4/20/2021 E-Library - Information At Your Fingertips: Printer Friendly routinary.[104] We disagree. First, work-relatedness only demands a reasonable link between the illness and the seafarer's work. It does not require that the seafarer's work should be the main cause of the illness' progression. Justice Gesmundo posits that since Castillon's colon cancer could not have developed from Stage 1 to Stage 3 in a span of four (4) to six (6) months during which he was on board, his illness could not have developed due to his work.[105] However, work-relatedness does not mean that the illness drastically progressed due to the seafarer's work. There may be work-relatedness in cases where a seafarer's colon cancer developed from Stage 1 to Stage 3 during his employment and where a seafarer's cancer was in a more advanced stage at the time he or she was employed. The severity and progression of the illness is not the test of work-relation. As long as the work has "contributed to the establishment or, at the very least, aggravation of any pre-existing condition,"[106] work-relatedness is proven. Second, there is substantial evidence that Castillon's working condition contributed to or at least aggravated his illness. Castillon pointed out that the poor dietary provision as well as his continuous exposure to oils and fumes worsened his condition. This is consistent with jurisprudence where this Court has repeatedly recognized that high fat intake paired with an obnoxious working environment increases the risk of developing colon cancer. On the other hand, respondents never denied that this is the working condition of Castillon; they merely relied on the findings of the company-designated physician, which turned out to be incomplete and doubtful. Further, while Justice Gesmundo is correct in saying that there are various factors that lead to the development of the illness, all factors do not need to be entirely workrelated. As discussed in Leonis Navigation Co., Inc.,[107] family history, genetic predisposition, and the physical condition of the seafarer may likewise increase the risk of developing colon cancer. However, the lack of work-relation with these factors will not preclude compensability, because it is not required that the seafarer's work should be the sole contributor or factor in the aggravation of the illness.[108] It is sufficient that the seafarer's "employment contributed, even if only in a small degree, to the development of the disease."[109] To reiterate, only reasonable proof of work-connection is required, and not direct causation. In resolving compensability, this Court only looks for "[p]robability, not the ultimate degree of certainty."[110] Moreover, as pointed out, there is a disputable presumption of work-relatedness in cases of colon cancer; thus, the burden of proving otherwise is shouldered by respondents—a burden which they failed to discharge. Third, there is no contention as to the validity of the pre-employment medical examination. This type of initial examination is merely routinary and as such, the prehttps://elibrary.judiciary.gov.ph/thebookshelf/showdocsfriendly/1/66406 15/35