IT’S ALWAYS SOMETHING <i> by Gilda Radner (Simon & Schuster: $17.95; 269 pp.) </i>

“Portrait of the Artist as a Housewife” is the title Gilda Radner initially intended for this book, which she had envisioned as “a collection of stories . . . about things like my toaster oven.” Fate dealt her a considerably less humorous topic, however, in late 1986, when she was diagnosed with ovarian cancer.

One might think Radner among the least well-equipped to grapple with such a demon in print, for the comedienne’s best-known characters on the original “Saturday Night Live”--little girls at slumber parties or on first dates--seemed to spring from a still-innocent spirit. Radner’s style of comedy, however, like that of her colleagues on the show, was precisely the kind that drew its inspiration from inner pain. John Belushi, for example, Radner’s mentor and best friend on the show, might have seemed to practice only diverting slapstick--throwing himself in the air and splashing on the hard set in one skit, threatening to stab himself in another--but his work had a manic attribute that seemed driven by necessity, as if living life on the edge was a way of palliating inner fears. Similarly, Radner’s characters, as she recounts here, often were drawn from turbulent childhood memories.

Because Radner’s comedy had this serious, introspective side, the spirit of honesty and bravery that is so apparent in these pages comes as no surprise. This is not to imply, however, that Radner wasn’t devastated by the diagnosis, for it came two years after she had married actor Gene Wilder, giving up her self-destructive behavior (such as chain-smoking) to begin a new, domestic life: Around Wilder, Radner writes, “The brash and feisty comedienne turned into this shy, demure ingenue with knocking knees.”

First on Radner’s new agenda was to bear a child, but when she found she couldn’t sustain a pregnancy, she began the regimen of tests and operations that the majority of this book chronicles, often with great humor: “I saw the dye running through my reproductive system on a closed circuit screen in the examining room,” she writes. “There I was, lying on a table with my legs spread apart, watching the worst show I’d ever seen on television. The show was called, ‘My Tubes Were Closed.’ ”

These pages are not always so lighthearted, though, for as Radner’s title suggests, “It’s Always Something” is essentially a collection of bittersweet stories about living with what her therapist calls life’s “delicious ambiguity.” It is about “not knowing, having to change, taking the moment and making the best of it.” One day in the midst of her chemotherapy treatments, for instance, Radner puts on a raincoat and goes walking on the street. A car comes by and splashes her with mud: “That’s me,” she says loudly to herself, “‘Cancer Woman’! You can do anything to me. I can walk through storms. I can get splashed by cars. I can have millions of treatments. You can radiate me, you can give me poisons, but you can’t destroy me because I’m Cancer Woman!”