The consultant breast surgeon’s name is Mr Al-Dubaisi, and he sees me Monday evening at the private hospital, The Garden Clinic, around the corner from where I’ve lived most of my life. I like him as soon as I walk in. I crack some joke and he laughs. Later I can’t remember what was funny, but I remember it was a genuine, throaty chuckle he gave.

He asks a couple of questions, like when did you first find the lump, looking up from his sheet of white paper when I say, “Uh, quite a long time ago, probably when I was pregnant, actually.” “How old’s the baby?” he asks pleasantly. “Three in a couple of months,” I answer. He glances up, considering this, before moving on. Later, when I say, I should have come earlier, shouldn’t I, childlike, seeking dispensation, he offers it instantly. “We don’t talk about what’s already happened, no, no, no, it’s closed.” His delivery is clipped, precise, like Hercule Poirot, whom he resembles.

Then he says, “I have to ask you something, and you must answer me very, very honestly, Dina.” Oh no, I freeze. Here it comes. I know what this is, how will I deal with it? He’s going to ask me if, as a Jew, I mind that he’s an Arab. “Dina,” gently prods this soft, courteous man. “If it becomes necessary, would it be very inconvenient for you to come and see me at my clinic in Bushey?”

Mr Al-Dubaisi calls in a chaperone before he gives me a physical examination. He sends me to undress, just the top half, behind curtains in the corner of the room. I can hear him, pacing the room, edgy. I feel that he is concerned not to give me a second’s extra anxiety, to diagnose a benign lump as soon as possible. The instant the nurse comes through the door, he bursts back through the curtain.

Then he stops, still. “I can see it,” he says, straightaway. “It’s large.” His face, which is a warm, beige colour, looks momentarily grey. This is not feigned. He doesn’t know me at all, this man, but he cares this much.

People have different reactions when you tell them you have breast cancer, and it depends what generation they are from. You see, for the ones like me, late 30s, early 40s, it’s just beginning to dawn on us that we’re the target group now. The sixth series of Sex and The City was built round Samantha’s breast cancer. Samantha’s hair came out in her boyfriend’s fist while they made love, and he lost his erection. Samantha raged at the doctor who told her it was her sex-loaded, pregnancy-free existence that was to blame. “I’m going to find a woman doctor,” she yelled, “who knows what she’s talking about.”

For children the same age as mine - teenaged and younger - it’s an illness they are also newly hearing about; it just wasn’t part of our lives when we were their age. They know that Anastasia, the pop star, had breast cancer a couple of years back, and has only just returned to performing. For them it means coming to terms with the fact that for about a year of their lives, their mothers will be ill. “I don’t want you to change, mum,” my 10-year-old says. “I don’t want you to be tired; I don’t want you to lose your hair,” she adds, fiercely.

But for our parents’ generation, hearing about our breast cancer, it’s a death knell before our time.

It’s an illness older women expect to happen to them, if anyone. Breast cancer screening is given to the over-50s, routinely. But now breast cancer figures are running at one in nine women, highest rates in the Netherlands and the US; lowest in Haiti and the Gambia. The UK has the 13th-highest incidence.

“But Dina, you read. How could you not know?” asks my mother’s old friend, sitting down, hard, on the bench in our hallway.

So here’s what I knew. LSE and University of East Anglia-educated, consumer of two broadsheets a day. I knew, and so was able to tell my Cambridge-top-of-his-year, multiple books-a-day husband, with quite impatient certainty, that women like me, who had their first children in their 20s and what’s more - this was the clincher - breast-fed those babies for well over a year each, women like me don’t get breast cancer.

Fact: having children before the age of 20 or even 30 is protective against breast cancer.

Fact: the longer the period of breast-feed ing, the lower the risk of breast cancer for the mother. (New England Journal of Medicine, 1993, and Chris J, Women who Breastfeed. American Health, April 1994.)

“But it’s growing bigger,” my husband Anthony says, one night. “And it’s so hard.” “I know,” I answer, “I’ll make the appointment.”

I go to the GP on a Friday afternoon when my older children spend the weekend with their father. I am still breastfeeding my child. At almost three, more shocking than cancer in this society.

A lump, I tell the GP. She feels it, tentatively. “You need to be seen by a specialist. Within the next few days. Do you have private insurance? Make an appointment with whoever is available first.” On the NHS, she says, I would be seen within two weeks.

I have a sense that when something is serious it’s safer to be in NHS hands - the Royal Free, a huge teaching hospital, is our local. No, says the GP, get diagnosed.

Anthony is in Cambridge for his eldest son’s graduation; my three girls, 15, 14, and 10, at their father’s. So it’s me, the baby and the breast with what now feels like a rectangular slab of metal embedded inside. When I first found it, long ago in a bath one night, it was small and pea-shaped. This too-quiet afternoon at home is not, after all, a good time to have made the GP appointment. Our huge, airy house, that we were so lucky to find, with space for eight kids, their music and us, now feels like it’s folding in on me.

I phone Elly. Apart from her five children, she has 38 people for Friday-night dinner in two hours. Twenty minutes later she’s at my door with two takeaway coffees and her own home-made cookies. A tricky recipe, soft chocolate insides, dusted with icing sugar. My mother used to make these same chocolate crinkles, as they’re called, and I often experiment, always trying to get them to taste right.

Over the weekend, my two-year-old feeds as usual. My appointment with the breast cancer consultant is fixed for Monday evening.

“I’m tapering off,” I’ve told our scornful teenage brood, whose current mantra is, “Do you know how embarrassing this is going to be for him when he’s 10? Do you realise he’s starting school soon?”

When I was pregnant, my step-daughter, opened the topic at supper one evening. “Dina,” she said, “you’re not going to do that thing, are you?” What thing? I asked. “You know, thingy in EastEnders tried it, that feeding of babies in public thing.” “Not in public, mum,” my then 12-year-old, chimed in, very firm.

“Oh right,” I said. “Cos babies should have to wait when they’re hungry, like you all do.”

But when he arrived, all these children loved that baby so much, they forgave him anything. Even the frequent public breastfeeding.

Seven-thirty pm and I am Mr Al-Dubaisi’s last patient on a day that began at 8am with his NHS clinic, followed by meetings with other breast-cancer specialists and ending at this small hospital in north-west London.

Before touching my breasts, he studies them. He asks me to lift each arm separately over my head. Then he tells me to put my hands on my hips and press in, a procedure which is requested by each of the breast-cancer specialists I will see. Finally, he asks me to lie down and lift my arms over my head, and he feels the breasts for the first time, also prodding under my arms.

He turns away to let me get dressed, and the “chaperone nurse” leaves the room, smiling goodbye. Back at his desk, Mr Al-Dubaisi says he’s sending me for a mammogram, a scan and probably a biopsy. “Yes, certainly, a biopsy.” “What, tonight?” I say. “Yes, yes, of course, tonight. Is your husband coming?” Anthony stayed home to tuck our child up, and he will come when our babysitter arrives.

I don’t know what a mammogram is, I’ve had scans when pregnant, but I don’t know what a biopsy is. I’m surprised that it’s all happening this same evening. A mammogram is an x-ray, he explains, and a biopsy, he says, means putting a needle in. “Very, very fine,” he says.

“I don’t usually wait, but I will stay tonight to talk to you afterwards. For you,” he says. His voice is soft. It sounds to me like his way of letting me know it’s serious.

I’m muddled. My older children won’t be home from their father until tomorrow. On Friday I had told the children I was going to see our GP, unusual enough for me, because, I guess, part of me knew this was a “real” lump, while at the same time having only the sketchiest sense of breast cancer. When your children live in two homes, one of the things that needs attention is that crucial stuff doesn’t happen behind their back. In the throes of divorce, I learned the key to guiding children through hard times is making sure you don’t hide the bad things from them.

But this is all moving faster than I’d anticipated.

It’s 10pm when I walk through my front door. My right breast is punctured now, and bandaged, then covered with waterproof plastic pressing down the nipple. I’ve added four Nurofens to the local anaesthetic.

• Dina Rabinovitch’s column will be appearing fortnightly from next Tuesday

• 18 March 2021: this article has been edited to remove some personal information.