Understanding Microinvasion in Borderline Ovarian Tumors: What You Need to Know

Microinvasion in borderline ovarian tumors (borderline ovarian cancer) is a finding that can raise questions and concerns. When you’re already navigating a borderline ovarian tumor (BOT) diagnosis, understanding what microinvasion means for your health and treatment options becomes essential.

What Exactly is Microinvasion in Borderline Ovarian Tumors?

Microinvasion occurs when cells from a borderline tumor invade surrounding stromal tissue. Stroma is the connective tissue that gives organs structure. 

The definition of microinvasion has specific size criteria. Most studies define it as an invasion measuring 3mm in the most significant dimension, or with a surface area not exceeding 10mm². Some researchers include foci of up to 5mm. The latest World Health Organization (WHO) classification recommends using a maximum microinvasive size of 5mm, about the width of a pencil eraser.

While microinvasion most often involves the ovarian stroma (the connective tissue of the ovary), it can occasionally occur in other locations. For example, mucinous BOTs may have intestinal microinvasion, and some studies have documented cases with lymph node microinvasions.

This phenomenon occurs in about 10 to 20% of borderline ovarian tumors. The pathology can be complex, especially in cases where a BOT has microinvasion with implants in other organs like the bladder or peritoneum, as this blurs the line between BOT and low-grade serous carcinoma. You may see the term “stroma” on your pathology reports, which refers to this connective tissue invasion pattern.

How Does Microinvasion Affect My Prognosis?

The prognostic significance of microinvasion in borderline ovarian tumors depends on several factors. Stromal microinvasion alone, when not associated with extraovarian invasive implants, generally doesn’t increase the risk of recurrence or progression to invasive disease, as confirmed by large meta-analyses.

However, certain negative prognostic factors may increase recurrence risk, including advanced stage disease, invasive implants, residual tumor, micropapillary patterns, type II microinvasion (sometimes called microinvasive carcinoma), conservative surgery, and incomplete staging. When two or more of these factors are present, your healthcare team will likely recommend more intensive follow-up.

For patients with multiple risk factors, follow-up typically involves checkups every 3 months for the first 2 years, twice a year for the next 3 to 5 years, and then annually thereafter. This systematic and proactive monitoring schedule allows for early detection and intervention if recurrence occurs, while also maintaining excellent overall survival rates.

What About Treatment Options? Microinvasion in Borderline Ovarian Tumors

The presence of microinvasion doesn’t automatically require more aggressive treatment. Current research supports several encouraging approaches:

Surgery remains the primary treatment option, with various techniques available based on your specific situation. For younger women hoping to preserve fertility, surgery that spares reproductive organs often remains possible. Research shows no proven benefit from adjuvant therapy (such as chemotherapy) for microinvasive BOTs, even in advanced-stage disease or with invasive implants. However, if a primary ovarian cancer is present alongside a BOT with microinvasion, additional treatments may be necessary.

Your treatment plan will be tailored to your specific case, considering factors like your age, overall health, and personal goals. This personalized approach helps ensure you receive the most appropriate care for your situation.

Fertility and Microinvasive BOTs: Yes, It’s Possible!

Many women have successfully carried pregnancies after appropriate treatment. One study reports that approximately 50% of BOT patients achieve natural pregnancies after fertility-sparing surgery. 

However, it’s important to note that about 35% of BOT patients have a history of infertility prior to surgery, and postoperative infertility can occur due to surgical adhesions or reduced ovarian tissue.

Fertility-sparing approaches do carry an increased recurrence risk. Research shows recurrence rates of approximately 5% following radical surgery, compared to 10-20% following fertility-sparing surgery. 

The key lies in working with your healthcare team to develop a treatment strategy that addresses your health needs and fertility goals while understanding the potential tradeoffs. This might include fertility preservation options before treatment or fertility-sparing surgical approaches when appropriate.

Your doctor can help you understand the specific possibilities in your case and create a plan that aligns with your reproductive goals while ensuring proper treatment of the tumor.

Read more: Ovarian Cancer and Pregnancy: Exploring Your Fertility Options.

Follow-Up Care: What to Expect

Regular monitoring becomes an essential part of your care plan after treatment for a microinvasive BOT. Your gynecologic oncologist and healthcare team will schedule more frequent check-ups during the initial years post-treatment, typically including ultrasound examinations and blood tests to monitor tumor markers.

Consistent communication with your medical team enables the early detection of any changes. Your doctor will create a personalized follow-up schedule based on your specific case, considering factors like your age, the type of surgery performed, and your overall health status.

Research shows this systematic approach to follow-up care provides the best opportunity for early intervention if needed, though many women never experience recurrence.

Moving Forward with Confidence

Research continues to advance our understanding of microinvasion in borderline ovarian tumors, leading to refined treatment approaches and improved patient care. 

At Not These Ovaries, we actively support research initiatives to enhance treatment options and outcomes for women with BOTs. While microinvasion requires attention and careful follow-up, many women go on to live healthy, active lives after treatment. Together, we’re working toward better understanding and treatment of ovarian tumors, including those with microinvasion.