Uterine cancer

Japanese: 子宮癌 - しきゅうがん（英語表記）uterine cancer

It is a cancer that originates in the uterus, and is the second most common organ cancer in women after stomach cancer. It is divided into cervical cancer and uterine cancer depending on the site of onset, but the two are treated as completely different cancers because they are all different in terms of predisposition, histological structure, symptoms, progression, treatment, and prognosis. However, in Japan, more than 80% of uterine cancers are cervical cancer, and uterine cancer often refers to cervical cancer. In addition, both types of cancer are always classified according to the degree of progression according to the International Convention (conventions adopted by the International Commission on Cancer of Gynecology and Obstetrics in 1961) before treatment. Regardless of the treatment given, the prognosis is greatly influenced by the clinical stage classification of the patient at the time treatment begins, and the more advanced the stage, the worse the prognosis becomes.

[Masao Arai]

Cervical cancer

It develops from the mucous membrane of the cervix, and the most important area for its development is the area near the external cervical os, that is, the boundary between the multi-layered squamous epithelium that covers the vagina and the single layer of columnar epithelium that covers the cervical canal. It is most common in people in their 40s and 50s, but in the very early stages it is often discovered in people in their 30s during mass screenings, and can also be seen in people in their 20s. Therefore, regular cervical cancer screening should be done once you are over 30 years old.

Cervical cancer is divided into five stages, from stage 0 (zero) to stage IV, depending on the extent of its progression. There are almost no symptoms in stage 0 or the beginning of stage I, so it is called preclinical cancer. The initial symptom is at most a small amount of bleeding after sexual intercourse (contact bleeding). As the cancer gradually infiltrates, bleeding becomes easier, and in addition to frequent bleeding after sexual intercourse, bleeding also becomes more likely when defecating or urinating. There may also be dirty vaginal discharge. In such cases, regardless of age, it is important to see a doctor immediately. In stage III, the cancer reaches the pelvic wall and puts pressure on the nerves, causing neuralgia. Swelling (edema) may also be seen in the lower limbs and lower abdomen.

[Masao Arai]

diagnosis

This is done by combining the following three methods.

(1) Cytology: The contents of the vagina and the area around the cervix are scraped and smeared onto a glass plate, stained, and examined under a microscope to determine the presence or absence of cancer cells and the extent of their progression. This is an essential test for early detection, and there is also a method in which women can collect vaginal contents themselves, smear them on a glass plate, and send it to a laboratory.

(2) Colposcopy: This is a procedure in which the area around the cervix is observed using a colposcope (a magnifying glass), and areas where cancer is particularly likely to develop are photographed and recorded in diagrams. It is also called a colposcopy for short.

(3) Histological examination: This is done when abnormal findings or cancer are suspected in cytology or colposcopy. A special resection instrument is used to extract a portion of the tissue from the suspected area, and a tissue specimen is prepared and examined under a microscope. A definitive diagnosis of uterine cancer is made by histological examination.

[Masao Arai]

Treatment

The main treatments are surgery and radiation therapy, with chemotherapy and immunotherapy sometimes used. In stage 0, the clinical stage of progression, 100% cure can be expected with a vaginal conization or a total hysterectomy. In stages I and II, radical surgery or radiation therapy is performed, while in stages III and IV, radiation therapy is the main treatment, with surgery or a combination of surgery and radiation therapy sometimes used, and chemotherapy is also used in cases of systemic metastasis.

[Masao Arai]

Uterine cancer

It is more prevalent among Caucasians, and among those prone to obesity and diabetes, high blood pressure and infertility. It is uncommon among young women, but the incidence has been increasing in recent years.

The menstrual flow may continue for a long time or irregular bleeding may occur occasionally, and detailed examination is required for irregular menstruation during menopause or bleeding after menopause. Diagnosis requires cytological examination of secretions from the uterine cavity and histological examination by curettage.

In clinical staging, like cervical cancer, it is classified from stage 0 to stage IV, but there are some differences in the details, with stage I being concerned with the size of the uterus and the pathological tissue appearance. As the majority of corpus cancers are adenocarcinomas with low sensitivity to radiation, surgery is the preferred treatment. Simple total mastectomy is often appropriate, and the cure rate is generally better than for cervical cancer. In recent years, large doses of synthetic progesterone hormone (gestagen) have also been shown to be effective as hormone therapy.

[Masao Arai]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

Japanese:

子宮に原発する癌で、女性では臓器癌のうち胃癌に次いで多い。発生部位によって子宮頸(けい)癌と子宮体癌に分けられるが、両者はまったく別の癌として扱われているほど、発生素因や組織学的構造、症候や進展状況、治療や予後などもすべて異なる。しかしまた、日本では子宮癌の80％以上が子宮頸癌であり、子宮癌といえば子宮頸癌をさす場合が多い。なお、両者とも治療に先だって進行の程度を国際規約（1961年、国際産婦人科学会癌委員会採択の規約）によって決められた臨床進行期分類に従ってかならず分類される。予後はいかなる治療が行われたにしても、治療が開始されたときの患者の臨床進行期分類に大きく左右され、その段階が進むほど不良となってくる。

［新井正夫］

子宮頸癌

子宮頸部の粘膜から発生し、とくに外子宮口付近、すなわち腟(ちつ)部を覆う多層の扁平(へんぺい)上皮と頸管部を覆う1層の円柱上皮との境界部が、発生上もっとも重要な部分とされる。40歳から50歳代に多いが、ごく初期の段階では集団検診などで30歳代に発見される率が高く、20歳代にもみられることがある。したがって子宮癌の定期検診は、30歳を過ぎれば受けるべきである。

　子宮頸癌は、進行程度によって0(ゼロ)期からⅣ期までの5段階に分けられる。0期やⅠ期の初めころにはほとんど症状がなく、臨床前癌とよばれているほどである。初発症状としては、せいぜい性交後に少量の出血（接触出血）をみる程度である。しだいに癌の浸潤が進むと出血しやすくなり、性交後にたびたび出血するほか、排便や排尿時にも出血しやすくなる。また、汚れた「おりもの」がある。このようなときには、年齢を問わず、即刻診察を受ける必要がある。Ⅲ期では癌が骨盤壁に及んで神経を圧迫し、神経痛がおこる。また、下肢や下腹部にむくみ（浮腫(ふしゅ)）がみられる。

［新井正夫］

診断

次の三つを組み合わせて行う。

(1)細胞診　腟の内容や子宮口付近を擦過してガラス板に塗抹し、染色して顕微鏡で癌細胞の有無や進行の程度を判定する。早期発見に欠かせない検査法で、女性が自分で腟内容を採取してガラス板に塗り、検査所に送る方法もある。

(2)コルポスコープ診　コルポスコープ（腟拡大鏡）で子宮口周辺全般を観察し、とくに癌が発生しやすい部位を撮影したり模式図で記録するもので、コルポ診とも略称される。

(3)組織診　細胞診やコルポ診で異常所見や癌が疑われたときに行われ、特殊な切除器で疑いのある部位の組織の一部を採取し、組織標本をつくって顕微鏡で調べる。子宮癌の確定診断は組織診によって決定される。

［新井正夫］

治療

治療法としては手術と放射線療法が主であり、場合によって化学療法や免疫療法なども行われる。臨床進行期の0期では、腟部円錐(えんすい)切除ないしは子宮単純全摘除術で100％治癒が期待できる。Ⅰ期およびⅡ期では根治手術か放射線療法が行われ、Ⅲ期とⅣ期の場合は主として放射線療法、場合によっては手術、あるいは手術と放射線療法の併用、全身転移例には化学療法も行われる。

［新井正夫］

子宮体癌

白色人種に多く、肥満および糖尿の傾向のある人、高血圧や不妊の人などに多くて若い女性には少ないが、近年増えつつある。

　月経に似た出血が長く続いたり不正出血がときどきみられ、とくに閉経期の月経不順や閉経後の出血は精密検査が必要である。診断には、子宮腔内の分泌物を吸引して細胞診を行うとともに、診査掻爬(そうは)による組織診を必要とする。

　臨床進行期分類では子宮頸癌と同様に0期からⅣ期まで分類されるが、細部の点で異なり、Ⅰ期では子宮の大きさや病理組織像が問題にされる。治療としては、体癌の大部分が放射線感受性の低い腺(せん)癌であるため手術が優先される。単純全摘出術の適応例が多く、治癒率も一般に頸癌より良好である。近年はまた、ホルモン療法として合成黄体ホルモン（ゲスタゲン）の大量投与が有効とされている。

［新井正夫］

出典　小学館　日本大百科全書(ニッポニカ)日本大百科全書(ニッポニカ)について　情報 | 凡例

<<: Uterine fibroids

>>: Extra Uterine Pregnancy