymphoma, melanoma, ovary, pancreas, prostate, rectum and, thyroid, there was non-significant differences in the risks of PDs compared to the reference population. SIRs did not differ significantly between the sexes. Men with PD had a higher risk of cancer of all types combined than women with PD, but when accounting for sex- differences in cancer risk in the reference population, those differences disappeared.

Table 2 – Standardized incidence ratios (SIR) comparing the PD cohort with MHS population for any cancer and for specific types of cancer

Cancer type (ICD-9)	Males		Females
	N	SIR (95% CI)	N	SIR (95% CI)
Any type (140-239)	804	0.99 (0.92-1.06)	498	0.98 (0.89-1.07)
Breast (174-175)			127	1.15 (0.95-1.36)
Colon (153)	43	0.53 (0.42-0.78)	27	0.58 (0.35-0.77)
CNS (191-192)	4	0.77 (0.21-1.97)	2	0.45 (0.05-1.61)
Kidney (189)	23	1.06 (0.67-1.59)	5	0.56 (0.18-1.32)
Leukemia (204-208)	14	0.7 (0.38-1.18)	9	0.89 (0.41-1.70)
Lung (162)	19	0.35 (0.21-0.54)	11	0.52 (0.26-0.94)
Lymphoma (200-202)	31	1.03 (0.70-1.46)	16	0.74 (0.42-1.20)
Melanoma (172)	25	0.92 (0.60-1.36)	19	1.08 (0.65-1.69)
Ovary (183)			5	0.46 (0.15-1.08)
Pancreas (157)	2	0.15 (0.02-0.54)	11	0.85 (0.42-1.52)
Prostate (185)	200	0.99 (0.86-1.14)
Rectum (154)	15	1.06 (0.68-1.56)	11	0.77 (0.39-1.38)
Thyroid (193)	7	1.59 (0.64-3.27)	8	0.93 (0.40-1.84)

PD: Parkinson’s disease; MHS: Maccabi Health Services; CNS: central nervous system.

Conclusions: Our big-data analysis found no difference in the risk of any-type of cancer among PDs compared to the general population in contrast to some previous findings, but we focused in a certain time-window. Specifically, lung cancer and colon lower risks findings are in line with previous studies. The non-increased breast cancer and melanoma risks findings somewhat differ from previous studies. More large-scale data linkage studies are needed to explore cancer comorbidity among PDs in different time windows to shed more light on this association.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/cancer-comorbidity-among-pd-patients-a-population-based-large-scale-cohort-study/