It said the region "has been largely neglected in global cancer control" and continues to face "tremendous challenges in providing adequate cancer prevention and control services".
In a statement, lead author Professor Diana Sarfati said: "many Pacific Island countries and territories either lack or have poorly developed cancer screening, pathology, oncology, surgical and palliative care services".
"Added to this, access to morphine is very limited, so death can often be excruciating," Professor Sarfati said.
Professor Diana Sarfati
Death can often be excruciating
The report found a lack of cancer screening and diagnostic services meant many patients often tend to seek medical attention "only when their cancers are at an advanced stage".
And Professor Sarfati said some patients are simply "not receiving care at all".
Geographic challenges were described in the report as a major barrier to cancer care.
Researchers cited Tokelau as one such example, as it "does not have an airport or port, and all off-island travel must go via Samoa, a 24+ hour boat journey available fortnightly".
While in Papua New Guinea, "rugged mountainous terrain, swamplands, and large rivers make over half the country inaccessible by road", meaning cancer care is inaccessible for many.
According to the report, about 16,200 new cancer cases and 9,800 cancer deaths are reported in Pacific Island nations annually.
As a result of population growth and ageing, Pacific Island states could be dealing with between 20,000 and 45,000 additional cancer cases and between 12,000 and 28,000 additional deaths a year by 2040.
Pacific health ministers are this week gathering to discuss health challenges in French Polynesia's Pape'ete, with Australia's Health Minister Greg Hunt joining them on Tuesday.