In 2006, after collapsing at the airport, Reva Shayne Lewis was rushed to Cedar's and underwent some routine tests. The results brought her into the orbit of Dr. Colin McCabe, an oncologist. Colin explained to Reva that she needed to have surgery so that he could take a closer look at the mass in her breast and determine if it was cancerous. Rattled, Reva dismissed the good doctor. However, McCabe was not to be dismissed and bluntly pointed out that her health was her own responsibility and she'd shirked it by skipping out on mammograms. He abruptly announced that surgery was scheduled for the following morning. Afterwards, Colin was forced to tell her that the tumor was malignant. The next day, Colin kept calling Reva to discuss treatment. However, she was in denial about the seriousness of her condition and continually dismissed him. Finally, Colin announced if she wasn't going to follow his advice, he didn't want her as a patient. Put off by his bluntness, Reva went to see him. In serious denial, Reva asked Colin for a guarantee that radiation would work. Colin, obviously, couldn't give her one. Colin's direct approach irked Reva and blasted him on his lousy bedside manner. Colin tried another tactic by discussing her family but Reva informed him that she wasn't telling anybody--especially her husband. She stated that she refused to mar her husband, Josh's, happiness with this news. Although McCabe tried to argue that she was making a mistake, Reva refused to listen. The next day, Reva was shocked to learn that McCabe had rented the garage apartment at the Bauer home. When his new landlord, Rick, introduced Colin to Josh and Reva, Colin didn't let on that they'd met. Alone, Colin warned Reva she was in serious denial, and if she didn't get over it soon, she wouldn't be seeing him – or anyone – by the Bauer 4th of July BBQ.

Soon after, on Mother's Day, Reva finally decided to fight her cancer head on. However, she still refused to inform her family. Afterwards, Colin informed Reva he wanted to skip radiation and go straight to chemotherapy. After a few weeks of chemo, Reva noticed Colin's awkwardness around nurses. The irrepressible Reva decided that Colin needed to spice up his social life and pointed out that a certain pretty nurse liked him. Meanwhile, Reva's sister, Cassie, unexpectedly asked Colin out on a date. Colin, taking Reva's earlier words to heart, accepted. After the one date, Colin returned to focusing on his job, especially Reva. Time and time again, Colin insisted that Reva's family had to know about her condition but she stubbornly refused. Later, Colin was forced to give Reva bad news: her cancer was spreading. Colin informed Reva that there was an experimental treatment in Minnesota he wanted to try. In Minnesota, after one exciting day in which she lived out her dreams and almost forgot she had cancer, Reva went under the knife. Faced with the ever increasing knowledge that she might not have much time left, Reva decided she had to fulfill some of her dreams and asked Colin to help her. Though out of his element, Colin arranged for Reva to meet her idol at a celebrity show. When the show was canceled at the last minute, Colin impulsively stepped up and gave Reva a karaoke performance she would never forget. Later, he arranged for Reva to meet NASCAR driver Travis Kvapil who let her drive his #32 Tide/Downy Chevrolet Monte Carlo around the Hickory Motor Speedway.

The next day, Reva went in for the procedure. After it was completed, Reva told Colin she didn't understand him. When she asked how he got to where he was, Colin opened up about his sister, his best friend, who died of cancer at the age of 21. Colin admitted that he went to medical school a week later. He then revealed that for him being an oncologist was not about curing people; it was about getting revenge on the disease that took his sister away from him. When Reva showed a touch of vulnerability by admitting that she did not want to die, Colin responded that he wouldn't let her. Afterwards, Colin convinced Reva to attend a cancer survivor support group. Although she was reluctant, she agreed in exchange for him streaking in the hospital hallway. Though he balked, when Reva held up her end of the bargain, so did he. Later, when Reva got some promising test results, she and Colin went out to celebrate. After Reva arranged for Colin to have a date with a pretty nurse named Mandy, Reva lectured him about needing to be spontaneous. As she was talking, she was caught completely off guard when he spontaneously kissed her. Several days later, Colin had bad news: Reva needed to come back to the hospital because the test results are not good. They would have to do a stem cell transplant and she was going to need to be isolated since the slightest infection could kill her. Privately, Colin told Billy to put together a list of family members with contact information because if the procedure didn't work, there would have to be a bone marrow transplant. Reva was adamantly against it however, stating that she would not be a burden to her family. Reva's decision deeply upset Colin but she refused to budge.

Meanwhile, Billy continued to drag his feet about getting that list, even though time was of the essence. Finally, Billy informed Colin that he had himself tested in Springfield--he was a match for Reva. Though Colin wanted to run some tests, they were out of time. Unfortunately, while attempting to retract Billy's bone marrow, Colin noticed a problem and stopped the procedure. Later, he was forced to tell Billy that years of drinking had damaged his tissue. Luckily there was another option-Reva's son, Jonathan. Though Reva refused to allow the procedure since Jonathan had an adverse reaction to anesthetic, she relented when Colin informed her they could compensate for that. When Colin finished extracting the marrow, he informed Reva that she was free to go--they did all they could for her medically. A few weeks later, in Springfield, Colin was forced to deliver devastating news--her white cell count was lower than he thought it would be; she was losing her battle with cancer. Colin went on to explain that nothing more could be done; he didn't want to proceed with treatments that would lessen the quality of her life. When Reva started grasping at alternative treatments, Colin gently told that she was so full of life; he wanted her to be living it and not tilting at windmills. Reva needed to say her goodbyes now. Soon after, Colin drove Reva to the airport so she could visit her children. At the airport, Colin informed her that he was going back to Minnesota--where he could do the most good. When Reva thanked him for everything, he thanked her as well. She changed him; now when he treated people with kindness, he would have her to blame. Reva told Colin not to blame himself for her or his sister. He did everything he could.

Months later, in 2007, Colin returned to Springfield where Reva had made an amazing recovery. Apparently, the bone marrow transplant did work--her immune system was just so run down that it took a while. Colin remained close to his former patient and he was graced with a closely guarded secret--Jonathan had faked death in order to keep his daughter safe from Alan Spaulding. Before going off overseas on a medical mission for the government (where he would end up seeing Reva's other son, Shayne) Colin arranged for a visit with Jonathan, his daughter, and Reva. Unfortunately, Lizzie Spaulding followed Reva and Jonathan was forced to flee. Though Reva later begged Colin to call Jonathan back, he was forced to remind her that the risk was too great. He then paid adieu to Reva after promising to give Shayne a care package from her.