Aug. 1, 2012 -- Arijit Guha, an Arizona State University graduate student, returned from a trip to India with a stomach ache and only one month later learned he had Stage IV colon cancer.

As tough as his diagnosis was at the age of 30, learning that his insurance company would place restrictions on paying for his cancer treatments was almost as gut-wrenching.

Guha had a policy under the university's health plan for which he paid $400 a month out of pocket, but its carrier, Aetna, had an annual ceiling on pay-outs. After surgery and chemotherapy, he had exhausted the lifetime $300,000 limit.

The Affordable Healthcare Act has eliminated lifetime limits, but until Aug. 1 that did not include student health plans, according to the Chronicle of Higher Education.

Outraged, Guha turned to Twitter and other social media to make his case, one that affects millions of Americans who face staggering medical bills.

But last week, Aetna CEO Mark T. Bertolini, a former paramedic who has had his own share of medical crises, tweeted directly with Guha and agreed to pay "every last penny" of his bills.

"The system is broken, and I am committed to fixing it," said Bertolini on his Twitter account, according to the Arizona Republic, which first covered the story. "I am glad we connected today and got this issue solved. I appreciate the dialogue no matter how pointed. I've got it and own it!"

Guha, now 31, told ABCNews.com, "I am incredibly pleased and in shell shock and trying to figure out what just happened. It's a huge relief."

It turns out Bertolini and Guha have much in common.

In 2001, Bertolini's then 16-year-old son son, Eric, was diagnosed with a rare and deadly lymphoma, according to a profile in the Hartford Courant. And in 2004, when he was president of Cigna, Bertolini was disabled after being nearly killed in a ski accident. He also eventually donated a kidney to help save his son.

Bertolini admitted the current healthcare system was "broke" and tweeted, "There is a lot to do to make it right."

Meanwhile, Guha had raised $120,000 through T-shirt sales in his edgy campaign "Poop Strong," which riffs on cancer survivor Lance Armstrong's "Live Strong." And now that Aetna has stepped in, Guha said he will donate all of it to three cancer charities in Arizona.

Guha continues to fund raise for cancer support and research on his blog, "Stage IV Hope."

Colorectal cancer is the second leading cancer killer in the United States, according to the Centers for Disease Control and Prevention. In 2008, the last year for which there are statistics, 142,950 Americans were diagnosed with colorectal cancer and 52,857 Americans died from the disease.

Surprisingly, colorectal cancer is not that uncommon among younger people like Guha, especially those who have a family history of early-onset disease.

"It's not shocking at all," said Dr. Joel Levine, founding director of the Colon Cancer Prevention Program at the University of Connecticut.

There are three risk zones for the disease, according to Levine. About 70 percent of all cases are sporadic; 20 percent come from a familial risk; and 2 to 3 percent result from a gene mutation that passes from generation to generation.

Doctors should take a detailed three-generation family history so that risk for a young person isn't "underestimated," he said. Genetic studies can reveal specific inherited syndromes that can cause colon cancer, allowing other family members to more closely monitor their health.

"If we get all the details correct, picking up the histories for inheritable risk, we can reduce the probability of developing colon cancer," said Levine.

Colon Cancer Symptoms Should Not Be Ignored

Symptoms can include rectal bleeding or anemia, abdominal pain or occult blood in the stool.

Such was the case with Guha, who was diagnosed in February 2011. He had settled in Phoenix with his wife and was getting a doctorate in environmental sustainability. The couple returned from a trip to India to visit his relatives and Guha developed abdominal pain.

"It seemed like the standard sort of bug issue when I get back from India," he said. "But it continued and got different, to the point where I was doubled up on the floor, and I was having trouble eating."

Because of his age, doctors never suspected cancer and looked at every other possibility, "including the plague," said Guha. A battery of tests were negative, but eventually a colonoscopy revealed a 6 cm.-wide tumor in the sigmoid colon.

When he saw a report that suggested it was malignant, Guha said, "I was in denial ? I thought surely there was another explanation."

MRIs and surgery revealed that the cancer had proliferated into his entire abdominal cavity -- a stage 4 diagnosis.

"It was pretty dire," he said. "But one of the things that makes it so deadly, is you have these metastases to distant organs like the liver, lung and brain and people usually die from organ failure."

But in Guha's case, the spread of cancer was confined to the abdominal cavity, a rare progression that doctors told him made the disease more treatable.

He had a colostomy, conventional chemotherapy, the removal of his gall bladder and a heated chemo bath of the lining of his stomach -- as the medical bills mounted.

By the time Guha had exhausted his insurance benefits, he had about $118,000 in medical bills. But now, future treatments will be covered under his student insurance plan.

"I take it day by day," said Guha, who was on a road trip to Idaho to serve as officiant at a friend's wedding. "It's quite likely that I'll have chemo again if [the cancer] pops up again. But I feel really good and I'm looking good."

So far, doctors say tests to determine if his early-onset cancer was genetic are all negative.

These cases of early-onset colon cancer that occur only in an individual and not in a family are a "rare event, not quite a black swan," said cancer expert Levine.

Guha is reassured that other family members may not suffer the same fate and also that his unusual case is hopeful.

"In the midst of what seems pretty scary, this is all working in my favor," he said. "I am younger and can handle the treatment better. The average age of a colon cancer patient is 71.4. My guess is most of those people are probably overweight and have comorbidities."

Just recently, doctors found one tiny spot of cancer on his liver, but a minimally invasive procedure called radio frequency ablation was able to kill it.

"It's not as if I think about the worst case scenarios all the time or I have the specter of death looming over me," he said.

"I could never get through life like that or be a productive member of society," said Guha. "I have always dedicated my life to doing something useful."

These days, he has dedicated himself to fundraising for more support for cancer patients and their families, especially Arizona's undocumented, who have no insurance.

Aetna spokesman Cynthia B. Michener said the insurance company would cover Guha's costs through the end of the plan year. His school's student plan just raised its annual limit to $1 million, and the new Affordable Health Care Act has eliminated lifetime limits, she said.

"While we are pleased to have found a solution for our member, we recognize that there is much more work to be done to fix the problems in our health care system," said Michener in a prepared statement. "We are committed to reforms that make the system work better for everyone."

Those who would like to learn more about Guha's charities can go to the University of Arizona Cancer Center's Patient Assistance Fund, the Colon Cancer Alliance or Wellness Community Arizona.