亞東紀念醫院教學研究 副院長 葉坤輝醫師

前言

癌症自民國七十一年起一直高居國人十大死因首位，國人無不談癌色變。以醫療保健的觀點來看，如何預防癌症、早期發現、早期治療、與多學科化整合治療、癌症疼痛控制，均是癌症診療系統中的重要課題。其中「預防」癌症的發生更是有效降低癌症，減少癌症對國人身心健康、家庭、社會、與醫療經濟等危害的最主要關鍵。

防癌有若干重要的原則，民眾不但需要了解，而且可以身體力行。吾人提供以下要訣作為防癌的重要原則。首先，應從飲食習慣與生活習慣的改善著手。

要訣一：減少動物性脂肪的攝取 ，專家建議將脂肪的攝取降低至總熱量的 30% 以下，甚至 20% ，如此可以降低攝護腺癌、結腸癌或乳癌的罹患率。

要訣二：多攝取高纖食物與蔬果 ，已證實可以降低結腸直腸癌與乳癌的罹患率，也有助於降低消化系統癌症與其他荷爾蒙敏感癌症的發生，建議每天至少攝取 20~30 克纖維量，與 5~8 份蔬果。

要訣三：充分的運動與維持標準體重 ，身體活動不足易導致冠狀動脈心臟病、糖尿病與結腸癌，體重過重與乳癌、子宮內膜癌等有關，增加身體活動性可降低結腸癌的危險約 40~50% ，建議 ” 每週至少 ” 消耗 1,500 大卡 ( 或 150 分鐘 ) 於休閒運動。

要訣四：避免食物／飲水／空氣中的致癌物質 ，避免 發霉 的玉米、花生等，以防止麴菌毒素的危害，其中著名的 ” 黃麴毒素 ” 與肝癌的發生有關；飲用含砷的井水，易導致膀胱癌；此外，高蛋白食物加上 燒烤、油炸、煙燻 的處理程序，易產生異環芳香氨與多環芳香烴等致癌物，與肺癌、肝癌、結腸癌、乳癌、皮膚癌、口腔癌、攝護腺癌有關；而 鹽醃、醃漬 的食物，則因亞硝胺的形成，與消化道癌症、鼻咽癌、膀胱癌、肝癌有關；其他工作職場與空氣污染也有許多的潛在危害物質存在，應學習如何有效防護。

要訣五：攝取飲食中的天然抗癌物質 ，雖然可能僅含微量於天然飲食中，但因長期食用，且多種綜合攝取，仍是重要的防癌方式。其中有幾類重要的抗癌物質， （１）類胡蘿葡素 ，如蕃茄紅素，富含於蕃茄中，長期攝取量與攝護腺癌、胃癌、肺癌的罹患率成反比； （２）植物雌激素 ，富含於黃豆與高纖穀物為主的食物中，可降低乳癌，攝護腺癌的罹患率； （３）有機硫（烯丙基化硫） 富含於蒜頭、青花椰菜、高麗菜中，可降低胃癌的罹患率，而 有機硒 可降低攝護腺癌， （４）各種酚化合物：藜蘆醇 ，富含於葡萄、紅酒、花生根中，可抑制乳癌、皮膚癌； 單酚 ：富含於漿果（藍莓）、堅果（胡桃、核桃）中，可抑制肺癌、食道癌； 類黃酮 ：可抑制卵巢癌、乳癌、胃癌、口腔癌； （５）茶多酚化合物 ：綠茶中的兒茶酚 EGCG ，可預防肺癌、食道癌、胃癌、皮膚癌等，紅茶中亦含防癌有用的茶黃素。 （６）異硫氫酸鹽與靛基質 ，富含於十字花科蔬菜，如花椰菜、青花椰菜等，可抑制肺癌、乳癌、食道癌等。

要訣六：保持愉快輕鬆的心情 。慢性的精神壓力，易影響體內神經與免疫系統，降低免疫細胞的數目與功能，使免疫防衛系統變差，甚至增加癌症轉移。

要訣七：避免致癌的行為 ： 不抽煙、拒吸二手煙 ，可減少肺癌、口腔癌、咽喉癌、食道癌、胃癌、胰臟癌、腎臟癌、膀胱癌等； 不嚼檳榔 ，可減少口腔癌、食道癌； 不過量飲酒 ，可減少食道癌、肝癌等； 安全的性生活 ，避免多重性伴侶，可防止病毒的感染，減少子宮頸癌與卡波西肉瘤等； 避免過量的陽光照射 ，減少皮膚癌，

要訣八：疫苗預防與化學預防 ，民國七十三年開始，Ｂ型肝炎疫苗接種是舉世聞名的肝癌預防計劃，已有效降低疫苗計劃開始後出生的下一代之肝癌發生率；此外，許多研究嘗試於癌症的化學預防，譬如：維生素Ａ衍生物可使約 60%-80% 之「口腔白斑」癌前病變回復正常，亦可有效降低第二原發性癌約 50 ％；長期服用貝他－胡蘿葡素，維生素Ｅ與硒，有效降低胃癌死亡率。此外，服用非類固醇抗炎製劑 (NSAIDs) ，可有效抑制 FAP 「家族性腺瘤多發性息肉症候群」患者之結腸腺瘤性息肉數目。但這些化學預防策略仍在持續研發階段。

相信了解這些防癌要訣之後，不但存乎於心且務必身體力行，才能有效地「預防癌症」與降低癌症的發生率。

未來，我們將進一步介紹癌症的早期症狀與各種癌前病變，以提醒民眾提高警覺，並介紹各種癌症的高危險群，以推廣高危險群病患定期癌症篩檢的重要性，以達到「早期診斷、早期治療」的目的。

此外，我們亦將持續宣達目前癌症治療學的最近進展與新觀念，目前結合多學科的整合性癌症團隊，與未來結合癌症診療服務、研究、教學的整合型癌症中心，將在亞東紀念醫院展現癌症治療全新風貌。  

 

What is Cervical Cancer?

Cervical cancer develops when abnormal cells located in the lining of the cervix begin to grow out of control and invade other parts of the body – a process called metastasis . The cervix is the part of the womb that connects the vagina, the birth canal and the upper part of the uterus, where fetuses grow. These changes in the cells are referred to by several terms, including dysplasia. For some women, these changes may go away without any treatment. More often, they need to be treated to keep them from changing into true cancers.

Abnormal cervical cells can localize to form a lump called a tumor. Benign tumors do not spread and are usually not harmful. Malignant tumors, however, spread from their sources and can grow into life-threatening cancers.

Types of Cervical Cancer

There are two main types of cancer of the cervix. About 80 to 90 percent are squamous cell carcinomas. The other 10 to 20 percent are adenocarcinomas. If the cancer has features of both types it is called mixed carcinoma.

Statistics

• In 2005, 493,000 women were diagnosed with cervical cancer worldwide; 10,370 of those women were in the United States ; 3,710 American women died from the disease.
• Almost all cervical cancer cases are related to the human papillomavirus (HPV).
• 72.7 percent of women diagnosed with cervical cancer will survive at least five years; that number jumps to 92.2 percent when it is diagnosed in its early stages.
• African American women are less likely to have their cancer diagnosed in an early stage (49 percent), than white women (57 percent).

Prevention

A woman can prevent most pre-cancers of the cervix by avoiding exposure to human papillomavirus or HPV. Delaying sexual intercourse if your are young, limiting your number of sexual partners and avoiding sex with people who have had many other sexual partners will lower your risk of exposure to HPV. Having HPV does not always cause warts or any other noticeable symptoms; therefore, it can be passed on from one person to another even if you are unaware that you are infected.

Avoiding tobacco smoking is another way to reduce risk of cervical cancer and pre-cancer changes in tissue. Smoking may raise the risk of cervical cancer in women exposed to HPV by slowing the body's efforts to rid itself of the HPV infection.  

Another way to prevent cervical cancer is to have routine tests to detect pre-cancerous tissue. These include a Pap test, since most invasive cervical cancers are found in women who have not had regular Pap tests. A Pap test can detect precancerous tissue that could develop into cervical cancer. Treatment can stop the cancer before it is fully developed.

Risks

While all women are at risk, some are at greater risk for developing cervical cancer. Factors that increase a woman's likelihood of cervical cancer include:

• Being infected with human papillomavirus (HPV): a sexually transmitted disease, HPVs are a group of more than 100 types of viruses that can cause warts on some parts of the body. Certain types of HPV virus can cause cancer of the cervix. These are called "high-risk HPVs." These HPV types are passed from one person to another during sex.
• Being infected with human immunodeficiency virus (HIV): The virus that causes AIDS weakens the immune system and makes a person less able to fight early cancers.  Although condoms do not protect against HPV, it is still important to use them because they do protect against AIDS and other sexually transmitted diseases.
• Smoking: Smoking can stimulate body chemicals that can create cancer-causing mutations in the DNA of cervical cells. Women who use tobacco products are twice as likely to develop cervical cancer as non-smoking women.
• Being uninsured: Women who are uninsured often cannot afford to have regular Pap tests to detect precancerous changes in tissue.
• Eating a diet low in fruits and vegetables: Some scientific studies suggest that plant foods may help protect against developing cancer. A low fat diet can help you maintain a healthy weight – obesity increases cervical cancer risk.
• Birth control pills: Long-term use of birth control pills increases the risk of cervical cancer. Some studies show a higher risk after five or more years of use. You should talk with your doctor about the pros and cons of birth control pills based on your medical history and lifestyle.
• Family history: Women whose mothers or sisters have had cervical cancer are more likely to get the disease themselves.

In addition, several ethnic groups are more likely to die of cervical cancer. Black, Hispanic and Native American women have higher cervical cancer death rates than White women, probably because of disproportionate screening practices. 

Symptoms

Pre-cancerous conditions in the cervix usually cause no symptoms and are not detected unless a woman has a pelvic exam and Pap test. Symptoms usually appear when the cancer is further along. You should report any of the following to your doctor right away:

• Increased or unusual discharge from the vagina (not your normal period)
• blood spots or light bleeding other than your normal period
• bleeding or pain during sex
• Post-menopausal bleeding (bleeding after a woman has stopped having her period)  
• Menstrual bleeding that lasts longer and is heavier than usual

These symptoms do not mean that you have cancer. They can also be caused by something else.

Regardless of your age, if you experience any of the above symptoms, see your health care professional immediately.

Early Detection

The Pap test or Pap smear is an important tool for the early detection of cervical cancer. It can detect pre-cancerous tissue and early cervical cancer, which can be treated successfully. Because of the widespread use of the Pap tests, incidence and mortality rates from cervical cancer have decreased in the United States – some data show that more than 82 percent of women aged 18 and other had had a Pap test with the last three years (2002, American Cancer Society).

It is recommended that women receive yearly Pap tests beginning three years after they become sexually active, but no later than 21 years of age. At age 30, women who have had three annual consecutive normal Pap results may elect to have the test less frequently, every two to three years, if their health care professional believes this to be safe. Speak with your health care professional to assess your risk and determine how frequently you should undergo cervical screening.

Women age 70 years and older who have had three or more consecutive normal Pap tests may choose to stop cervical cancer screening, as advised by their health care professional. Women who have undergone a total hysterectomy with removal of the cervix need not have Pap tests.

During a Pap test, your health care professional will insert a speculum into your vagina. A speculum is a plastic or metal instrument that allows your health care professional to visually check the cervix and to take a small sample of cervical cells. These will be transferred (smeared) to a slide and later examined under a microscope.

The vast majority of women who have Pap tests on a regular basis and are found to have abnormal cells will have abnormalities detected at a stage that can be easily treated.

Sometimes a woman's Pap smear suggests that cells are abnormal, when in fact they are merely inflamed due to other factors. For this reason, your health care professional may decide to do a follow-up Pap smear to confirm the presence of abnormal cells.

Women with abnormal Pap test results will have additional tests such as a colposcopy and/or biopsy to determine whether or not a precancerous change or cancer is present. An HPV test for human papilloma virus may also be performed after abnormal Pap tests to determine the present of a high risk strain of the virus, which causes cervical cancer.

In a colposcopy, an instrument with magnifying lenses (like binoculars) is used to view the cervix and vagina. The lens allows the health care professional to view the surface of the cervix closely. If abnormal areas are found, a biopsy (removal of a small amount of tissue sample) may be performed. A loop electrosurgical excision procedure, or LEEP, which removes tissue with a hot wire, is sometimes used to extract additional tissue for further study under a microscope.

Additional tests that may be performed by your health care professional include cystoscopy to determine if the cancer has spread to the bladder and proctoscopy to see if it spread to the rectum. A chest x-ray or a computerized tomography (CT) scan may also be preformed to assess the cancer's spread.

Treatment

Cervical cancer is treated through surgery, radiation therapy and chemotherapy. The type of treatment depends on the stage of the cancer, the types of cells and your age and physical condition. Cervical cancer is staged or categorized from Stage 0 (carcinoma in situ), which has not spread beyond the cervix, all the way to Stage IVB, in which the cancer has spread to distant organs.

Cryosurgery, in which liquid oxygen is used to freeze and kill cancer cells, may be used to treat cervical cancer that has not spread beyond the cervix and is not invasive. Conization is a procedure for very early stage cancer and is used to diagnose cervical cancer, as well.  In this procedure, a cone-shaped portion of the cervix is removed either by using a laser, knife or a by LEEP, loop electrosurigcal excision procedure, which uses a heated wire to destroy tissue. 

A simple hysterectomy removes the uterus and the cervix, but leaves the vagina and lymph nodes in the pelvic in tact, as well as the fallopian tubes and ovaries. More radical hysterectomy is a procedure for later stage disease that removes the entire uterus, as well as tissues next to the uterus, the upper part of the vagina next to the cervix and the pelvic lymph nodes.  Sometimes early stage disease is treated with hysterectomy for patients who are past their reproductive years.

Radiation therapy may be used instead of surgery for a few patients with very early tumors, especially in young women who wish to have children. Other patients will receive radiation therapy following surgery. External beam radiation uses x-rays externally to kill cancer cells. Brachytherapy uses a capsule of radioactive material that is placed internally near the tumor and left for several days to kill cancer cells. Some patients will have a combination of surgery, radiation and chemotherapy. Chemotherapy uses anticancer drugs given by mouth or through a vein to kill cancer cells that may have spread to other parts of the body. Sometimes a combination of drugs is given.

 

 

Cervical Cancer

Cervical cancer used to be one of the most common causes of cancer death for women in America , but more and more women are screened for cervical cancer using the Pap test , also known as a Pap smear . In 2005, an estimated 10,370 cases of cervical cancer were expected to be diagnosed.

PREVENTION

˙ Get regular screening tests.

˙ Limit number of sexual partners, and abstain from sex with people who have had

multiple partners.

RISK

All women

˙ African-American women and women age 50 and older are at higher risk

˙ Women who have sex at an early age, multiple partners or multiple pregnancies

˙ Women who have a history of sexually transmitted diseases, such as herpes,

genital warts, or Human Papilloma Virus (HPV)

˙ Women who smoke

˙ Uninsured women who do not have regular medical screening exams

SYMPTOMS

In the early stages, there usually are no symptoms. Later, these symptoms may begin to

appear:

˙ Abnormal vaginal bleeding

˙ Menstrual bleeding that is heavier and lasts longer than usual

˙ Bleeding after menopause

˙ Increased vaginal discharge

EARLY DETECTION

˙ Have annual Pap tests beginning no later than three years after starting to have

vaginal intercourse, but no later than age 21.

˙ Women who have had a total hysterectomy (surgical removal of the uterus and

cervix to treat cervical cancer or pre-cancer) should continue annual Pap tests.

TREATMENT

If caught early, most cervical cancer can be treated successfully.

˙ Surgery

˙ Cryosurgery – uses extreme cold to treat pre-cancerous conditions

˙ Radiation

˙ Chemotherapy