Until Monday the worst thing facing me this week was a root canal.

And then my sister Tris, my personal idol, died.

There is nothing I can write that would do justice to her, but she is at the top of my mind and I can't seem to wrestle with any other subject today. It feels self-indulgent, but I hope you'll understand.

It was cancer that did Tris in. As best I can understand it, the disease started in her thyroid and made its silent march, invading the rest of her body before her doctors realized what was going on.

Last spring, as soon as she was diagnosed with a cancerous tumor, my sister and her husband Frank traveled from their home in Clovis to UCLA, where she met with a highly-regarded surgeon who was upbeat about her prognosis. The operation to remove the tumor was scheduled for the next day. Frank and Tris spent that night at our house. She went over with us everything the surgeon told her, reassuring us that the situation looked quite hopeful. And, as she sat on our den couch watching one of the final episodes of "Lost," she fielded cell phone calls from her concerned adult children. "I'll be just fine," she told them.

Because they planned to leave the house long before we woke up the next morning, Tris and I hugged each other before saying goodnight. Had I known it was the last hug I would ever receive from her, I would have held on for dear life.

Initially, the outlook was good. But once the surgeon discovered how invasive the cancer had become, all bets were off. Within a short time after she returned home she was told she had stage 4 lung cancer. The fight was on.

Per our agreement, she would call me whenever she felt up to talking. That amounted to fewer than a half-dozen calls over the past six months or so. I understood completely and gave her the space she requested. Things seemed to be looking up a couple of weeks ago, when she felt strong enough to drive her car to do errands. In fact, she mailed me a hilarious birthday card then. The last time we spoke she sounded chipper, and I felt hopeful that we would have her in our lives for years to come.

The four of us siblings have always been a humorous bunch. But Tris was especially sly in her humor, the corners of her lips barely curling upward as she softly uttered a zinger that would set everyone at the dinner table into fits of laughter. She stood out from the rest of us in other ways, too. She was not only the most attractive member of our extended family, hands down, but she also had a quiet reserve, a personal dignity none of the rest of us has mastered.

She was also our head cheerleader. We were capable of succeeding at anything we tried, at least in her eyes. Seven years her junior, I leaned heavily on her for advice throughout my formative years — and beyond — and she never let me down.

Our brother Larry, the eldest of the bunch, often groused, only somewhat jokingly, that Mom had played a cruel joke on him by providing him with three sisters and no brothers. Tris's untimely death this week seems to have softened his take. He sent this one-line e-mail message to me and our other sister, Sharon, Tuesday night, under the subject line "reflection."

"For so long it seemed like I had too many sisters, and now, not so much."

CAROL CORMACI is managing editor of the Valley Sun. E-mail her at ccormaci@valleysun.net or carol.cormaci@latimes.com.