quarta-feira, 20 de janeiro de 2016

Can We Truly "Cure" Cancer?

In one well-known episode of The West Wing a line about an astronomical effort to “cure cancer” gets cut from the president’s State of the Union. In real life, however, someone wrote the speech that the fictional president Josiah Bartlet never got to give.
On January 12 Pres. Barack Obama laid out an aspirational plan in his final State of the Union to “cure cancer.” He did not put forth a specific time line for this effort or the metrics that would measure success but did say that he was putting Vice Pres. Joe Biden in charge of “mission control.” And already, the White House released information aboutseveral meetings in the coming month that Biden will hold to get the ball rolling on the initiative.
Yet is such a goal truly achievable in the near future? Patients and doctors know all too well that cancer is not one disease and there is no singular cure for the complex group of disorders. Biden did help secure a $264-million cash infusion in the most recent government spending bill that will support cancer work at the National Cancer Institute, but the obstacles to attacking cancer effectively are more than just financial. “A cure is a long way off,” but the prospect for some specific cancers does look bright, says James Allison, chair of the Department of Immunology at The University of Texas M. D. Anderson Cancer Center in Houston. For his part, at least Allison was not surprised about the announcement last night, he says, because the vice president himself called him and other researchers within the past two months to talk about cancer research. And now, unlike even five years ago, a 10-year remission is realistic for cancers like melanoma, which seemingly were unbeatable.
These gains are largely thanks to historic breakthroughs in the past few years with a bevvy of methods to employ patients’ own immune systems, collectively known as immunotherapy. But still large obstacles remain when it comes to getting immunotherapy to work for many different types of tumors. Although some cancers—particularly those that are rife with mutations like lung cancer or melanoma—create more tangible targets on the surface of cells for the immune system to recognize and attack, other malignancies such as prostate and pancreatic cancers have proved more intransigent. As Scientific American reported earlier this year, more than half of the current cancer clinical trials do incorporate some form of immunotherapy but still oncologists are often only in the early stages of understanding how to use such treatment on a larger scale. Even with the cancers that are further along in their immunotherapy responses, a “certain fraction of those kinds of tumors, I don’t know we’ll ever cure,” Allison says.
Monica Bertagnolli, chief of the Division of Surgical Oncology at Brigham and Women’s Hospital and chair of the Alliance for Clinical Trials in Oncology, a nationwide effort to test new therapies, says she was thrilled that the president used the word “cure” in his speech at all. “I don’t think any of us are naive and think there is some magic bullet sitting under our thumb that is going to miraculously turn into a cure, but that’s where we have to aim—to cure,” she says. “For that reason, I think it was perfect to use that terminology.” Like Allison, Bertagnolli believes cures will be difficult to achieve and questions if that will be possible for some cancers. But the next best thing, she says, is “making sure that it [cancer] doesn’t negatively impact a patient’s life” and laying out this aspirational goal may help provide the impetus to get there and beyond.
Still, even agreeing on the definition of “cure” remains controversial. Cancer is often talked about in terms of years in remission rather than cure because there is still the creeping concern that the cancer will one day resurface. But whereas some “old school surgeons” would see potentially suspicious dark scar tissue on a CT (computed tomography) scan and say you cannot say cancer is “cured,” Allison maintains if there is no real evidence that a person still has cancer and they have been in remission for 10 years, “for all intents and purposes it is cured.”
Clinicians’ recent gains against cancer are not just due to immunotherapies. The American Cancer Society’s recent annual report on cancer indicates that more than 1.7 million cancer deaths have been averted between 1991 and 2012 largely due to better preventative steps such as smoking cessation and screening for breast  and colon cancers.
Despite the progress against cancer, however, it is still the number-two killer in the U.S. after heart disease. Although more people are living or living longer with cancer than in years past, that is still not truly curing cancer. Cancer will certainly remain part of the human condition but the question is how best to tamp it down when it does appear. One of the biggest challenges that remains is making sure therapies continue to work with patients in the long term and pinpointing if that means cancer therapies should be administered in combination or deployed in a specific order for certain patients. “Unfortunately, we see some patients don’t respond to these wonderfully new therapies and some patients that do respond initially eventually develop resistance to those therapies and so the tumor returns,” Bertagnolli says. “Obviously that’s in the way of curing cancer because we want a treatment that a patient will never develop resistance to.”
Indeed, the fight against cancer is a long one and the president only has one year left in office. In the 1970s Pres. Richard Nixon called for a “War on Cancer.” That effort, alongside its public relations campaign, fueled unrealistic expectations that cancer would be quickly extinguished. So what’s different here? For one thing, the base level of knowledge about cancers and their causes—and targets to combat them—is fundamentally different. “I hope people don’t think the cure is right around the corner but I do think there’s reason for optimism,” Allison says. “To use a Texas term, we finally have purchase on it.”

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