Incidence and decisions

A lot of medicine involves making decisions. Decision theory is informed by the probability of outcomes given specific information, and the costs associated with those outcomes.

Most people aren't good at probability (and nobody's really that good at it), but without some indication of probabilities, you can't be expected to make good decisions.

So. Given endometrial hyperplasia (thickening of the wall of the uterus) with no particularly visible tumors, how probable is cancer? I Google "incidence of carcinoma given endometrial hyperplasia" and find this: Incidence of endometrial carcinoma in patients with endometrial hyperplasia. (PubMed is our friend.)

Answer: 0.81%. Not a lot, but enough to take seriously. The abstract in full:

OBJECTIVE:

The purpose of this retrospective study was to establish the risk of developing endometrial adenocarcinoma in patients diagnosed with endometrial hyperplasia.

MATERIAL AND METHODS:

The incidence of endometrial hyperplasia and its relation with endometrial adenocarcinoma was evaluated in 1,139 patients who presented with abnormal bleeding between January 2000 and December 2004; D&C was performed in all cases. There were 591 (51.88%) cases of simple endometrial hyperplasia, out of which 110 (18.61% from 51.88%) cases had atypia, 60 (5.26%) cases of complex hyperplasia, out of which 19 (31.66% from 5.26%) had atypia, and the remaining 488 (42.84%) had different forms of mixed hyperplasia.

RESULTS:

The incidence of endometrial adenocarcinoma was 3.87% in atypical hyperplasia and 0.81% in other forms, and was related only to cases with atypia in which the incidence was 0.61%.

CONCLUSIONS:

The most indicated measure to prevent endometrial carcinoma in cases with complex endometria hyperplasia with atypia is hysterectomy, while for other forms of hyperplasia, hormonal treatment is used but only under strict control.

Not sure I agree with the conclusions, but I love those retrospective studies.

A summary of endometrial cancer

A great backgrounder on EC. Nothing stands out as particularly quotable; the whole thing is valuable.

Ultrasound of the uterus and endometrial hyperplasia

GE Healthcare has a fantastic rundown of ultrasound of the uterus (part of their ultrasound series, all of which is information-dense and informative), including sections on endometrial hyperplasia and carcinoma.

Quoting, first a brief summary of the endometrium itself:

Endometrium and Endometrial Cavity
As a review, the endometrium consists of two layers: functionalis, which is shed at the time of menstruation and the basalis, which restores the endometrium to prepare it for implantation. The phases of the endometrium start with menstruation. In this phase the coiled arteries constrict, reducing the supply of oxygen to the functionalis layer, shutting down the glands and the area becomes necrotic. The coiled arteries then rupture and bleeding ensues. On day 4 and 5, the basalis cells began to proliferate, to restore the epithelium for the next cycle. The proliferative phase correlates with days 4-14. In this phase the glands and connective tissue are regenerated by proliferation from the base. The functionalis has been fully restored by day 14, ending the follicular phase in a 28-day cycle. However, in longer cycles the proliferative phase is the one that is prolonged, so a 35-day cycle has a 20-21 day phase. Finally the secretory phase kicks in, which is the most constant phase in terms of time. In a 28-day cycle, the secretory phase starts on day 15 and lasts till day 28. A longer cycle can vary in the proliferative phase, delaying ovulation, however there is a constant lifetime for the corpus luteum.

...

Abnormal bleeding is one of the most common reasons a woman of any age seeks gynecologic health care. The most worrisome cause of abnormal bleeding is endometrial carcinoma, however benign etiologies are far more prevalent. These benign causes of bleeding can include fibroids, polyps and endometrial atrophy.⁷ Ultrasound along with Saline Infused Sonohysterography (SIS) can help in the diagnosis of these causes. Assessing the placement of an IUD (Figure 13) and endometrial abnormalities associated with Tamoxifen therapy are other areas where ultrasound can be helpful.

(I want to quote the salient parts in case of link decay; these resources are truly excellent and I don't want to find, five years from now, that they've moved on without leaving a forwarding address. Thus my policy for this entire blog will be to quote salient sections of text with proper attribution. Be warned.)

And the paragraphs on endometrial hyperplasia and endometrial carcinoma:

Endometrial Hyperplasia
Endometrial hyperplasia is a condition where the endometrium becomes overgrown, usually related to too much estrogen, or an imbalance between estrogen and progesterone. The most common symptom is abnormal bleeding. Endometrial hyperplasia is considered a benign condition, however development of adenocarcinoma is more likely if atypical cells are found on biopsy. Ultrasound cannot distinguish the different types of hyperplasia. In addition, the normal thickening of the endometrium that occurs in the secretory and late proliferative phases of the menstrual cycle cannot be distinguished from the diffuse thickening of endometrial hyperplasia. Sonohysterography in conjunction with transvaginal ultrasound enables accurate measurements of the endometrium. To help distinguish between normal and abnormal endometrial thickness, it is important to perform the sonohysterogram as early as possible after menstruation, ideally on days 4 to 6 of the menstrual cycle.

Endometrial Cancer
Endometrial cancer accounts for approximately 90 percent of uterine cancers. Adenocarcinoma, which originates in surface cells of the endometrium, accounts for most of the cases of endometrial cancer. Postmenopausal bleeding is the most common presenting symptom in women with endometrial carcinoma, but only 10% to 20% of women with postmenopausal bleeding will have cancer.⁹ Adenocarcinoma is often detected at an early stage because it frequently produces vaginal bleeding between menstrual periods or after menopause. If discovered early, this slow-growing cancer is likely to be confined to the uterus.

Endometrial cancer on ultrasound appears as diffuse thickening of the endometrium similar to hyperplasia, or as an inhomogeneous focal mass. Using a double-wall thickness of 5 mm or greater, the sensitivity for detecting endometrial cancer is 96% regardless of whether a woman is receiving hormone replacement therapy.

Patient's ultrasound results - reported, as sadly common in America, on the phone by a nurse instead of being faxed to the patient - are a thickening of the wall consistent with endometrial hyperplasia or carcinoma, followup testing indicated.

My general strategy for dealing with specialists is to get as many keywords as possible, then Google for results that are as definitive as possible. This isn't a surprise, of course - but it is surprising just how much informative material can (sometimes) be found. This is one of those cases. Thanks, GE, for doing it right!

Welcome to Blog #14

So, yeah, here's a place to put the various medical links I come across.

Our family of four has been hit by a really egregious number of medical panics: kidney disease, Crohn's Disease, possible cancer, and so on, and slowly we're learning how to understand these things on our own terms. "On our own terms" is kind of unique for us: my wife is a theoretical physicist, and I'm a programmer-turned-technical translator. We exemplify the engineering mindset, and we don't interact well with the medical establishment.

This is not to say we particularly care for woo-woo alternative medicine or "conspiracy-theory medicine" - but we do believe very fervently in dietary approaches, looking for root causes in our environment and lifestyle, and above all, preserving quality of life in all things. Living with your body means you have to treat it right, and sometimes you don't realize that until things are really seriously wrong. That doesn't mean you have to - or even should - delegate the decisionmaking to your doctor. Everything you do is your decision, although you can expect a great deal of friction if you take that attitude.

I don't expect to devote a lot of time to this blog in the foreseeable future, but when we have a crisis, I end up doing a lot of research that tends to get lost. For now, this blog will be my effort to keep that loss to a minimum.

The current crisis: endometrial hyperplasia and the possibility of endometrial carcinoma, patient aged 45.